doi:10.1111/codi.12811
Original article
Diverticular disease in Scotland: 2000–2010 H. M. Paterson*, I. D. Arnott†, R. J. Nicholls‡, D. Clark§, J. Bauer§, P. C. Bridger§, A. M. Crowe¶, A. D. Knight**, P. Hodgkins††, D. Solomon‡‡ and M. G. Dunlop* *Department of Coloproctology, University of Edinburgh, Western General Hospital, Edinburgh, UK, †Department of Gastroenterology, University of Edinburgh, Western General Hospital, Edinburgh, UK, ‡Department of Biosurgery and Surgical Technology, Imperial College, St Mary’s Campus, London, UK, §Information Services Division, NHS National Services Scotland, Edinburgh, UK, ¶Corvus Communications Limited, Buxted, UK, **Evicom Limited, Teddington, UK, ††Global Health Economics and Outcomes Research, Wayne, Pennsylvania, USA and ‡‡Global Medical Affairs, Shire, Wayne, Pennsylvania, USA Received 13 May 2014; accepted 3 September 2014; Accepted Article online 30 October 2014
Abstract Aim Symptomatic diverticular disease (DD) may be increasing in incidence in western society particularly in younger age groups. This study aimed to describe hospital admission rates and management for DD in Scotland between 2000 and 2010. Method Data were obtained from the Scottish Morbidity Records (SMR01). The study cohort included all patients with a hospital admission and a primary diagnosis of DD of the large intestine (ICD-10 primary code K57). Results Scottish NHS hospitals reported 90 990 admissions for DD (in 87 314 patients) from 2000 to 2010. The annual number of admissions increased by 55.2% from 6591 in 2000 to 10,228 in 2010, an average annual increase per year of 4.5%. Most of the increase attributable to DD was due to elective day cases (3618 in 2000; 6925 in 2010) a likely consequence of a greater proportion of the population accessing colonoscopy over that time period. There was an 11% increase in inpatient admissions (2973–3303), 60% of these patients being women. Admissions in younger age
Introduction Diverticular disease (DD) is common in western society. Since colonic diverticulosis may be an incidental finding in colonic investigations for other reasons, accurate epidemiology of the condition is limited. Most published data come from small uncontrolled case series, but recently there has been an increased use of prospective population-based datasets. In England, Hospital Episode Statistics (HES) data analysis estimated an Correspondence to: Hugh M. Paterson, Department of Coloproctology, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK. E-mail: [email protected]
groups increased proportionally in the later years of the study, and there was an association between DD admissions and greater deprivation. Despite an increase in complicated DD from 22.9% in 2000 to 27.1% in 2010 and a 16.8% increase in emergency inpatient admissions, the rate of surgery fell during the period of study. Conclusion This report supports findings of other population-based studies of western countries indicating that DD is an increasing burden on health service resources, particularly in younger age groups. Keywords Diverticulosis, treatment, morbidity, mortality, epidemiology What does this paper add to the literature? As well as demonstrating increased day-case and inpatient admissions for diverticular disease, confirming other recent studies, it provides further evidence that increasingly younger age groups may be affected. Moreover, for the first time we show an association between increased standardized mortality and female gender, younger age, socio-economic deprivation status and emergency surgery.
increased incidence of hospitalization (total inpatient and day-case admissions) for DD from 0.56 to 1.2 per 1000 population/year from 1996 to 2006. Nationwide Inpatient Sample data from the USA were used to estimate a 26% increase in annual age-adjusted admissions for acute diverticulitis (a subgroup of DD characterized by acute inflammation, abdominal pain and systemic response) from 1998 to 2005. These studies have suggested that acute diverticulitis is increasingly affecting younger patients both in the USA and the UK [1–3]. Although surgeons manage most cases of acute diverticulitis and its sequelae, existing management paradigms have recently been challenged. For decades, treatment
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
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Diverticular disease in Scotland: 2000–2010
with antibiotics has been the standard of care for acute uncomplicated diverticulitis, but a recent randomized clinical trial of treatment with or without antibiotics found no difference in length of hospital stay or readmission to hospital with recurrent acute diverticulitis within 1 year [4]. Where emergency surgery is indicated, sigmoid colectomy with colostomy (Hartmann’s procedure) or colectomy with primary anastomosis had been the mainstay of treatment, but recently minimally invasive non-resectional techniques have been used to treat selected patients with perforated diverticulitis [5]. Elective sigmoid resection was recommended after two episodes of acute diverticulitis, but it is now evident that only a small proportion of this group will develop recurrence, hence early prophylactic surgery is not costeffective [6]. Accordingly, professional guidelines for surgery have been revised to reflect a more conservative strategy assessed on a case by case basis [7]. The aim of this study was to describe hospital admission rates and management of DD in Scotland over the last decade to identify any changes in epidemiology, burden to healthcare services and clinical practice.
Method Data were obtained from Scottish Morbidity Records (SMR01), which records all discharges from Scottish NHS hospitals (excluding maternity and psychiatric admissions) and death registrations provided by National Records for Scotland (NRS) which are routinely linked and held as part of the Scottish Linked Acute Dataset (ACaDMe) [8,9]. The combined dataset links patients’ demographic and socioeconomic variables, episode management information and clinical data (e.g. diagnoses, operations or procedures) by a unique patient identifier number. The database is recognized by the International Health Data Linkage Network as one of the longestestablished medical record linkage systems in the world [10]. Quality management of the database by the Information Services Division (ISD), part of NHS National Services Scotland, ensures a level of accuracy of 99% in the linkage of patients’ records [9]. Ethical approval for the study was not required. The study was reviewed and accepted by the Privacy Advisory Committee of ISD NHS National Services Scotland. Data were provided in accordance with the ISD information request protocol. Disclosure control methods, including exclusion of small number data where necessary in tables, were implemented to protect patient confidentiality. The study cohort included all patients with a hospital admission and a primary diagnosis of DD of the large intestine with and without perforation or abscess forma-
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tion as determined by ICD-10 primary code K57 (International Classification of Disease Tenth Edition codes K57.2, K57.3, K57.4, K57.5, K57.8, K57.9) in the period 1 January 2000 to 31 December 2010. Diagnostic codes K57.0 (DD of small intestine with perforation and abscess) and K57.1 (DD of small intestine without perforation or abscess) in any primary or secondary position were excluded. Each hospital admission was defined as a continuous inpatient stay (CIS), which encompassed all admission episodes to allow for interdepartmental and interhospital episode transfers. This ensures that patients are counted only once per admission. Only patients with a primary level DD coding appearing within any episode in the CIS were included in the study cohort. Day cases were defined as patients discharged from hospital before midnight on the day of admission and patients recorded as being managed as day cases. In order to distinguish patients with complicated DD from those with uncomplicated DD, additional coding detail was obtained to augment the K57 code for perforation. Complications were defined as any relevant diagnostic code in positions 1–6 on any episode in the CIS for the following: obstruction, abscess/fistula, peritonitis, abdominal mass, haemorrhage and shock. Data elements extracted for each patient included admission urgency (elective or emergency), patient demographics, length of stay, investigations and procedures. Each CIS was categorized as ‘diagnostic’, ‘medical’ or ‘surgical.’ Diagnostic hospital stays were defined by coding for radiological or endoscopic investigation and the absence of coding for surgical interventions. Surgical CISs were defined by the presence of any OPCS-4 Classification of Interventions and Procedures code for an appropriate surgical intervention in any position on the SMR01 whether or not a diagnostic test was performed. Patient demographics included age, gender and deprivation status. Age at admission was categorized as < 45, 45–54, 55–64, 65–74, 75–84 and 85+ years. Deprivation scores were calculated using the Scottish Index of Multiple Deprivation (SIMD) 2009, a tool combining 38 indicators across eight domains including income, employment, health, education, skills and training, housing, geographical access and crime to identify small-area concentrations of multiple deprivation across Scotland. SIMD was categorized into quintiles, with one being most deprived and five most affluent. Standardized mortality ratios (SMRs) were calculated by comparing deaths per person year at risk with the Scottish reference population and mortality data by age group and gender for each treatment subcohort.
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
H. M. Paterson et al.
Diverticular disease in Scotland: 2000–2010
8000
Statistical analysis
Elective day case Elective inpatient Emergency
7000
Ninety-five per cent confidence intervals were calculated assuming a Poisson distribution for observed numbers of deaths. Mortality was defined as death from any cause up to the end of 2010. Percentage differences across categorizations of age group, gender and deprivation were assessed for statistical significance using chisquare tests and differences in mean age using t-tests. Statistical analysis was performed using SPSS 17.0 (IBM, New York, NY, USA) and Microsoft Excel 2003 (Microsoft, Redmond, WA, USA).
Results There were 90 990 admissions for DD to Scottish NHS hospitals (in 87 314 patients) from 2000 to 2010. The annual number of admissions increased from 6591 in 2000 to 10 228 in 2010, an increase throughout the period of 55.2% and an average annual increase per year of 4.5%. By comparison, admissions over the same time period for all digestive diseases increased by 10.8% and all-causes hospital admissions increased by 5.2% (Fig. 1). Most of the increase in DD hospital admissions was due to an increase in elective day-case admissions (3618 in 2000; 6925 in 2010). Elective inpatient admissions remained constant at approximately 900 per year. These figures were mirrored almost exactly by greatly increased numbers of day-case colonoscopies, which rose from 3677 in 2000 to 6898 in 2010, and stable inpatient colonoscopies (950 in 2000; 1046 in 2010). Emergency admissions increased by 16.8% from 2059 in 2000 to 2404 in 2010 (Fig. 2). Inpatient bed occupancy totalled 254 945 bed-days, of which intensive care occupancy comprised 15 626 days. The median length of stay for inpatient admissions ranged from 4 days for patients treated non-
6000 5000 4000 3000 2000 1000 0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years
Figure 2 Elective and emergency admissions with diverticular disease to Scottish NHS hospitals, 2000–2010.
surgically to 11 and 13 days, respectively, for those having surgery for uncomplicated and complicated DD. Age and gender
More women than men were admitted throughout the period of study (62.3% in 2000; 59.4% in 2010; P < 0.001). The mean age of DD inpatient admissions did not change significantly for patients managed by surgery [64.2 years (SD 13.4) in 2000; 62.9 years (SD 13.1) in 2010, P = 0.136] but fell significantly for patients managed non-surgically (mean 69.5 years [SD 13.8] to 65.3 years [SD 15.3]; P < 0.001). The proportion of inpatient admissions in patients below 65 years of age increased from 34.9% in 2000 to 40.7% in 2010 (Fig. 3). In patients requiring surgery, the proportion aged 55–64 years increased from 19.2 to 28.5% (P = 0.001; Fig. 4). Deprivation
The distribution of deprivation scores did not differ substantially during the period of the study. There was a clear association between greater deprivation < 45
45–54
55–64
65–74
75–84
85+
1500 Increase in continuous inpatient stays (%)
60.0 50.0
Diverticular disease Digestive diseases All hospital admissions 1000
40.0 30.0 20.0
500 10.0 0.0
–10.0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Calendar year
Figure 1 Percentage change in diverticular disease, digestive diseases and all hospital admissions in Scotland, 2000–2010.
0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years
Figure 3 All inpatient diverticular disease by age group in Scotland, 2000–2010.
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
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Diverticular disease in Scotland: 2000–2010
< 45
45–54
55–64
65–74
75–84
85+
160 140 120 100 80 60 40 20 0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years
Figure 4 Inpatient admissions for diverticular disease treated by surgery by age group, 2000–2010.
(1 = most deprived, 5 = most affluent) by SIMD quintile and rate of hospitalization as follows: 1, 24.0%; 2, 23.2%; 3, 20.1%; 4, 16.9%; 5, 15.8% (P < 0.001). Mortality
Table 1 compares SMRs for elective and emergency patients managed operatively with the remainder of the total cohort (day case and inpatient). Consistent factors associated with excess of mortality compared to the general population were female gender (operated cases), greater deprivation, younger age and emergency surgery. Statistical comparisons cannot be made between SMRs from different groups, but SMRs were numerically higher in younger rather than older patient groups for elective and emergency surgery with no clear pattern by age group for non-operative admissions [11,12]. Surgery
Although the total number of emergency inpatient admissions increased steadily, the absolute number of operations did not change, and hence the rate of surgery among emergency inpatient admissions fell (Fig. 5). This was not attributable to milder disease since the proportion of DD inpatient admissions coded as complicated increased from 22.9% in 2000 to 27.1% in 2010 (Fig. 5). The absolute number of elective operations for DD over the decade remained constant (207 in 2000; 201 in 2010).
Discussion Using national data to draw conclusions on the epidemiology of DD, a common condition which for many patients is an incidental finding, has limitations. Unfortunately, current coding does not allow truly symptomatic DD to be distinguished from incidental
332
diverticulosis. This discrepancy is more likely in the elective than the emergency setting. In this study, elective day-case and inpatient admissions to Scottish hospitals with a primary coding for DD increased substantially in the past decade, in keeping with other UK population-based datasets [2]. Increased access to colonoscopy is the obvious explanation for the large increase in coding of DD in these groups. The increase in DD-coded emergency inpatient admissions of 16.8% over 11 years is, however, less likely to be explained by increased colonoscopy. It is reasonable to assume that most of these admissions were due to acute diverticulitis. This figure is comparable to the 26% increase in acute diverticulitis admissions to US hospitals observed between 1998 and 2005 [3]. In our study the greatest increase in admissions over time was in patients under the age of 65 years. This mirrors the data of Etzioni et al. [1,3], which showed that the greatest increase in population-adjusted admissions for acute diverticulitis in California and the USA occurred in the youngest age groups. A study of more recent NIS data (2002–2007) comprising more than a million admissions reported the greatest increase in admissions in patients aged 50–70 years and a comparatively smaller increase in patients younger than 50. However, their data included elective admissions (21.7% of the cohort) and hence it was not a comparable study of acute diverticulitis [13]. This trend could be due to a truly increased incidence in symptomatic DD, to increased diagnosis or to a lower threshold for hospital admission. Given the association of DD with obesity and a sedentary lifestyle, both of which are increasingly prevalent in younger age groups in western societies, it is possible that the burden to healthcare services from DD may increase in the coming decades. There are few published data examining the association of deprivation with DD. In this study, hospital admission was more likely and hospital stay was longer in deprived compared with affluent populations. SMRs showed that DD was associated with an excess of mortality compared with the general population that was higher in deprived compared with affluent populations. An association of deprivation with diagnosis of DD was observed in a recent prospective UK cohort study [14] and the results of treatment for DD were inferior in deprived patients in a study from New York State, USA [15]. The association of deprivation with many of the risk factors for DD, including obesity, a low-fibre diet, smoking and little exercise, is well established [16–18]. An unexpected finding in this DD cohort was the association of female gender and younger age with an excess mortality compared with the general population. It is not appropriate to use SMRs to compare with other
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
H. M. Paterson et al.
Diverticular disease in Scotland: 2000–2010
Table 1 Standardised Mortality Ratio (SMR) among patients having a first admission for diverticular disease. Primary management
Sub-group
Admission route Elective N
Operative
Non-operative
Overall Age (years)
Original article
Diverticular disease in Scotland: 2000–2010 H. M. Paterson*, I. D. Arnott†, R. J. Nicholls‡, D. Clark§, J. Bauer§, P. C. Bridger§, A. M. Crowe¶, A. D. Knight**, P. Hodgkins††, D. Solomon‡‡ and M. G. Dunlop* *Department of Coloproctology, University of Edinburgh, Western General Hospital, Edinburgh, UK, †Department of Gastroenterology, University of Edinburgh, Western General Hospital, Edinburgh, UK, ‡Department of Biosurgery and Surgical Technology, Imperial College, St Mary’s Campus, London, UK, §Information Services Division, NHS National Services Scotland, Edinburgh, UK, ¶Corvus Communications Limited, Buxted, UK, **Evicom Limited, Teddington, UK, ††Global Health Economics and Outcomes Research, Wayne, Pennsylvania, USA and ‡‡Global Medical Affairs, Shire, Wayne, Pennsylvania, USA Received 13 May 2014; accepted 3 September 2014; Accepted Article online 30 October 2014
Abstract Aim Symptomatic diverticular disease (DD) may be increasing in incidence in western society particularly in younger age groups. This study aimed to describe hospital admission rates and management for DD in Scotland between 2000 and 2010. Method Data were obtained from the Scottish Morbidity Records (SMR01). The study cohort included all patients with a hospital admission and a primary diagnosis of DD of the large intestine (ICD-10 primary code K57). Results Scottish NHS hospitals reported 90 990 admissions for DD (in 87 314 patients) from 2000 to 2010. The annual number of admissions increased by 55.2% from 6591 in 2000 to 10,228 in 2010, an average annual increase per year of 4.5%. Most of the increase attributable to DD was due to elective day cases (3618 in 2000; 6925 in 2010) a likely consequence of a greater proportion of the population accessing colonoscopy over that time period. There was an 11% increase in inpatient admissions (2973–3303), 60% of these patients being women. Admissions in younger age
Introduction Diverticular disease (DD) is common in western society. Since colonic diverticulosis may be an incidental finding in colonic investigations for other reasons, accurate epidemiology of the condition is limited. Most published data come from small uncontrolled case series, but recently there has been an increased use of prospective population-based datasets. In England, Hospital Episode Statistics (HES) data analysis estimated an Correspondence to: Hugh M. Paterson, Department of Coloproctology, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK. E-mail: [email protected]
groups increased proportionally in the later years of the study, and there was an association between DD admissions and greater deprivation. Despite an increase in complicated DD from 22.9% in 2000 to 27.1% in 2010 and a 16.8% increase in emergency inpatient admissions, the rate of surgery fell during the period of study. Conclusion This report supports findings of other population-based studies of western countries indicating that DD is an increasing burden on health service resources, particularly in younger age groups. Keywords Diverticulosis, treatment, morbidity, mortality, epidemiology What does this paper add to the literature? As well as demonstrating increased day-case and inpatient admissions for diverticular disease, confirming other recent studies, it provides further evidence that increasingly younger age groups may be affected. Moreover, for the first time we show an association between increased standardized mortality and female gender, younger age, socio-economic deprivation status and emergency surgery.
increased incidence of hospitalization (total inpatient and day-case admissions) for DD from 0.56 to 1.2 per 1000 population/year from 1996 to 2006. Nationwide Inpatient Sample data from the USA were used to estimate a 26% increase in annual age-adjusted admissions for acute diverticulitis (a subgroup of DD characterized by acute inflammation, abdominal pain and systemic response) from 1998 to 2005. These studies have suggested that acute diverticulitis is increasingly affecting younger patients both in the USA and the UK [1–3]. Although surgeons manage most cases of acute diverticulitis and its sequelae, existing management paradigms have recently been challenged. For decades, treatment
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
329
Diverticular disease in Scotland: 2000–2010
with antibiotics has been the standard of care for acute uncomplicated diverticulitis, but a recent randomized clinical trial of treatment with or without antibiotics found no difference in length of hospital stay or readmission to hospital with recurrent acute diverticulitis within 1 year [4]. Where emergency surgery is indicated, sigmoid colectomy with colostomy (Hartmann’s procedure) or colectomy with primary anastomosis had been the mainstay of treatment, but recently minimally invasive non-resectional techniques have been used to treat selected patients with perforated diverticulitis [5]. Elective sigmoid resection was recommended after two episodes of acute diverticulitis, but it is now evident that only a small proportion of this group will develop recurrence, hence early prophylactic surgery is not costeffective [6]. Accordingly, professional guidelines for surgery have been revised to reflect a more conservative strategy assessed on a case by case basis [7]. The aim of this study was to describe hospital admission rates and management of DD in Scotland over the last decade to identify any changes in epidemiology, burden to healthcare services and clinical practice.
Method Data were obtained from Scottish Morbidity Records (SMR01), which records all discharges from Scottish NHS hospitals (excluding maternity and psychiatric admissions) and death registrations provided by National Records for Scotland (NRS) which are routinely linked and held as part of the Scottish Linked Acute Dataset (ACaDMe) [8,9]. The combined dataset links patients’ demographic and socioeconomic variables, episode management information and clinical data (e.g. diagnoses, operations or procedures) by a unique patient identifier number. The database is recognized by the International Health Data Linkage Network as one of the longestestablished medical record linkage systems in the world [10]. Quality management of the database by the Information Services Division (ISD), part of NHS National Services Scotland, ensures a level of accuracy of 99% in the linkage of patients’ records [9]. Ethical approval for the study was not required. The study was reviewed and accepted by the Privacy Advisory Committee of ISD NHS National Services Scotland. Data were provided in accordance with the ISD information request protocol. Disclosure control methods, including exclusion of small number data where necessary in tables, were implemented to protect patient confidentiality. The study cohort included all patients with a hospital admission and a primary diagnosis of DD of the large intestine with and without perforation or abscess forma-
330
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tion as determined by ICD-10 primary code K57 (International Classification of Disease Tenth Edition codes K57.2, K57.3, K57.4, K57.5, K57.8, K57.9) in the period 1 January 2000 to 31 December 2010. Diagnostic codes K57.0 (DD of small intestine with perforation and abscess) and K57.1 (DD of small intestine without perforation or abscess) in any primary or secondary position were excluded. Each hospital admission was defined as a continuous inpatient stay (CIS), which encompassed all admission episodes to allow for interdepartmental and interhospital episode transfers. This ensures that patients are counted only once per admission. Only patients with a primary level DD coding appearing within any episode in the CIS were included in the study cohort. Day cases were defined as patients discharged from hospital before midnight on the day of admission and patients recorded as being managed as day cases. In order to distinguish patients with complicated DD from those with uncomplicated DD, additional coding detail was obtained to augment the K57 code for perforation. Complications were defined as any relevant diagnostic code in positions 1–6 on any episode in the CIS for the following: obstruction, abscess/fistula, peritonitis, abdominal mass, haemorrhage and shock. Data elements extracted for each patient included admission urgency (elective or emergency), patient demographics, length of stay, investigations and procedures. Each CIS was categorized as ‘diagnostic’, ‘medical’ or ‘surgical.’ Diagnostic hospital stays were defined by coding for radiological or endoscopic investigation and the absence of coding for surgical interventions. Surgical CISs were defined by the presence of any OPCS-4 Classification of Interventions and Procedures code for an appropriate surgical intervention in any position on the SMR01 whether or not a diagnostic test was performed. Patient demographics included age, gender and deprivation status. Age at admission was categorized as < 45, 45–54, 55–64, 65–74, 75–84 and 85+ years. Deprivation scores were calculated using the Scottish Index of Multiple Deprivation (SIMD) 2009, a tool combining 38 indicators across eight domains including income, employment, health, education, skills and training, housing, geographical access and crime to identify small-area concentrations of multiple deprivation across Scotland. SIMD was categorized into quintiles, with one being most deprived and five most affluent. Standardized mortality ratios (SMRs) were calculated by comparing deaths per person year at risk with the Scottish reference population and mortality data by age group and gender for each treatment subcohort.
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
H. M. Paterson et al.
Diverticular disease in Scotland: 2000–2010
8000
Statistical analysis
Elective day case Elective inpatient Emergency
7000
Ninety-five per cent confidence intervals were calculated assuming a Poisson distribution for observed numbers of deaths. Mortality was defined as death from any cause up to the end of 2010. Percentage differences across categorizations of age group, gender and deprivation were assessed for statistical significance using chisquare tests and differences in mean age using t-tests. Statistical analysis was performed using SPSS 17.0 (IBM, New York, NY, USA) and Microsoft Excel 2003 (Microsoft, Redmond, WA, USA).
Results There were 90 990 admissions for DD to Scottish NHS hospitals (in 87 314 patients) from 2000 to 2010. The annual number of admissions increased from 6591 in 2000 to 10 228 in 2010, an increase throughout the period of 55.2% and an average annual increase per year of 4.5%. By comparison, admissions over the same time period for all digestive diseases increased by 10.8% and all-causes hospital admissions increased by 5.2% (Fig. 1). Most of the increase in DD hospital admissions was due to an increase in elective day-case admissions (3618 in 2000; 6925 in 2010). Elective inpatient admissions remained constant at approximately 900 per year. These figures were mirrored almost exactly by greatly increased numbers of day-case colonoscopies, which rose from 3677 in 2000 to 6898 in 2010, and stable inpatient colonoscopies (950 in 2000; 1046 in 2010). Emergency admissions increased by 16.8% from 2059 in 2000 to 2404 in 2010 (Fig. 2). Inpatient bed occupancy totalled 254 945 bed-days, of which intensive care occupancy comprised 15 626 days. The median length of stay for inpatient admissions ranged from 4 days for patients treated non-
6000 5000 4000 3000 2000 1000 0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years
Figure 2 Elective and emergency admissions with diverticular disease to Scottish NHS hospitals, 2000–2010.
surgically to 11 and 13 days, respectively, for those having surgery for uncomplicated and complicated DD. Age and gender
More women than men were admitted throughout the period of study (62.3% in 2000; 59.4% in 2010; P < 0.001). The mean age of DD inpatient admissions did not change significantly for patients managed by surgery [64.2 years (SD 13.4) in 2000; 62.9 years (SD 13.1) in 2010, P = 0.136] but fell significantly for patients managed non-surgically (mean 69.5 years [SD 13.8] to 65.3 years [SD 15.3]; P < 0.001). The proportion of inpatient admissions in patients below 65 years of age increased from 34.9% in 2000 to 40.7% in 2010 (Fig. 3). In patients requiring surgery, the proportion aged 55–64 years increased from 19.2 to 28.5% (P = 0.001; Fig. 4). Deprivation
The distribution of deprivation scores did not differ substantially during the period of the study. There was a clear association between greater deprivation < 45
45–54
55–64
65–74
75–84
85+
1500 Increase in continuous inpatient stays (%)
60.0 50.0
Diverticular disease Digestive diseases All hospital admissions 1000
40.0 30.0 20.0
500 10.0 0.0
–10.0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Calendar year
Figure 1 Percentage change in diverticular disease, digestive diseases and all hospital admissions in Scotland, 2000–2010.
0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years
Figure 3 All inpatient diverticular disease by age group in Scotland, 2000–2010.
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
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< 45
45–54
55–64
65–74
75–84
85+
160 140 120 100 80 60 40 20 0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years
Figure 4 Inpatient admissions for diverticular disease treated by surgery by age group, 2000–2010.
(1 = most deprived, 5 = most affluent) by SIMD quintile and rate of hospitalization as follows: 1, 24.0%; 2, 23.2%; 3, 20.1%; 4, 16.9%; 5, 15.8% (P < 0.001). Mortality
Table 1 compares SMRs for elective and emergency patients managed operatively with the remainder of the total cohort (day case and inpatient). Consistent factors associated with excess of mortality compared to the general population were female gender (operated cases), greater deprivation, younger age and emergency surgery. Statistical comparisons cannot be made between SMRs from different groups, but SMRs were numerically higher in younger rather than older patient groups for elective and emergency surgery with no clear pattern by age group for non-operative admissions [11,12]. Surgery
Although the total number of emergency inpatient admissions increased steadily, the absolute number of operations did not change, and hence the rate of surgery among emergency inpatient admissions fell (Fig. 5). This was not attributable to milder disease since the proportion of DD inpatient admissions coded as complicated increased from 22.9% in 2000 to 27.1% in 2010 (Fig. 5). The absolute number of elective operations for DD over the decade remained constant (207 in 2000; 201 in 2010).
Discussion Using national data to draw conclusions on the epidemiology of DD, a common condition which for many patients is an incidental finding, has limitations. Unfortunately, current coding does not allow truly symptomatic DD to be distinguished from incidental
332
diverticulosis. This discrepancy is more likely in the elective than the emergency setting. In this study, elective day-case and inpatient admissions to Scottish hospitals with a primary coding for DD increased substantially in the past decade, in keeping with other UK population-based datasets [2]. Increased access to colonoscopy is the obvious explanation for the large increase in coding of DD in these groups. The increase in DD-coded emergency inpatient admissions of 16.8% over 11 years is, however, less likely to be explained by increased colonoscopy. It is reasonable to assume that most of these admissions were due to acute diverticulitis. This figure is comparable to the 26% increase in acute diverticulitis admissions to US hospitals observed between 1998 and 2005 [3]. In our study the greatest increase in admissions over time was in patients under the age of 65 years. This mirrors the data of Etzioni et al. [1,3], which showed that the greatest increase in population-adjusted admissions for acute diverticulitis in California and the USA occurred in the youngest age groups. A study of more recent NIS data (2002–2007) comprising more than a million admissions reported the greatest increase in admissions in patients aged 50–70 years and a comparatively smaller increase in patients younger than 50. However, their data included elective admissions (21.7% of the cohort) and hence it was not a comparable study of acute diverticulitis [13]. This trend could be due to a truly increased incidence in symptomatic DD, to increased diagnosis or to a lower threshold for hospital admission. Given the association of DD with obesity and a sedentary lifestyle, both of which are increasingly prevalent in younger age groups in western societies, it is possible that the burden to healthcare services from DD may increase in the coming decades. There are few published data examining the association of deprivation with DD. In this study, hospital admission was more likely and hospital stay was longer in deprived compared with affluent populations. SMRs showed that DD was associated with an excess of mortality compared with the general population that was higher in deprived compared with affluent populations. An association of deprivation with diagnosis of DD was observed in a recent prospective UK cohort study [14] and the results of treatment for DD were inferior in deprived patients in a study from New York State, USA [15]. The association of deprivation with many of the risk factors for DD, including obesity, a low-fibre diet, smoking and little exercise, is well established [16–18]. An unexpected finding in this DD cohort was the association of female gender and younger age with an excess mortality compared with the general population. It is not appropriate to use SMRs to compare with other
Colorectal Disease ª 2014 The Association of Coloproctology of Great Britain and Ireland. 17, 329–334
H. M. Paterson et al.
Diverticular disease in Scotland: 2000–2010
Table 1 Standardised Mortality Ratio (SMR) among patients having a first admission for diverticular disease. Primary management
Sub-group
Admission route Elective N
Operative
Non-operative
Overall Age (years)
