To assess the yield of finding additional TB or diabetes mellitus (DM) cases through systematic screening and to determine the effectiveness of preventive TB therapy in people with DM.
We systematically reviewed studies that had screened for active TB or implemented preventive therapy for TB among people with DM, and those that screened for DM among patients with TB. We searched published literature through PubMed and EMBASE and included studies that reported the number of TB cases identified among people with DM; the number of DM cases identified among patients with TB, or the relative incidence of TB between people with DM who received a TB prophylaxis and those who did not. We assessed the yield of screening by estimating the prevalence of TB or DM in each study, the prevalence ratio and difference where comparison populations were available, and the number of persons to screen to detect an additional case of TB or DM.
Twelve studies on screening for TB in people with DM and 18 studies on screening for DM in patients with TB met our inclusion criteria. Screening for TB in persons with DM demonstrated that TB prevalence in this population is high, ranging from 1.7% to 36%, and increasing with rising TB prevalence in the underlying population as well as with DM severity. Screening patients with TB for DM also yielded high prevalences of DM ranging from 1.9% to 35%. Two studies examining the role of TB preventive therapy in people with DM did not provide sufficient details for clear evidence of the effectiveness.
Active screening leads to the detection of more TB and DM with varying yield. This review highlights the need for further research in screening and preventive therapy.