Cost-Effectiveness of Follow-Up of Chronic Coughers in Detecting Smear-Positive Tuberculosis in South Ethiopia

Introduction

In Ethiopia, no studies assessing the cost-effectiveness of follow-up of smear-negative chronic coughers in detecting smear-positive tuberculosis (TB) (PTB+) cases have been reported.

Objective

This article describes the cost-effectiveness of community-based follow-up of smear-negative chronic coughers in detecting PTB+ cases.

Methods

Two alternative strategies of TB case finding, namely community-based follow-up of smear-negative chronic coughers and passive TB case finding, were compared. Participants were selected randomly in the active TB case finding approach, while purposively in the passive TB case finding strategy. In November 2012 and January 2015, costs related to TB diagnosis were collected using structured questionnaires from sample of 60 patients in each strategy. Data on health system cost and direct and indirect costs incurred by patients and their caretakers were collected in Ethiopian Birr and converted into USD for analysis. Exchange rate for the data collection period of chronic coughers was 1 USD = 18.16 ETB and for passive case finding period was 1 USD = 20.24 ETB. Cost-effectiveness was calculated in terms of cost per PTB+ cases detected.

Results

The overall cost of TB case finding was lower under active case finding approach than under passive TB case finding approach (USD 27.4 vs. 27.6). Active case finding approach was cost-effective by 43.4% and it is highly cost-effective when the duration of follow-up is reduced to 7 months or less.

Conclusion

Active case finding approach is a cost-effective approach of TB case finding. The cost benefit obtained could be even higher when the follow-up duration is minimized.

Misdiagnosis of pulmonary tuberculosis and associated factors in peripheral laboratories: a retrospective study, Addis Ababa, Ethiopia

Objective

Sputum smear microscopy reading errors are likely to result in failure to detect persons with infectious TB. This study was intended to review misdiagnosis of pulmonary TB and associated factors in peripheral laboratories.

Results

During the study period 1033 (10.5%) sputum smear positive and 8783 (89.5%) smear negative slides were reported by peripheral laboratories. The slides were re-read by the central referral laboratories (CRLs) as the reference standard reading. Of 1033 positive slides reported by peripheral laboratories, 25 (2.4%) were false positive. Out of 8783 smear negative slides reported by peripheral laboratories, 35 (0.4%) were false negative. The sensitivity, specificity, positive predictive value and negative predictive value of peripheral laboratories were 96.64, 99.72, 97.58, and 99.61% respectively. The peripheral laboratories and CRLs have an observed agreement (Po) of 0.9939. Of 135 peripheral laboratories, 93 (68.9%) read negative and positive slides correctly, 49 (36.3%) did not have lens cleaning tissue papers, 11 (8.1%) lacked frosted slides, and 14 (10.4%) had shortage of reagents. As conclusions, the peripheral laboratories and CRLs had high agreement for sputum smear microscopy reading. However, a few TB cases were misdiagnosed despite having the disease; these individuals might continue to spread the infection in the community.

Performance evaluation of tuberculosis smear microscopists working at rechecking laboratories in Ethiopia

Background

Tuberculosis is an infectious disease caused by the bacillus Mycobacterium tuberculosis. According to the Ethiopian Federal Ministry of Health’s 2013–2014 report, the tuberculosis case detection rate was 53.7%, which was below the target of 81% set for that year.

Objective

This study assessed the performance of tuberculosis smear microscopists at external quality assessment rechecking laboratories in Ethiopia.

Methods

A cross-sectional study was conducted at 81 laboratories from April to July 2015. Panel slides were prepared and validated at the National Tuberculosis Reference Laboratory. The validated panel slides were used to evaluate the performance of microscopists at these laboratories compared with readers from the reference laboratory.

Results

A total of 389 external quality assessment rechecking laboratory microscopists participated in the study, of which 268 (68.9%) worked at hospitals, 241 (62%) had more than five years of work experience, 201 (51.7%) held Bachelors degrees, and 319 (82%) reported tuberculosis smear microscopy training. Overall, 324 (83.3%) participants scored ≥ 80%. Sensitivity for detecting tuberculosis bacilli was 84.5% and specificity was 93.1%. The overall percent agreement between participants and reference readers was 87.1 (kappa=0.72). All 10 slides were correctly read (i.e., scored 100%) by 80 (20.6%) participants, 156 (40.1%) scored 90% – 95%, 88 (22.6%) scored 80% – 85% and 65 (16.7%) scored below 80%. There were 806 (20.7%) total errors, with 143 (3.7%) major and 663 (17%) minor errors.

Conclusion

The overall performance of participants in reading the slides showed good agreement with the reference readers. Most errors were minor, and the ability to detect tuberculosis bacilli can be improved through building the capacity of professionals.

External quality assessment for acid fast bacilli smear microscopy in eastern part of Ethiopia

Background

External quality assessment (EQA) of sputum smear microscopy is essential and indispensable component of any tuberculosis program. This study assessed the EQA of acid fast bacilli (AFB) smear microscopy through onsite evaluation, blinded rechecking and panel test. A one year study was conducted on eight health institution laboratories from December 2011 to December 2012. Onsite evaluation, blinded rechecking and panel tests were used to collect data. Data were analyzed using SPSS version 16. Sensitivity, specificity, predictive values, and proportions of false readings were calculated. The level of agreement was measured using Kappa (κ) value.

Results

Problems observed during onsite evaluation include shortages of materials, disinfectant, and poor storage and working condition. A total of 578 slides were collected for blinded rechecking, of which 102 (17.6 %) were reported as positive by peripheral laboratories. The panel test revealed an overall error of 17 (25.25 %) of which 14 (17.5 %) were minor errors [low false negative 6 (7.5 %) and low false positive 8 (10 %)], and 3 (3.75 %) were major errors (high false positive). The sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) of the peripheral laboratories were 83.5, 97.8, 91.7, and 95.7, respectively. The false readings at the peripheral laboratories were 32 (5.5 %). Agreement on reading the slides was observed on 546 (94.5 %) slides (K = 0.84, SE = 0.054).

Conclusions

Lack of reagents, supplies, favorable working environment and AFB related technical problems were identified in the peripheral laboratories. High false negative error was found to be the predominant major error. A continuous and strong EQA scheme should be implemented to avoid reporting errors and produce quality sputum results.

Low case notification rates of childhood tuberculosis in southern Ethiopia

Background

Childhood tuberculosis (TB) is a public health concern causing considerable mortality. However, control of childhood TB receives little attention. The control efforts could be inadequate because of challenges associated with difficulties in diagnosing the disease in children. Understanding the burden of the disease among children is important to assess the ongoing transmission of the disease in a community and improving TB control efforts. This study was carried out to assess TB case notification rates (CNRs) and treatment outcomes in children aged less than 15 years over a ten-year period.

Methods

Data were collected from unit TB registers from all health facilities providing TB treatment in the Sidama Zone in Ethiopia. We analysed the CNRs and treatment outcomes by age category, gender, and place of residence. We used logistic regression analysis to identify factors associated with treatment outcomes and to control for confounding.

Results

A total of 4,656 cases of children less than 15 years of age were notified as diagnosed and treated for TB, constituting 13 % of all notified TB cases in the study area. The mean CNRs per 100,000 children less than 15 years were 30 for all new cases of TB, 28 for rural cases, 67 for urban cases, 28 in boys, and 32 in girls. The proportions of treatment success were 82 % for new and 77 % for retreatment cases for the entire study period and increased to 93 % for new cases in 2012 (X²_trend, P < 0.001). Children less than five years old had a lower treatment success [adjusted odds ratio (AOR) 0.64 (95 % CI, 0.52-0.80)] and higher deaths [AOR 2 (95 % CI, 1.27–3.12)]. The proportion of children who died during treatment among children in the less than 2-year-old age group was three times higher than children in the 2 year and above age groups [AOR 3.34 (95 % CI, 1.92–5.82)].

Conclusion

The CNRs of childhood TB were low in Sidama. Children less than 5 years old had a higher proportion of deaths. Efforts need to be made to improve the diagnosis and treatment of TB among children.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0461-1) contains supplementary material, which is available to authorized users.

The quality of sputum smear microscopy in public-private mix directly observed treatment laboratories in West Amhara region, Ethiopia

Ethiopia adopted Public-Private Mix Directly Observed Treatment Short Course Chemotherapy (PPM-DOTS) strategy for tuberculosis (TB) control program. Quality of sputum smear microscopy has paramount importance for tuberculosis control program in resource-poor countries like Ethiopia. A cross-sectional study was conducted to assess the quality of sputum smear microscopy in 37 Public-Private Mix laboratories in West Amhara, Ethiopia. The three external quality assessment methods (onsite evaluation, panel testing and blind rechecking) were employed. Onsite assessment revealed that 67.6% of PPM-DOTS laboratories were below the standard physical space (5 X 6) m². The average monthly workload per laboratory technician was 19.5 (SD±2.9) slides with 12.8% positivity rate. The quality of Acid Fast Bacilli (AFB) staining reagents was sub-standard. The overall agreement for blind rechecking of 1,123 AFB slides was 99.4% (Kappa = 0.97). Reading of 370 AFB panel slides showed 3.5% false reading (Kappa = 0.92). Moreover, the consistency of reading scanty bacilli slides was lower (93%) compared to 1+, 2+ and 3+ bacilli. Based on blind rechecking and panel testing results, PPM-DOTS site laboratories showed good agreement with the reference laboratory. Physical space and qualities of AFB reagents would be areas of intervention to sustain the quality of sputum smear microscopy. Therefore, regular external quality assessment and provision of basic laboratory supplies for TB diagnosis would be the way forward to improve the quality of sputum smear microscopy services in PPM-DOTS laboratories.

Follow-up of chronic coughers improves tuberculosis case finding: results from a community-based cohort study in southern Ethiopia

BACKGROUND

Untreated smear-positive tuberculosis (TB) patients are the primary source of infection; however, a large number of TB cases have not been identified and are untreated in many sub-Saharan African countries, including Ethiopia. This study determined whether or not a community-based follow-up of chronic coughers improves detection of TB cases and the risk factors for death among such cases.

METHODS

We conducted a census in six rural communities in Sidama, southern Ethiopia. Based on interview and sputum investigation, we identified 724 TB smear-negative chronic coughers, and did a cohort study of these chronic coughers and 1448 neighbourhood controls. For both chronic coughers and neighbourhood controls, we conducted a TB screening interview and performed sputum microscopy, as required, at 4, 7 and 10 months. Between September 2011 and June 2012, we followed chronic coughers and neighbourhood controls for 588 and 1,204 person-years of observation, respectively.

RESULTS

Of the chronic coughers, 23 developed smear-positive TB (incidence rate = 3912/105 person-years) compared to three neighbourhood controls who developed smear-positive TB (incidence rate = 249/105 person-years). The male-to-female ratio of smear-positive TB was 1:1. We demonstrated that chronic coughers (adjusted hazards ratio [aHR], 13.5; 95% CI, 4.0-45.7) and the poor (aHR, 2.6; 95% CI, 1.1-5.8) were at high-risk for smear-positive TB. Among the study cohort, 15 chronic coughers and two neighbourhood controls died (aHR, 14.0; 95% CI, 3.2-62.4).

CONCLUSION

A community-based follow-up of chronic coughers is helpful in improving smear-positive TB case detection, it benefits socioeconomically disadvantaged people in particular; in rural settings, chronic coughers had a higher risk of death.

Trends of tuberculosis case notification and treatment outcomes in the Sidama Zone, southern Ethiopia: ten-year retrospective trend analysis in urban-rural settings

Background

Ethiopia is one of the high tuberculosis (TB) burden countries. An analysis of trends and differentials in case notifications and treatment outcomes of TB may help improve our understanding of the performance of TB control services.

Methods

A retrospective trend analysis of TB cases was conducted in the Sidama Zone in southern Ethiopia. We registered all TB cases diagnosed and treated during 2003–2012 from all health facilities in the Sidama Zone, and analysed trends of TB case notification rates and treatment outcomes.

Results

The smear positive (PTB+) case notification rate (CNR) increased from 55 (95% CI 52.5–58.4) to 111 (95% CI 107.4–114.4) per 10⁵ people. The CNRs of PTB+ in people older than 45 years increased by fourfold, while the mortality of cases during treatment declined from 11% to 3% for smear negative (PTB-) (X²_trend, P<0.001) and from 5% to 2% for PTB+ (X²_trend, P<0.001). The treatment success was higher in rural areas (AOR 1.11; CI 95%: 1.03–1.2), less for PTB- (AOR 0.86; CI 95%: 0.80–0.92) and higher for extra-pulmonary TB (AOR 1.10; CI 95%: 1.02–1.19) compared to PTB+. A higher lost-to-follow up was observed in men (AOR 1.15; CI 95%: 1.06–1.24) and among PTB- cases (AOR 1.14; CI 95%: 1.03–1.25). More deaths occurred in PTB-cases (AOR 1.65; 95% CI: 1.44–1.90) and among cases older than 65 years (AOR 3.86; CI 95%: 2.94–5.10). Lastly, retreatment cases had a higher mortality than new cases (6% vs 3%).

Conclusion

Over the past decade TB CNRs and treatment outcomes improved, whereas the disparities of disease burden by gender and place of residence reduced and mortality declined. Strategies should be devised to address higher risk groups for poor treatment outcomes.