Completeness of tuberculosis case notification in Ghana: record linkage and capture-recapture analysis of three TB registries.

BACKGROUND

In many low and middle-income countries, Tuberculosis (TB) surveillance systems miss out on reporting on detected cases suggesting gaps in the TB case detection and documentation systems. The World Health Organisation estimates that less than half of TB cases in Ghana are notified. Capture-recapture (CR) techniques that involve data linkages have been applied in various settings to estimate the total number of tuberculosis cases, including those unreported. This study evaluated the completeness of reporting of TB in a region of Ghana using CR techniques.

METHODS

We evaluated the completeness of TB case notification data reported between 2016 and 2017 by performing record linkage in five out of 26 districts in the Eastern Region of Ghana. We linked data of all bacteriologically confirmed pulmonary TB (PTB) cases recorded in three registries, namely the district, laboratory, and treatment centre registers, to identify gaps in notification. Regression analysis was used to assess linkages of the three records based on name, age and sex. We estimated overall completeness with log-linear modelling.

RESULTS

There were 2,035 cases across the three registers, of which 773 (38%) were bacteriologically confirmed. The district, laboratory and treatment centre registers had recorded 369 (47.7%), 368 (47.6%) and 404 (52.3%) of the confirmed cases respectively. Only 82 (10.6%) cases were consistent across all three registers. There were 115 (14.9%), 238 (30.8%) and 134 (17.3%) cases that were exclusively in the district, laboratory and treatment centre registers. Log-linear capture-recapture model estimated 2,483 (95%CI: 1,797; 3,813) as expected number of confirmed cases. On that basis, overall completeness of reporting of the district TB registry was 14.9% (369/2,483; 95%CI: 13.5, 16.3).

CONCLUSION

We found low levels of completeness of TB case reporting in the study area. A more wider assessment of the surveillance system in Ghana is needed to identify gaps in reporting.