Pulmonary tuberculosis and diabetes. A retrospective study of 60 patients in Tunisia

BACKGROUND: Tuberculosis is a frequent infectious disease in Tunisia. The estimated case rate is 22.3 per 100,000 inhabitants. The risk of tuberculosis is 2 to 6 times greater in patients with diabetes. The purpose of this study was to analyze the particularities in the etiology, diagnosis and bacteriologic course of pulmonary tuberculosis in patients with diabetes and to evaluate the impact of tuberculosis on diabetes control. METHOD: This retrospective case-control study of 142 patients with confirmed pulmonary tuberculosis seen from 2000-2006 compared the 60 patients with diabetes with the 82 without diabetes. RESULTS: Diabetes was more frequent in older patients with tuberculosis and in women. 91.5% had type 2 diabetes. A history of contact with people with tuberculosis was significantly less frequent in the group with diabetes (13.3% vs 30.5%; p=0.01). Tuberculosis symptoms and their duration did not differ between the 2 groups. Basal lesions and cavitation occurred more frequently in the patients with diabetes, but this difference was not significant. The time for conversion to negative of sputum culture was longer in case patients (43+/-27 days) than in controls (28.2+/-20.5) (p=0.03). The proportion of patients with uncontrolled diabetes was elevated, and 50% required frequent insulin treatment. CONCLUSION: Tuberculosis is frequently associated with diabetes, usually due to reactivation of Mycobacterium tuberculosis. It is characterized by a longer time to culture conversion to negative and a risk of uncontrolled diabetes that requires frequent treatment adjustment and insulin use.