National population-based tuberculosis prevalence survey in Ghana, 2013

BACKGROUND: The prevalence of tuberculosis (TB) disease is one of the three main indicators used to assess the epidemiological burden of TB and the impact change of TB control; the other two are incidence and mortality.

OBJECTIVE: To estimate the prevalence of TB disease among adults in Ghana.

METHODS: A nationally representative cross-sectional survey was conducted. Participants were screened for TB using interview and chest X-ray (CXR). For those participants with cough ≥2 weeks and/or abnormal CXR, spot and morning sputum specimens were collected and examined by smear microscopy and culture.

RESULTS: The study revealed that the prevalence of smear-positive TB among adults (age ≥15 years) was 111 (95%CI 76–145) and that of bacteriologically confirmed TB was 356 (95%CI 288–425) per 100 000 population. Males and older people had a higher prevalence than their counterparts. The majority of TB cases were smear-negative and had an abnormal CXR without reported chronic cough.

CONCLUSION: The survey revealed much higher TB disease burden than previously estimated. This implies that the programme needs more effort and resources to find undiagnosed and unreported cases. The higher proportion of smear-negative and asymptomatic TB cases suggests the need to revise the existing screening and diagnostic algorithms.