Diabetes mellitus among patients attending TB clinics in Dar es Salaam: a descriptive cross-sectional study

A bi-directional interaction between diabetes mellitus and tuberculosis is well established and has been likened to that between HIV and TB. Whereas HIV screening is standard of care test in sub Saharan Africa TB programs, the same is not true for diabetes mellitus (DM). Sub Saharan Africa, a region with high TB infection rates, is going through an epidemiological transition with rapidly rising prevalence of diabetes. We aimed at characterizing TB patients with DM in order to identify factors associated with TB-DM dual disease among patients attending TB clinics in Dar es Salaam.

A cross-sectional study was conducted between September 2016 and January 2017 among patients attending TB clinics in Dar es Salaam. We collected socio-demographic characteristics, anthropometric measurements and screened for diabetes by measuring fasting blood glucose that was followed by a 2 h postprandial glucose for participants with impaired fasting blood glucose. We examined for socio-demographic and clinical factors associated with diabetes using logistic regression analysis.

Of the 660 enrolled participants with TB, 25 (3.8%) were on treatment for diabetes while 39 (6.1%) and 147 (23%) of the remaining 635 participants were ultimately diagnosed with DM and impaired fasting blood glucose respectively. The overall prevalence of DM was 9.7% (64/660). Independent risk factors for diabetes included: age > 44 years {OR 4.52, 95% CI: [1.28-15.89]}; family history of diabetes {OR 3.42, 95% [CI 1.88-6.21]}. HIV sero-positive TB patients were less likely to have DM compared to those who were HIV sero-negative {OR 0.35, 95% CI [0.17-0.73]}.

Screening for diabetes should be advocated for TB patients aged above 44 years and/or with a family history of diabetes. HIV sero-negative TB patients were more likely to have DM compared to those who were HIV sero-positive. Further studies are needed to confirm this observation and the underlying factors.