The impact of diabetes on tuberculosis treatment outcomes: evidence based on a cumulative meta-analysis

Diabetes mellitus (DM) is a known risk factor for tuberculosis (TB). It is also associated with worse tuberculosis treatment outcomes. This study aimed to perform a systematic review and meta-analysis to quantitatively summarize evidence for the impact of diabetes on tuberculosis outcomes. We searched PubMed, Cochrane, and Web of Science from January 1980 to July 2015. The combinations of key words used were (((((“Tuberculosis”[Mesh]) OR (Tuberculosis OR pulmonary tuberculosis OR TB))) AND ((“Diabetes Mellitus”[Mesh]) OR (Diabetes Mellitus OR Diabetes OR DM))) AND (Outcome OR sequelae OR treatment OR therapy OR culture conversion OR failure OR death OR relapse OR recurrence)). We reviewed the full text of 70 papers and included 54 studies of which 16 reported culture conversion at 2 to 3 months, 24 reported the combined outcome of failure and death, 34 reported death, 8 reported relapse, and 7 reported drug-resistant recurrent tuberculosis. Patients with diabetes have an odds ratio (OR) through this cumulative meta-analysis for the combined outcome of failure and death of 1.96 (95 % CI, 1.64 to 2.33). The OR of death during tuberculosis treatment among the 34 unadjusted studies is 1.83 (95 % CI, 1.61 to 2.07). Diabetes is also associated with an increased risk of relapse (OR, 1.97; 95 % CI, 1.42 to 2.74). The OR for studies assessing sputum culture conversion after 2 to 3 months of tuberculosis therapy is 1.71 (95 % CI, 1.50 to 1.94). Diabetes increases the risk of failure and death combined, death, and relapse among patients with tuberculosis. This study highlights a need for increased attention to treatment of tuberculosis in people with diabetes, which may include testing for suspected diabetes, improving glucose control, and increasing clinical and therapeutic monitoring.