Journal of Antimicrobial Chemotherapy (1992) 29, 187-194
Awareness of need and actual use of prophylaxis: lack of patient compliance in the prevention of bacterial endocarditis Jan T. M. van der Meer*, Wflma ran Wijk*, Jan Thompson', Hans A. Valkenburg* and Marc F. Michel-
Antibiotics are given before some medical and dental procedures to patients with congenital or acquired heart disease to prevent endocarditis. The majority of practitioners and patients are aware of the need for this prophylaxis, although in practice prophylaxis is administered infrequently. It is not known how often patients at risk for endocarditis undergo procedures which warrant the prophylactic administration of antibiotics, nor how often prophylaxis is actually administered to these patients. Two groups of adult patients and a group of children with a cardiac lesion predisposing to endocarditis were surveyed by either telephone interview or mailed questionnaire about awareness of the need for prophylaxis, procedures undergone within six months of the survey and the actual use of prophylaxis before these procedures. Of 455 patients surveyed, 371 (81-5%) responded, 258 (69-5%) of whom remembered receiving advice on prophylaxis. Recollection of advice ranged from 77% of those younger than sixty years to 48% of those aged sixty or older. The patients underwent 68 procedures for which prophylaxis was definitely indicated and 71 procedures with a possible indication for prophylaxis; 127 (91%) of these procedures were dental. Antibiotics were allegedly administered before the procedure to 31 patients (22%). There is a marked discrepancy between recollection of the advice and actual use of prophylaxis. In view of this it is likely that patients often undergo procedures without antibiotic protection; however, only a few of these patients develop endocarditis.
Introduction
Patients with congenital or acquired endotheliaJ cardiac lesions have an increased risk of developing bacterial endocarditis. Antibiotic prophylaxis is recommended to reduce the risk of acquiring endocarditis due to bacteraetnia arising from a diagnostic or therapeutic procedure. In several European countries and in the United States committees of specialists in cardiology and infectious diseases have formulated guidelines for this prophylaxis (Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy, 1990; Dajani et al., 1990). In the Netherlands this was done by a •Correspondence to: Jan T. M. van der Meer, Department of Infectious Diseases, Building 1, C5P University Hospital, P.O. Box 9600, 2300 RC Leiden, The Netherlands. 0305-7453/92/020187+08 $0X00/0
187 © 1992 The British Society for Antimicrobial Chemotherapy
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
'Department of Infectious Diseases, Leiden University Hospital; bDepartment of Epidemiology and Biostatistics; 'Department of Clinical Microbiology, Erasmus University Rotterdam, The Netherlands
188
J. T. M. ran der Meer et al.
working party of the Netherlands Heart Foundation (NHF) (Michel, 1986). The Dutch recommendations in general correspond with those of other western countries (Finch, 1990). These guidelines have been widely publicized among medical and dental practitioners as well as patients. It is not known how closely these recommendations are followed. In the present study outpatients at risk for bacterial endocarditis were asked whether they recalled ever having received advice about prophylaxis, whether they had undergone any procedure in the preceding six months and, if so, whether they had taken an antibiotic. Methods
Table L Patients surveyed by mail or telephone interview Telephone survey children adults Sample size Response rate Median age (range)
100 79% 6 (1-18)
Male-female ratio
1-6
Mail survey adults
155 79%
200 85%
49-5 (17-83)
48-5 (17-88)
1-8
11
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
Tables of random numbers were used to draw three stratified samples—two groups of adults and one group of children—of the population of outpatients of the Departments of Cardiology and Paediatrics of the Leiden University Hospital (Table I). Eligibility was determined by the presence of acquired or congenital heart disease predisposing to endocarditis. Patients with a prosthetic heart valve were excluded. The population was divided into strata defined by the endocardial lesion. The sample sizes in the strata were chosen proportional to the distribution of the endocardial lesions within the population. One group of adults (« = 200) received a mailed questionnaire and a covering letter explaining the survey. Each questionnaire was accompanied by a stamped addressed return envelope. A fortnight after the first mailing a second letter was sent to non-respondents. This follow-up mailing contained another copy of the questionnaire and a reply envelope but a different accompanying letter. Of the 200 questionnaires mailed, 178 were returned (88-7%). Of these 178 questionnaires, four were sent back because the addressee had moved house. Another four were excluded because the replies were incomplete. The remaining 170 questionnaires (85%) provided the data for our study. The other group of adults (n = 155) and the children (n = 100) or their guardians were asked the same structured questions by telephone. First a letter was sent to these patients to introduce and explain the study. The letter was accompanied by a list of procedures intended to refresh the patient's memory. Within five days of this mailing the patient was called. All calls were made on weekdays between 9.00 a.m. and 10.00 p.m. to avoid selection according to employment or disease status. At least four attempts were made to contact the subject. Telephone interviews were completed with 122 of 155 adult patients (79%) and 79 of 100 children (79%). The questionnaire covered all procedures for which antibiotic prophylaxis is indicated, according to the recommendations of the NHF. When sufficient information
Patient compliance with giridrifnm for endocarditis prophylaxis
189
Results Overall, 69-5% of the patients remembered receiving advice about prophylaxis. There was no significant difference in awareness between men and women (RR 098, 95% CI 086-1 12), nor between patients according to type of endocardial lesion (RR 091, 95% CI, 079-116). Remembrance was age-related and ranged from 77% of those younger than sixty years to 48% of those aged sixty or older (RR 1-6, 95% CI 1-3-2-0) (Figure). Adult patients (n = 292) and children (n = 79) differed significantly in the
80
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Figure. Patient awareness of need for endocarditis prophylaxis according to age.
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about the procedure was available to establish the indication for prophylaxis with certainty, it was entered as 'definite', if not, the prophylaxis indication was entered as 'possible'. The 'definite' group consisted of procedures with a high risk of bacteraemia, such as dental root work or digestive tract surgery. The 'possible' group consisted of procedures with a low risk of bacteraemia, mainly dental scaling. According to the NHF guidelines prophylaxis is indicated for scaling when and if it includes the subgingival removal of tartar or when it is combined with polishing of the teeth. However, most patients did not know whether or not scaling had included the subgingival removal of tartar or polishing. For procedures not specifically mentioned in the guidelines of the NHF the indication for prophylaxis was entered as 'no'. Information was obtained on procedures undergone within six months of the survey. When a patient had undergone more than one procedure, all were entered. In addition the actual use of prophylaxis, as reported by the patient, was registered. Ratio, median and means were compared by means of the chi-square test and the non-parametric Mann-Whitney U test Relative risks (RR) and 95% confidence intervals (95% CI) were calculated using a computer program for statistical analysis (Gardner & Altman, 1988).
J. T. M. ran der Meer et at.
190
number of high-risk procedures undergone within six months of the survey, 127 and 12, respectively (RR 2-86, 95% CI 1-67^-90). When stratified according to certainty of indication for prophylaxis adults and children did not differ significantly in type of procedure (medical or dental) or use of prophylaxis. Adults
Table II. Indications for and compliance with prophylaxis in 292 adult patients Indication for prophylaxis possible'
definite* Dental root canal therapy acute gingivitis extraction avulsion cementation of a jacket-crown polishing Other haemorrtaoidectomy bronchial lavage
Total
5/9* 2/3 7/8 1/12
removal of calculus removal of calculus plus dental filling
6/53*
no' routine check dental filling
0/35' 4/25
endoscopy bronchoscop/
1/10 0/4
orchidectomy ear operation cardiac catheterization cardiac surgery orthopaedic surgery berniotomy mastectomy mole excision
0/2 1/3 1/9 5/8 4/4 1/1 1/1 1/1
2/11
0/3 2/20 1/2
o/i
18/58
0/2 cystoscopy vocal cord operation 2/2 sebaceous cyst excision 1/1
11/69
19/103
Indication for prophylaxis according to the guidelines of the Netherlands Heart Foundation (NHF). 'Expressed as number of patients given prophylaxis per number of patients undergoing procedure. I f the information available was insufficient to establish a prophylaxis indication with certainty, the indication was entered as 'possible'. 'No indication for prophylaxis according to the guidelines of the NHF. 'Fibreoptk bronchoscopy, in one case with biopsy.
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
Adult patients surveyed by mail did not differ significantly from adults surveyed by telephone in age (P = 0-70), sex (P = 0-06) or awareness of need for prophylaxis: 66-5% and 70-5%, respectively (P = 0-27). Together, these patients (n = 292) had undergone 230 medical or dental procedures during the preceding six months, ranging from a routine dental check to major surgery (Table IT). The majority of the procedures with an indication for prophylaxis was dental: 119 of 127 or 94%. Prophylaxis was definitely indicated for 58 of the 127 procedures; root canal therapy, extractions and other procedures with a high risk for bacteraemia. For 69 procedures the indication for prophylaxis could not be determined with certainty; 61 of these procedures involved removal of dental calculus. Antibiotics were administered before the procedure in 29 of the 127 cases (22-8%); 18 of 58 cases (31%) undergoing a procedure with a 'definite'
Patient compliance with gnttetines for endocarditis prophylaxis
191
Table ED. Indications for and compliance with prophylaxis in 79 children Indication for prophylaxis possible'
definite"
no'
1/1* 0/1 0/2 0/3
removal of calculus
0/1*
routine check dental filling
0/51* 0/3
Other sinus drainage tonsillectomy
0/1 1/2
tithotripsy
0/1
tympanostomy tubes cardiac catheterization cardiac surgery herniotomy
1/2 0/1 4/4
Total
2/10
0/2
1/1 6/62
For footnotes see Table n.
indication and 11 of 69 patients (16%) undergoing a procedure with a 'possible' indication. When stratified according to certainty of prophylaxis indication adults surveyed by mail did not differ significantly from those surveyed by telephone in actual use of prophylaxis (RR 1-27, 95% CI 0-95-1-70). None of these patients developed endocarditis in the six months following the survey. Children
Seventy-five per cent of the children and/or their guardians remembered receiving advice on prophylaxis. The children underwent a total of 74 procedures (Table III). Prophylaxis was definitely indicated for ten of the 74 procedures. For two procedures the indication for prophylaxis could not be determined with certainty. Of the ten procedures with a definite indication seven were dental. Prophylaxis was instituted in only two instances. Neither of the two children undergoing a procedure with a 'possible' indication received prophylaxis. One of the children developed endocarditis following dental filling, a procedure without an indication for prophylaxis. However, since the interval between the procedure and the onset of symptoms was ten weeks and in view of the type of procedure, it is unlikely that the disease occurred as a consequence of the procedure. Discussion
The results of this study show a marked discrepancy between awareness of advice and the actual use of prophylaxis. In the literature, the proportion of patients who remember advice on prophylaxis varies from 7% to 78% (Harvey & Capone, 1961; Kramer et al., 1982; Sholler & Celermajer, 1984; Pitcher et al., 1986; Vickers, 1987) which is consistent with the 69-5% found in this study. Studies on compliance with current guidelines by medical and dental practitioners, assessed by means of telephone interviews or self-administered questionnaires, suggest that medical professionals are aware of the need for prophylaxis but have a relatively low level of knowledge of
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Dental root canal therapy acute gingivitis extraction avulsion
192
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correct indications and regimens (Durack, 1975; Meyer, 1979; Brooks, 1980; Hashway & Stone, 1982; Holbrook, Willey & Shaw, 1983; Kaplowitz & Reifler, 1983; Gould, 1984; Gaidry et al., 1985; Levers & Scully, 1986; Sadowsky & Kunzel, 1986; Holbrook, Higgins & Shaw, 1987; Scully et al., 1987; Delaye, Etienne & Delahaye, 1988; Raby, 1988; Sadowsky & Kunzel, 1988; Kunzel & Sadowsky, 1989; Nelson & Van Blaricum, 1989; Gould, 1990; Gutschik & Lippert, 1990; Murenha & Stein, 1990). Other studies indicate that in practice clinicians frequently do not apply prophylaxis. In the study of Jaspers, Little & Hartwick (1984) proper documentation of actually administered antibiotics was found for 19 of 37 dental patients (51%) requiring prophylaxis. For 825 dental procedures with an indication for prophylaxis, Murrah et al. (1987) found in only 347 (42%) some documentation of actually administered prophylaxis. Brooks, Notario & McCabe (1988) found that compliance with the American Heart Association guidelines was only 30% for patients with a prosthetic heart valve undergoing a highrisk procedure. Of these patients 39% received no prophylaxis at all. In the series of Gutschik & Lippert (1989) 30-4% of patients received prophylaxis for dental extraction and 13-8% for scaling. In the present study 22-3% of all patients allegedly received prophylaxis; 29-4% (20 of 68) for high-risk procedures such as dental root work or extraction and 15-5% (11 of 71) for low-risk procedures such as dental scaling. Although comparison of these studies is difficult because of differences in populations studied and variations in methods and end points, the data suggest that low compliance is common even though both patients and practitioners are aware of the need for prophylaxis. The low compliance might be due to the absence of an evident relation between medical or dental procedures and the development of a subsequent endocarditis. This might apply in particular for patients, although it is not clear how the patient's awareness contributes to the use of prophylaxis by medical practitioners. In view of the low compliance, we may assume that many people at risk for endocarditis undergo procedures without antibiotic protection and yet only a few of them develop endocarditis. The incidence of bacterial endocarditis in the Netherlands is 19 cases per million per year, only 7% occurring within 30 days of a procedure in a patient previously known to have heart disease (Van der Meer et al., unpublished). Therefore, the risk of contracting endocarditis from a bacteraemia following a procedure must be small. Irrespective of prophylaxis, the odds are that a patient will not develop endocarditis as a consequence of the procedure. This undoubtedly contributes to the non-adherent behaviour of patients and possibly also doctors and dentists. Moreover, it raises the question whether the low compliance need be combatted at all. After all, low compliance constitutes a problem only if prophylaxis does more good than harm to those who comply. Whether this is the case depends on the risk of post-procedure endocarditis and the protective efficacy of prophylaxis versus the chance of severe adverse reactions to the antibiotics. Unfortunately, we do not know the risk of postprocedure endocarditis for individual patients since a number of variables such as sex, age, underlying cardiac lesion and the type of procedure contribute to the probability. However, analysis of the benefits and risks of prophylaxis for patients with mitral valve prolapse—who have a relatively low risk for endocarditis—indicated that no prophylaxis and prophylaxis with penicillin would result in a similar number of deaths; parenteral penicillin might even cause a net loss of life (Bor & Himmelstein, 1984; Clemens & Ransohoff, 1984; Hickey, MacMahon & Wilcken, 1985). Estimates of risks for other cardiac lesions are hampered by the lack of prevalence figures for these lesions which makes it impossible to obtain a reliable denominator.
Patient compliance wtth guidelines for endocarditis prophylaxis
193
In conclusion, low compliance with endocarditis guidelines is common. None the less, endocarditis as the consequence of a procedure is an uncommon event. Under certain circumstances the risks of prophylaxis outweigh the benefits, so it is debatable whether efforts to improve compliance with prophylaxis guidelines should be made. Acknowledgements
References Bor, D. H. & Himmelstein, D. U. (1984). Endocarditis prophylaxis for patients with mitral valve prolapse. A quantitative analysis. American Journal of Medicine 76, 711-7. Brooks, R. G., Notario, G. & McCabe, R. E. (1988). Hospital survey of antimicrobial prophylaxis to prevent endocarditis in patients with prosthetic heart valves. American Journal of Medicine 84, 617-21. Brooks, S. L. (1980). Survey of compliance with American Heart Association guidelines for prevention of bacterial endocarditis. Journal of the American Dental Association 101, 41-3. Clemens, J. D. & Ransohoff, D. F. (1984). A quantitative assessment of pre-dental antibiotic prophylaxis for patients with mitral-valve prolapse. Journal of Chronic Disease 37, 531-44. Dajani, A. S., Bisno, A. L., Chung, K. J., Durack, D. T., Freed, M., Gerber, M. A. et at. (1990). Prevention of bacterial endocarditis. Recommendations by the American Heart Association. Journal of the American Medical Association 264, 2919-22. Dclaye, J., Etienne, J. & Delahaye, F. (1988). La prophylaxie anti-oslerienne en 1987. De la theorie a l'application pratique. Presse Medicate 17, 185-6. Durack, D. T. (1975). Current practice in prevention of bacterial endocarditis. British Heart Journal 37, 478-81. Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy. (1990). Antibiotic prophylaxis of infective endocarditis. Recommendations from the Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy. Lancet 335, 88-9. Finch, R. (1990). Chemoprophylaxis of infective endocarditis. Scandinavian Journal of Infectious Diseases, Suppl. 70, 102-10. Gaidry, D., Kudlick, E. M., Hutton, J. G. & Russell, D. M. (1985). A survey to evaluate the management of orthodontic patients with a history of rheumatic fever or congenital heart disease. American Journal of Orthodontics 87, 338-44. Gardner, M. J. & Altman, D. G., Eds (1989). Statistics with Confidence. British Medical Journal, London. Gould, I. M. (1984). Chemoprophylaxis for bacterial endocarditis—a survey of current practice in London. Journal of Antimicrobial Chemotherapy 14, 379-94. Gould, I. M. (1990). Current prophylaxis for prevention of infective endocarditis. British Dental Journal 168, 409-10. Gutschik, E. & Lippert, S. (1989). Dental procedures and endocarditis prophylaxis in patients with prosthetic heart valves: results of a questionnaire to 220 patients. Scandinavian Journal of Infectious Diseases 21, 665-8. Gutschik, E. & Lippert, S. (1990). Dental procedures and endocarditis prophylaxis: experiences from 108 dental practices. Scandinavian Journal of Dental Research 98, 144-8. Harvey, W. P. & Capone, M. A. (1961). Bacterial endocarditis related to cleaning and filling of teeth with particular reference to the inadequacy of present day knowledge and practice of antibiotic prophylaxis for all dental procedures. American Journal of Cardiology 7, 793-8. Hashway, T. & Stone, L. J. (1982). Antibiotic prophylaxis of subacute bacterial endocarditis for adult patients by dentists in Dade County, Florida. Circulation 66, 1110-3.
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
We like to thank Professors A. V. G. Bruschke and J. Rohmer for allowing us to study patients under the care of their departments and Professor R. van Furth for his critical review of the manuscript We are indebted to Mrs J. van Beckhoven and J. Zeeman for their assistance in collecting the data and to Mrs M. Kerst-Noest for her secretarial assistance.
194
J. T. M. ran der Meet et at.
(Received 24 July 1991; accepted 22 October 1991)
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Hickcy, A. J., MacMahon, S. W. & Wilcken, D. E. L. (1985). Mitral valve prolapse and bacterial endocarditis: when is antibiotic prophylaxis necessary? American Heart Journal 109, 431-5. Holbrook, W. P., Higgins, B. & Shaw, T. R. D. (1987). Recent changes in antibiotic prophylactic measures taken by dentists against infective endocarditis. Journal of Antimicrobial Chemotherapy 20, 439-46. Holbrook, W. P., Willey, R. F. & Shaw, T. R. D. (1983). Prophylaxis of infective endocarditis. British Dental Journal 154, 36-9. Jaspers, M. T., Little, J. W. & Hartwick, W. L. (1984). Effectiveness of a dental school program in the prevention of infective endocarditis and other related infections. Journal of Dental Education 48, 159-63. Kaplowitz, G. J. & Reifler, J. R. F. (1983). Compliance with AHA guidelines for preventing bacterial endocarditis: report of a study. General Dentistry 31, 56-8. Kramer, H. H., Liersch, R., Sievers, G. & Bourgeois, M. (1982). Prevention der bakteriellcn Endokarditis in der Praxis. Ergebnisse einer Elterbefragung. Monatsschrift KinderheUkunde 130, 504-7. Kunzcl, C. & Sadowsky, D. (1989). Knowledge acquisition processes: dissemination of expert recommendations to general practice dentists. Journal of Health and Social Behavior 30, 330-43. Levers, B. G. H. & Scully, C. (1986). Antimicrobial prophylaxis of endocarditis: compliance of dental practitioners with British recommendations. Journal of Dental Research 65, Special Issue, 789. Meyer, G. W. (1979). Prophylaxis of infective endocarditis during gastrointestinal procedures: report of a survey. Gastrointestinal Endoscopy 25, 1-2. Michel, M. F. (1986). Review of the guidelines of the Dutch Heart Foundation for the prevention of endocarditis. Nederlands Tijdschrift voor Geneeskunde 130, 2211-12. Murenha, E. & Stein, C. M. (1990). Chemoprophylaxis of bacterial endocarditis—a survey of current practice in Zimbabwe. Journal of Antimicrobial Chemotherapy 25, 291-6. Murrah, V. A., Merry, J. W., Little, J. W. & Jaspers, M. T. (1987). Compliance with guidelines for management of dental school patients susceptible to infective endocarditis. Journal of Dental Education 51, 229-32. Nelson, C. L. & Van Blaricum, C. S. (1989). Physician and dentist compliance with American Heart Association guidelines for prevention of bacterial endocarditis. Journal of the American Dental Association 118, 169-73. Pitcher, D. W., Papouchado, M., Channer, K. S. & James, M. A. (1986). Endocarditis prophylaxis: do patients remember advice and know what to do? British Medical Journal 293, 1539^40. Raby, N. (1988). Radiological awareness of current recommendations on prophylaxis of infective endocarditis. British Journal of Radiology 61, 366-7. Sadowsky, D. & Kunzel, C. (1986). A study of the implementation of endocarditis prevention in patients at risk. New York State Dental Journal 52, 34-7. Sadowsky, D. & Kunzel, C. (1988). Recommendations for prevention of bacterial endocarditis: compliance by dental practitioners. Circulation Tl, 1316-8. Sadowsky, D. & Kunzel, C. (1989). 'Usual and customary' practice versus the recommendations of experts: clinician noncompliance in the prevention of bacterial endocarditis. Journal of American Dental Association 118, 175-80. Scully, C. M. Levers, B. G. H., Griffiths, M. J. & Shirlaw, P. J. (1987). Antimicrobial prophylaxis of infective endocarditis: effect of BSAC recommendations on compliance in general practice. Journal of Antimicrobial Chemotherapy 19, 521-6. Sholler, G. F. & Celermajer, J. M. (1984). Prophylaxis of bacterial endocarditis. Awareness of need. Medical Journal of Australia 140, 650-2. Vickers, D. (1987). Endocarditis prophylaxis: do parents remember advice? British Medical Journal 294, 247.
Awareness of need and actual use of prophylaxis: lack of patient compliance in the prevention of bacterial endocarditis Jan T. M. van der Meer*, Wflma ran Wijk*, Jan Thompson', Hans A. Valkenburg* and Marc F. Michel-
Antibiotics are given before some medical and dental procedures to patients with congenital or acquired heart disease to prevent endocarditis. The majority of practitioners and patients are aware of the need for this prophylaxis, although in practice prophylaxis is administered infrequently. It is not known how often patients at risk for endocarditis undergo procedures which warrant the prophylactic administration of antibiotics, nor how often prophylaxis is actually administered to these patients. Two groups of adult patients and a group of children with a cardiac lesion predisposing to endocarditis were surveyed by either telephone interview or mailed questionnaire about awareness of the need for prophylaxis, procedures undergone within six months of the survey and the actual use of prophylaxis before these procedures. Of 455 patients surveyed, 371 (81-5%) responded, 258 (69-5%) of whom remembered receiving advice on prophylaxis. Recollection of advice ranged from 77% of those younger than sixty years to 48% of those aged sixty or older. The patients underwent 68 procedures for which prophylaxis was definitely indicated and 71 procedures with a possible indication for prophylaxis; 127 (91%) of these procedures were dental. Antibiotics were allegedly administered before the procedure to 31 patients (22%). There is a marked discrepancy between recollection of the advice and actual use of prophylaxis. In view of this it is likely that patients often undergo procedures without antibiotic protection; however, only a few of these patients develop endocarditis.
Introduction
Patients with congenital or acquired endotheliaJ cardiac lesions have an increased risk of developing bacterial endocarditis. Antibiotic prophylaxis is recommended to reduce the risk of acquiring endocarditis due to bacteraetnia arising from a diagnostic or therapeutic procedure. In several European countries and in the United States committees of specialists in cardiology and infectious diseases have formulated guidelines for this prophylaxis (Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy, 1990; Dajani et al., 1990). In the Netherlands this was done by a •Correspondence to: Jan T. M. van der Meer, Department of Infectious Diseases, Building 1, C5P University Hospital, P.O. Box 9600, 2300 RC Leiden, The Netherlands. 0305-7453/92/020187+08 $0X00/0
187 © 1992 The British Society for Antimicrobial Chemotherapy
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
'Department of Infectious Diseases, Leiden University Hospital; bDepartment of Epidemiology and Biostatistics; 'Department of Clinical Microbiology, Erasmus University Rotterdam, The Netherlands
188
J. T. M. ran der Meer et al.
working party of the Netherlands Heart Foundation (NHF) (Michel, 1986). The Dutch recommendations in general correspond with those of other western countries (Finch, 1990). These guidelines have been widely publicized among medical and dental practitioners as well as patients. It is not known how closely these recommendations are followed. In the present study outpatients at risk for bacterial endocarditis were asked whether they recalled ever having received advice about prophylaxis, whether they had undergone any procedure in the preceding six months and, if so, whether they had taken an antibiotic. Methods
Table L Patients surveyed by mail or telephone interview Telephone survey children adults Sample size Response rate Median age (range)
100 79% 6 (1-18)
Male-female ratio
1-6
Mail survey adults
155 79%
200 85%
49-5 (17-83)
48-5 (17-88)
1-8
11
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
Tables of random numbers were used to draw three stratified samples—two groups of adults and one group of children—of the population of outpatients of the Departments of Cardiology and Paediatrics of the Leiden University Hospital (Table I). Eligibility was determined by the presence of acquired or congenital heart disease predisposing to endocarditis. Patients with a prosthetic heart valve were excluded. The population was divided into strata defined by the endocardial lesion. The sample sizes in the strata were chosen proportional to the distribution of the endocardial lesions within the population. One group of adults (« = 200) received a mailed questionnaire and a covering letter explaining the survey. Each questionnaire was accompanied by a stamped addressed return envelope. A fortnight after the first mailing a second letter was sent to non-respondents. This follow-up mailing contained another copy of the questionnaire and a reply envelope but a different accompanying letter. Of the 200 questionnaires mailed, 178 were returned (88-7%). Of these 178 questionnaires, four were sent back because the addressee had moved house. Another four were excluded because the replies were incomplete. The remaining 170 questionnaires (85%) provided the data for our study. The other group of adults (n = 155) and the children (n = 100) or their guardians were asked the same structured questions by telephone. First a letter was sent to these patients to introduce and explain the study. The letter was accompanied by a list of procedures intended to refresh the patient's memory. Within five days of this mailing the patient was called. All calls were made on weekdays between 9.00 a.m. and 10.00 p.m. to avoid selection according to employment or disease status. At least four attempts were made to contact the subject. Telephone interviews were completed with 122 of 155 adult patients (79%) and 79 of 100 children (79%). The questionnaire covered all procedures for which antibiotic prophylaxis is indicated, according to the recommendations of the NHF. When sufficient information
Patient compliance with giridrifnm for endocarditis prophylaxis
189
Results Overall, 69-5% of the patients remembered receiving advice about prophylaxis. There was no significant difference in awareness between men and women (RR 098, 95% CI 086-1 12), nor between patients according to type of endocardial lesion (RR 091, 95% CI, 079-116). Remembrance was age-related and ranged from 77% of those younger than sixty years to 48% of those aged sixty or older (RR 1-6, 95% CI 1-3-2-0) (Figure). Adult patients (n = 292) and children (n = 79) differed significantly in the
80
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Figure. Patient awareness of need for endocarditis prophylaxis according to age.
Downloaded from http://jac.oxfordjournals.org/ at New York University on April 16, 2015
about the procedure was available to establish the indication for prophylaxis with certainty, it was entered as 'definite', if not, the prophylaxis indication was entered as 'possible'. The 'definite' group consisted of procedures with a high risk of bacteraemia, such as dental root work or digestive tract surgery. The 'possible' group consisted of procedures with a low risk of bacteraemia, mainly dental scaling. According to the NHF guidelines prophylaxis is indicated for scaling when and if it includes the subgingival removal of tartar or when it is combined with polishing of the teeth. However, most patients did not know whether or not scaling had included the subgingival removal of tartar or polishing. For procedures not specifically mentioned in the guidelines of the NHF the indication for prophylaxis was entered as 'no'. Information was obtained on procedures undergone within six months of the survey. When a patient had undergone more than one procedure, all were entered. In addition the actual use of prophylaxis, as reported by the patient, was registered. Ratio, median and means were compared by means of the chi-square test and the non-parametric Mann-Whitney U test Relative risks (RR) and 95% confidence intervals (95% CI) were calculated using a computer program for statistical analysis (Gardner & Altman, 1988).
J. T. M. ran der Meer et at.
190
number of high-risk procedures undergone within six months of the survey, 127 and 12, respectively (RR 2-86, 95% CI 1-67^-90). When stratified according to certainty of indication for prophylaxis adults and children did not differ significantly in type of procedure (medical or dental) or use of prophylaxis. Adults
Table II. Indications for and compliance with prophylaxis in 292 adult patients Indication for prophylaxis possible'
definite* Dental root canal therapy acute gingivitis extraction avulsion cementation of a jacket-crown polishing Other haemorrtaoidectomy bronchial lavage
Total
5/9* 2/3 7/8 1/12
removal of calculus removal of calculus plus dental filling
6/53*
no' routine check dental filling
0/35' 4/25
endoscopy bronchoscop/
1/10 0/4
orchidectomy ear operation cardiac catheterization cardiac surgery orthopaedic surgery berniotomy mastectomy mole excision
0/2 1/3 1/9 5/8 4/4 1/1 1/1 1/1
2/11
0/3 2/20 1/2
o/i
18/58
0/2 cystoscopy vocal cord operation 2/2 sebaceous cyst excision 1/1
11/69
19/103
Indication for prophylaxis according to the guidelines of the Netherlands Heart Foundation (NHF). 'Expressed as number of patients given prophylaxis per number of patients undergoing procedure. I f the information available was insufficient to establish a prophylaxis indication with certainty, the indication was entered as 'possible'. 'No indication for prophylaxis according to the guidelines of the NHF. 'Fibreoptk bronchoscopy, in one case with biopsy.
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Adult patients surveyed by mail did not differ significantly from adults surveyed by telephone in age (P = 0-70), sex (P = 0-06) or awareness of need for prophylaxis: 66-5% and 70-5%, respectively (P = 0-27). Together, these patients (n = 292) had undergone 230 medical or dental procedures during the preceding six months, ranging from a routine dental check to major surgery (Table IT). The majority of the procedures with an indication for prophylaxis was dental: 119 of 127 or 94%. Prophylaxis was definitely indicated for 58 of the 127 procedures; root canal therapy, extractions and other procedures with a high risk for bacteraemia. For 69 procedures the indication for prophylaxis could not be determined with certainty; 61 of these procedures involved removal of dental calculus. Antibiotics were administered before the procedure in 29 of the 127 cases (22-8%); 18 of 58 cases (31%) undergoing a procedure with a 'definite'
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Table ED. Indications for and compliance with prophylaxis in 79 children Indication for prophylaxis possible'
definite"
no'
1/1* 0/1 0/2 0/3
removal of calculus
0/1*
routine check dental filling
0/51* 0/3
Other sinus drainage tonsillectomy
0/1 1/2
tithotripsy
0/1
tympanostomy tubes cardiac catheterization cardiac surgery herniotomy
1/2 0/1 4/4
Total
2/10
0/2
1/1 6/62
For footnotes see Table n.
indication and 11 of 69 patients (16%) undergoing a procedure with a 'possible' indication. When stratified according to certainty of prophylaxis indication adults surveyed by mail did not differ significantly from those surveyed by telephone in actual use of prophylaxis (RR 1-27, 95% CI 0-95-1-70). None of these patients developed endocarditis in the six months following the survey. Children
Seventy-five per cent of the children and/or their guardians remembered receiving advice on prophylaxis. The children underwent a total of 74 procedures (Table III). Prophylaxis was definitely indicated for ten of the 74 procedures. For two procedures the indication for prophylaxis could not be determined with certainty. Of the ten procedures with a definite indication seven were dental. Prophylaxis was instituted in only two instances. Neither of the two children undergoing a procedure with a 'possible' indication received prophylaxis. One of the children developed endocarditis following dental filling, a procedure without an indication for prophylaxis. However, since the interval between the procedure and the onset of symptoms was ten weeks and in view of the type of procedure, it is unlikely that the disease occurred as a consequence of the procedure. Discussion
The results of this study show a marked discrepancy between awareness of advice and the actual use of prophylaxis. In the literature, the proportion of patients who remember advice on prophylaxis varies from 7% to 78% (Harvey & Capone, 1961; Kramer et al., 1982; Sholler & Celermajer, 1984; Pitcher et al., 1986; Vickers, 1987) which is consistent with the 69-5% found in this study. Studies on compliance with current guidelines by medical and dental practitioners, assessed by means of telephone interviews or self-administered questionnaires, suggest that medical professionals are aware of the need for prophylaxis but have a relatively low level of knowledge of
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Dental root canal therapy acute gingivitis extraction avulsion
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correct indications and regimens (Durack, 1975; Meyer, 1979; Brooks, 1980; Hashway & Stone, 1982; Holbrook, Willey & Shaw, 1983; Kaplowitz & Reifler, 1983; Gould, 1984; Gaidry et al., 1985; Levers & Scully, 1986; Sadowsky & Kunzel, 1986; Holbrook, Higgins & Shaw, 1987; Scully et al., 1987; Delaye, Etienne & Delahaye, 1988; Raby, 1988; Sadowsky & Kunzel, 1988; Kunzel & Sadowsky, 1989; Nelson & Van Blaricum, 1989; Gould, 1990; Gutschik & Lippert, 1990; Murenha & Stein, 1990). Other studies indicate that in practice clinicians frequently do not apply prophylaxis. In the study of Jaspers, Little & Hartwick (1984) proper documentation of actually administered antibiotics was found for 19 of 37 dental patients (51%) requiring prophylaxis. For 825 dental procedures with an indication for prophylaxis, Murrah et al. (1987) found in only 347 (42%) some documentation of actually administered prophylaxis. Brooks, Notario & McCabe (1988) found that compliance with the American Heart Association guidelines was only 30% for patients with a prosthetic heart valve undergoing a highrisk procedure. Of these patients 39% received no prophylaxis at all. In the series of Gutschik & Lippert (1989) 30-4% of patients received prophylaxis for dental extraction and 13-8% for scaling. In the present study 22-3% of all patients allegedly received prophylaxis; 29-4% (20 of 68) for high-risk procedures such as dental root work or extraction and 15-5% (11 of 71) for low-risk procedures such as dental scaling. Although comparison of these studies is difficult because of differences in populations studied and variations in methods and end points, the data suggest that low compliance is common even though both patients and practitioners are aware of the need for prophylaxis. The low compliance might be due to the absence of an evident relation between medical or dental procedures and the development of a subsequent endocarditis. This might apply in particular for patients, although it is not clear how the patient's awareness contributes to the use of prophylaxis by medical practitioners. In view of the low compliance, we may assume that many people at risk for endocarditis undergo procedures without antibiotic protection and yet only a few of them develop endocarditis. The incidence of bacterial endocarditis in the Netherlands is 19 cases per million per year, only 7% occurring within 30 days of a procedure in a patient previously known to have heart disease (Van der Meer et al., unpublished). Therefore, the risk of contracting endocarditis from a bacteraemia following a procedure must be small. Irrespective of prophylaxis, the odds are that a patient will not develop endocarditis as a consequence of the procedure. This undoubtedly contributes to the non-adherent behaviour of patients and possibly also doctors and dentists. Moreover, it raises the question whether the low compliance need be combatted at all. After all, low compliance constitutes a problem only if prophylaxis does more good than harm to those who comply. Whether this is the case depends on the risk of post-procedure endocarditis and the protective efficacy of prophylaxis versus the chance of severe adverse reactions to the antibiotics. Unfortunately, we do not know the risk of postprocedure endocarditis for individual patients since a number of variables such as sex, age, underlying cardiac lesion and the type of procedure contribute to the probability. However, analysis of the benefits and risks of prophylaxis for patients with mitral valve prolapse—who have a relatively low risk for endocarditis—indicated that no prophylaxis and prophylaxis with penicillin would result in a similar number of deaths; parenteral penicillin might even cause a net loss of life (Bor & Himmelstein, 1984; Clemens & Ransohoff, 1984; Hickey, MacMahon & Wilcken, 1985). Estimates of risks for other cardiac lesions are hampered by the lack of prevalence figures for these lesions which makes it impossible to obtain a reliable denominator.
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In conclusion, low compliance with endocarditis guidelines is common. None the less, endocarditis as the consequence of a procedure is an uncommon event. Under certain circumstances the risks of prophylaxis outweigh the benefits, so it is debatable whether efforts to improve compliance with prophylaxis guidelines should be made. Acknowledgements
References Bor, D. H. & Himmelstein, D. U. (1984). Endocarditis prophylaxis for patients with mitral valve prolapse. A quantitative analysis. American Journal of Medicine 76, 711-7. Brooks, R. G., Notario, G. & McCabe, R. E. (1988). Hospital survey of antimicrobial prophylaxis to prevent endocarditis in patients with prosthetic heart valves. American Journal of Medicine 84, 617-21. Brooks, S. L. (1980). Survey of compliance with American Heart Association guidelines for prevention of bacterial endocarditis. Journal of the American Dental Association 101, 41-3. Clemens, J. D. & Ransohoff, D. F. (1984). A quantitative assessment of pre-dental antibiotic prophylaxis for patients with mitral-valve prolapse. Journal of Chronic Disease 37, 531-44. Dajani, A. S., Bisno, A. L., Chung, K. J., Durack, D. T., Freed, M., Gerber, M. A. et at. (1990). Prevention of bacterial endocarditis. Recommendations by the American Heart Association. Journal of the American Medical Association 264, 2919-22. Dclaye, J., Etienne, J. & Delahaye, F. (1988). La prophylaxie anti-oslerienne en 1987. De la theorie a l'application pratique. Presse Medicate 17, 185-6. Durack, D. T. (1975). Current practice in prevention of bacterial endocarditis. British Heart Journal 37, 478-81. Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy. (1990). Antibiotic prophylaxis of infective endocarditis. Recommendations from the Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy. Lancet 335, 88-9. Finch, R. (1990). Chemoprophylaxis of infective endocarditis. Scandinavian Journal of Infectious Diseases, Suppl. 70, 102-10. Gaidry, D., Kudlick, E. M., Hutton, J. G. & Russell, D. M. (1985). A survey to evaluate the management of orthodontic patients with a history of rheumatic fever or congenital heart disease. American Journal of Orthodontics 87, 338-44. Gardner, M. J. & Altman, D. G., Eds (1989). Statistics with Confidence. British Medical Journal, London. Gould, I. M. (1984). Chemoprophylaxis for bacterial endocarditis—a survey of current practice in London. Journal of Antimicrobial Chemotherapy 14, 379-94. Gould, I. M. (1990). Current prophylaxis for prevention of infective endocarditis. British Dental Journal 168, 409-10. Gutschik, E. & Lippert, S. (1989). Dental procedures and endocarditis prophylaxis in patients with prosthetic heart valves: results of a questionnaire to 220 patients. Scandinavian Journal of Infectious Diseases 21, 665-8. Gutschik, E. & Lippert, S. (1990). Dental procedures and endocarditis prophylaxis: experiences from 108 dental practices. Scandinavian Journal of Dental Research 98, 144-8. Harvey, W. P. & Capone, M. A. (1961). Bacterial endocarditis related to cleaning and filling of teeth with particular reference to the inadequacy of present day knowledge and practice of antibiotic prophylaxis for all dental procedures. American Journal of Cardiology 7, 793-8. Hashway, T. & Stone, L. J. (1982). Antibiotic prophylaxis of subacute bacterial endocarditis for adult patients by dentists in Dade County, Florida. Circulation 66, 1110-3.
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We like to thank Professors A. V. G. Bruschke and J. Rohmer for allowing us to study patients under the care of their departments and Professor R. van Furth for his critical review of the manuscript We are indebted to Mrs J. van Beckhoven and J. Zeeman for their assistance in collecting the data and to Mrs M. Kerst-Noest for her secretarial assistance.
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(Received 24 July 1991; accepted 22 October 1991)
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Hickcy, A. J., MacMahon, S. W. & Wilcken, D. E. L. (1985). Mitral valve prolapse and bacterial endocarditis: when is antibiotic prophylaxis necessary? American Heart Journal 109, 431-5. Holbrook, W. P., Higgins, B. & Shaw, T. R. D. (1987). Recent changes in antibiotic prophylactic measures taken by dentists against infective endocarditis. Journal of Antimicrobial Chemotherapy 20, 439-46. Holbrook, W. P., Willey, R. F. & Shaw, T. R. D. (1983). Prophylaxis of infective endocarditis. British Dental Journal 154, 36-9. Jaspers, M. T., Little, J. W. & Hartwick, W. L. (1984). Effectiveness of a dental school program in the prevention of infective endocarditis and other related infections. Journal of Dental Education 48, 159-63. Kaplowitz, G. J. & Reifler, J. R. F. (1983). Compliance with AHA guidelines for preventing bacterial endocarditis: report of a study. General Dentistry 31, 56-8. Kramer, H. H., Liersch, R., Sievers, G. & Bourgeois, M. (1982). Prevention der bakteriellcn Endokarditis in der Praxis. Ergebnisse einer Elterbefragung. Monatsschrift KinderheUkunde 130, 504-7. Kunzcl, C. & Sadowsky, D. (1989). Knowledge acquisition processes: dissemination of expert recommendations to general practice dentists. Journal of Health and Social Behavior 30, 330-43. Levers, B. G. H. & Scully, C. (1986). Antimicrobial prophylaxis of endocarditis: compliance of dental practitioners with British recommendations. Journal of Dental Research 65, Special Issue, 789. Meyer, G. W. (1979). Prophylaxis of infective endocarditis during gastrointestinal procedures: report of a survey. Gastrointestinal Endoscopy 25, 1-2. Michel, M. F. (1986). Review of the guidelines of the Dutch Heart Foundation for the prevention of endocarditis. Nederlands Tijdschrift voor Geneeskunde 130, 2211-12. Murenha, E. & Stein, C. M. (1990). Chemoprophylaxis of bacterial endocarditis—a survey of current practice in Zimbabwe. Journal of Antimicrobial Chemotherapy 25, 291-6. Murrah, V. A., Merry, J. W., Little, J. W. & Jaspers, M. T. (1987). Compliance with guidelines for management of dental school patients susceptible to infective endocarditis. Journal of Dental Education 51, 229-32. Nelson, C. L. & Van Blaricum, C. S. (1989). Physician and dentist compliance with American Heart Association guidelines for prevention of bacterial endocarditis. Journal of the American Dental Association 118, 169-73. Pitcher, D. W., Papouchado, M., Channer, K. S. & James, M. A. (1986). Endocarditis prophylaxis: do patients remember advice and know what to do? British Medical Journal 293, 1539^40. Raby, N. (1988). Radiological awareness of current recommendations on prophylaxis of infective endocarditis. British Journal of Radiology 61, 366-7. Sadowsky, D. & Kunzel, C. (1986). A study of the implementation of endocarditis prevention in patients at risk. New York State Dental Journal 52, 34-7. Sadowsky, D. & Kunzel, C. (1988). Recommendations for prevention of bacterial endocarditis: compliance by dental practitioners. Circulation Tl, 1316-8. Sadowsky, D. & Kunzel, C. (1989). 'Usual and customary' practice versus the recommendations of experts: clinician noncompliance in the prevention of bacterial endocarditis. Journal of American Dental Association 118, 175-80. Scully, C. M. Levers, B. G. H., Griffiths, M. J. & Shirlaw, P. J. (1987). Antimicrobial prophylaxis of infective endocarditis: effect of BSAC recommendations on compliance in general practice. Journal of Antimicrobial Chemotherapy 19, 521-6. Sholler, G. F. & Celermajer, J. M. (1984). Prophylaxis of bacterial endocarditis. Awareness of need. Medical Journal of Australia 140, 650-2. Vickers, D. (1987). Endocarditis prophylaxis: do parents remember advice? British Medical Journal 294, 247.
