Diabetes mellitus and prediabetes among patients with tuberculosis in a single north Indian tertiary care centre.

Background: Prevalence of diabetes mellitus (DM), though believed to be high among patients with tuberculosis (TB), remains unclear for the want of systematic studies and unequivocal methods of diagnosing DM. This study was done to determine the prevalence of prediabetes and DM in adult patients with TB.

Methods: This prospective study of one year's duration, carried out at a tertiary care centre included 313 consecutive adult patients diagnosed (either microbiologically, histologically or based on clinical presentation) with pulmonary or extrapulmonary TB. Those without a history of pre-existing DM were subjected to oral glucose tolerance test (OGTT) with 75 g glucose.

Results: In this cohort 85 (27%) patients had pre-existing DM. The remaining 228 patients not diagnosed earlier with DM underwent a 75 g OGTT, of which 63 (28%) were found to have newly detected prediabetes (impaired fasting glucose [IFG] and impaired glucose tolerance [IGT] alone in 36 and 10 patients respectively and both IFG and IGT in a further 17) and DM was diagnosed in 9 (4%) patients (fasting blood glucose [FBG] ˜ 126 mg/dl in 1 and both FBG ˜ 126 mg/dl and 2-h plasma blood glucose [PLBG] ˜ 200 mg/dl in 8 patients). The total prevalence of (newly diagnosed) DM and prediabetes, therefore, was 32% (72 patients); the overall prevalence of DM was 30% (94 patients).

Conclusion: This study found high prevalence of prediabetes and diabetes among patients with TB. This underscores the need for a bidirectional screening strategy to improve diagnosis and outcome of both TB and DM.