INT J TUBERC LUNG DIS 18(3):277–285 © 2014 The Union http://dx.doi.org/10.5588/ijtld.13.0517
Can tuberculosis case finding among health-care seeking adults be improved? Observations from Bissau F. Rudolf,*† T. L. Haraldsdottir,*† M. S. Mendes,* A-J. Wagner,* V. F. Gomes,* P. Aaby,* L. Østergaard,† J. Eugen-Olsen,*‡ C. Wejse*§ * Bandim Health Project, International Network for the Demographic Evaluation of Populations and Their Health in Developing Countries Network, Bissau, Guinea-Bissau; † Department of Infectious Diseases, Aarhus University Hospital, Aarhus, ‡ Clinical Research Centre, Copenhagen University Hospital, Hvidovre, § GloHAU, Center for Global Health, School of Public Health, Aarhus University, Aarhus, Denmark SUMMARY SETTING:
The Bandim Health Project study area in Bissau, Guinea-Bissau. O B J E C T I V E : To assess the potential usefulness of predictors (elsewhere applied) and clinical scores (TBscore and TBscore II) based on signs and symptoms typical of tuberculosis (TB) in case finding. D E S I G N : Observational prospective cohort study of patients with signs and symptoms suggestive of pulmonary TB (PTB) from 2010 to 2012. R E S U LT S : We included 1089 PTB suspects with a mean age of 34 years (95%CI 33–35); human immunodeficiency virus (HIV) prevalence was 15.1%. PTB was diagnosed in 107 suspects (76.4% sputum smear-positive, 25.2% HIV-infected). Cough > 2 weeks had the highest diagnostic ability (area under the receiver operating characteristic curve [AUC] 0.66, 95%CI 0.62–0.71), while TBscore < 3 best excluded PTB (negative likelihood
ratio [LR−] 0.3) when HIV status was not known. TBscore II ⩾ 3 had the highest diagnostic ability in HIVinfected PTB suspects (AUC 0.62, 95%CI 0.53–0.72), while the absence of self-reported weight loss best excluded PTB (LR− 0.2). Cough > 2 weeks as a trigger for smear microscopy missed 32.1% of smear-positive PTB cases. C O N C L U S I O N : Case finding could be improved by screening symptomatic adults for cough and/or weight loss using TBscore II as the trigger for smear microscopy. To suspect PTB only in patients with cough > 2 weeks (non-HIV-infected) or with current cough, fever, weight loss or night sweats (HIV-infected) was not effective in patients whose HIV status was unknown at first visit. K E Y W O R D S : low-resource settings; health status indicator; diagnosis
TUBERCULOSIS (TB) has considerable impact on life and economy, particularly in low-income countries.1 Unfortunately, case detection rates are difficult to measure,2 and early and complete case finding is challenging.3 The World Health Organization (WHO) defines active TB suspects as individuals with cough of >2 weeks, if non-infected with the human immunodeficiency virus (HIV).4 HIV-infected persons who present with current cough, fever, weight loss or night sweats are considered suspects.5 Definitions used in clinical practice range from current cough6 to cough > 2 weeks.7 Combinations of cough > 1 week and other symptoms, including self-reported fever and weight loss, loss of appetite, dyspnoea, chest pain, haemoptysis, night sweats and contact with a TB case,8,9 are also used in diagnosis, as well as symptoms plus abnormal chest radiography (CXR).10 If identified as a PTB suspect, the patient is referred for sputum smear microscopy, the only diagnostic tool
that is widely available.2 Smear microscopy misses up to 50% of cases,11 and even more when referral rates exceed capacity.12 Often no further action is taken when microscopy results are negative. Missed TB cases account for a considerable proportion of avoidable deaths,13 and contribute to ongoing transmission.14 A follow-up study of initially smear-negative PTB suspects in Bissau revealed the need to focus on PTB suspects due to high mortality.15 The current diagnostic approach for PTB suspects16 misses patients,17 and the final diagnosis for initially smear-negative patients is dependent on repeated visits by the patient and suspicion of TB by the health care provider. The aim of the present study was to determine how case finding could be improved by evaluating the screening potential of widely applied predictors and of the TBscore18 and TBscore II,19 clinical scoring systems for typical signs and symptoms of TB that were developed to monitor TB patients on treatment.
Correspondence to: Frauke Rudolf, Bakkedraget 2a 1.tv, 3400 Hillerød, Denmark. Tel: (+245) 689 5169. Fax: (+245) 32 01 672. e-mail: [email protected] Article submitted 19 July 2013. Final version accepted 12 November 2013.
278
The International Journal of Tuberculosis and Lung Disease
STUDY POPULATION AND METHODS Setting The study was conducted at the Bandim Health Project (BHP) area, a health and demographic surveillance site and part of INDEPTH (International Network for the Demographic Evaluation of Populations and Their Health in Developing Countries). BHP covers six suburban districts of Bissau, Guinea-Bissau, with a population of around 100 000. Guinea-Bissau has a TB incidence rate of 238 per 100 000 population.20 TBscore/TBscore II Originally created to monitor TB patients on treatment, TBscore is based on five self-reported symptoms (Table 1; cough, haemoptysis, dyspnoea, chest pain, night sweats) and six clinical signs (pale inferior conjunctivae, tachycardia, positive finding on lung auscultation, temperature >37°C, body mass index [BMI]
Can tuberculosis case finding among health-care seeking adults be improved? Observations from Bissau F. Rudolf,*† T. L. Haraldsdottir,*† M. S. Mendes,* A-J. Wagner,* V. F. Gomes,* P. Aaby,* L. Østergaard,† J. Eugen-Olsen,*‡ C. Wejse*§ * Bandim Health Project, International Network for the Demographic Evaluation of Populations and Their Health in Developing Countries Network, Bissau, Guinea-Bissau; † Department of Infectious Diseases, Aarhus University Hospital, Aarhus, ‡ Clinical Research Centre, Copenhagen University Hospital, Hvidovre, § GloHAU, Center for Global Health, School of Public Health, Aarhus University, Aarhus, Denmark SUMMARY SETTING:
The Bandim Health Project study area in Bissau, Guinea-Bissau. O B J E C T I V E : To assess the potential usefulness of predictors (elsewhere applied) and clinical scores (TBscore and TBscore II) based on signs and symptoms typical of tuberculosis (TB) in case finding. D E S I G N : Observational prospective cohort study of patients with signs and symptoms suggestive of pulmonary TB (PTB) from 2010 to 2012. R E S U LT S : We included 1089 PTB suspects with a mean age of 34 years (95%CI 33–35); human immunodeficiency virus (HIV) prevalence was 15.1%. PTB was diagnosed in 107 suspects (76.4% sputum smear-positive, 25.2% HIV-infected). Cough > 2 weeks had the highest diagnostic ability (area under the receiver operating characteristic curve [AUC] 0.66, 95%CI 0.62–0.71), while TBscore < 3 best excluded PTB (negative likelihood
ratio [LR−] 0.3) when HIV status was not known. TBscore II ⩾ 3 had the highest diagnostic ability in HIVinfected PTB suspects (AUC 0.62, 95%CI 0.53–0.72), while the absence of self-reported weight loss best excluded PTB (LR− 0.2). Cough > 2 weeks as a trigger for smear microscopy missed 32.1% of smear-positive PTB cases. C O N C L U S I O N : Case finding could be improved by screening symptomatic adults for cough and/or weight loss using TBscore II as the trigger for smear microscopy. To suspect PTB only in patients with cough > 2 weeks (non-HIV-infected) or with current cough, fever, weight loss or night sweats (HIV-infected) was not effective in patients whose HIV status was unknown at first visit. K E Y W O R D S : low-resource settings; health status indicator; diagnosis
TUBERCULOSIS (TB) has considerable impact on life and economy, particularly in low-income countries.1 Unfortunately, case detection rates are difficult to measure,2 and early and complete case finding is challenging.3 The World Health Organization (WHO) defines active TB suspects as individuals with cough of >2 weeks, if non-infected with the human immunodeficiency virus (HIV).4 HIV-infected persons who present with current cough, fever, weight loss or night sweats are considered suspects.5 Definitions used in clinical practice range from current cough6 to cough > 2 weeks.7 Combinations of cough > 1 week and other symptoms, including self-reported fever and weight loss, loss of appetite, dyspnoea, chest pain, haemoptysis, night sweats and contact with a TB case,8,9 are also used in diagnosis, as well as symptoms plus abnormal chest radiography (CXR).10 If identified as a PTB suspect, the patient is referred for sputum smear microscopy, the only diagnostic tool
that is widely available.2 Smear microscopy misses up to 50% of cases,11 and even more when referral rates exceed capacity.12 Often no further action is taken when microscopy results are negative. Missed TB cases account for a considerable proportion of avoidable deaths,13 and contribute to ongoing transmission.14 A follow-up study of initially smear-negative PTB suspects in Bissau revealed the need to focus on PTB suspects due to high mortality.15 The current diagnostic approach for PTB suspects16 misses patients,17 and the final diagnosis for initially smear-negative patients is dependent on repeated visits by the patient and suspicion of TB by the health care provider. The aim of the present study was to determine how case finding could be improved by evaluating the screening potential of widely applied predictors and of the TBscore18 and TBscore II,19 clinical scoring systems for typical signs and symptoms of TB that were developed to monitor TB patients on treatment.
Correspondence to: Frauke Rudolf, Bakkedraget 2a 1.tv, 3400 Hillerød, Denmark. Tel: (+245) 689 5169. Fax: (+245) 32 01 672. e-mail: [email protected] Article submitted 19 July 2013. Final version accepted 12 November 2013.
278
The International Journal of Tuberculosis and Lung Disease
STUDY POPULATION AND METHODS Setting The study was conducted at the Bandim Health Project (BHP) area, a health and demographic surveillance site and part of INDEPTH (International Network for the Demographic Evaluation of Populations and Their Health in Developing Countries). BHP covers six suburban districts of Bissau, Guinea-Bissau, with a population of around 100 000. Guinea-Bissau has a TB incidence rate of 238 per 100 000 population.20 TBscore/TBscore II Originally created to monitor TB patients on treatment, TBscore is based on five self-reported symptoms (Table 1; cough, haemoptysis, dyspnoea, chest pain, night sweats) and six clinical signs (pale inferior conjunctivae, tachycardia, positive finding on lung auscultation, temperature >37°C, body mass index [BMI]
