Glycated hemoglobin screening identifies patients admitted for retreatment of tuberculosis at risk for diabetes in Tanzania.

Abstract

World Health Organization recommendations of bidirectional screening for tuberculosis (TB) and diabetes have been met with varying levels of uptake by national TB programs in resource-limited settings. Kibong'oto Infectious Diseases Hospital (KIDH) is a referral hospital for TB from northern Tanzania, and the national referral hospital for multidrug-resistant (MDR)-TB. Glycated hemoglobin (HgbA1c) testing was done on patients admitted to KIDH for newly diagnosed TB, retreatment TB, and MDR-TB, to determine the point prevalence of diabetes (HgbA1c ≥ 6.5%) and prediabetes (HgbA1c 5.7%-6.4%). Of 148 patients hospitalized at KIDH over a single week, 59 (38%) had no prior TB treatment, 22 (15%) were retreatment cases, and 69 (47%) had MDR-TB. Only 3 (2%) had a known history of diabetes. A total of 144 (97%) had successful screening, of which 110 (77%) had an HgbA1c ≤ 5.6%, 28 (19%) had ≥ 5.7 < 6.5, and 6 (4%) had ≥ 6.5. Comparing subjects with prediabetes or diabetes to those with normal A1c levels, retreatment patients were significantly more likely to have a A1c ≥ 5.7% (odds ratio: 3.2, 95% CI: 1.2-9.0; p = 0.02) compared to those without prior TB treatment. No retreatment case was a known diabetic, thus the number needed to screen to diagnose one new case of diabetes among retreatment cases was 11. Diabetes prevalence by HgbA1c was less common than expected, but higher HgA1c values were significantly more frequent among retreatment cases, allowing for a rational, resource-conscious screening approach.