Abstract
BACKGROUND: Although an estimated three million tuberculosis (TB) cases worldwide are missed by national TB programs annually, the level of under-reporting of diagnosed cases in high TB burden settings is largely unknown.OBJECTIVE: To quantify and describe under-reporting of sputum
smear-positive TB cases in Kenya.DESIGN: A national-level retrospective TB inventory study was conducted. All sputum smear-positive TB cases diagnosed by public or private laboratories during 1 April-30 June 2013 were extracted from laboratory registers in 73 randomly sampled subcounties
and matched to TB cases in the national TB surveillance system (TIBU). Bivariate and multivariate analyses were conducted.RESULTS: In the subcounties sampled, 715 of 3409 smear-positive TB cases in laboratory registers were not found in TIBU. The estimated level of under-reporting of smear-positive
TB cases in Kenya was 20.7% (95%CI 18.4-23.0). Under-reporting was greatest in subcounties with a high TB burden. Unreported cases were more likely to be patients aged 55 years, have scanty smear results, and be diagnosed at large facilities, private facilities, and facilities in
high TB burden regions.CONCLUSION: In Kenya, one fifth of smear-positive TB cases diagnosed during the study period went unreported, suggesting that the true TB burden is higher than reported. TB surveillance in Kenya should be strengthened to ensure all diagnosed TB cases are reported.