The majority of cases of type 2 diabetes mellitus (DM) in patients with tuberculosis (TB) are diagnosed, but are poorly controlled in 4 TB-endemic countries, according to a study published in Clinical Infectious Diseases.1 Moreover, many people with comorbid TB and DM had significant cardiovascular disease risk and severe TB.

The increased prevalence of DM in low- and middle-income countries, which increases the risk for active TB 3-fold,2 has put TB control in jeopardy, notably in TB-endemic countries.3 As part of the TANDEM study, a consortium funded by the European Union, DM status and clinical correlates were assessed in patients with TB across settings in Indonesia, Peru, Romania, and South Africa.1

A total of 2185 patients with TB were enrolled in the study: Indonesia, n=748; Peru, n=600; Romania, n=506; and South Africa, n=331. Most patients were men (61.2%), the median age was 36.6 years, and 3.8% (n=82) of patients were HIV positive, the highest proportion from South Africa (9.7%). Of the 2185 patients, 57 were missing data on DM diagnostic testing.

A total of 267 (12.5%) patients had confirmed DM, one-third of whom were newly diagnosed. Age-standardized DM prevalence was highest in Indonesia (19.7%), similar in Peru and Romania (12.3% for both), and lowest in South Africa (10.9%). There were substantial between-country differences in median glycated hemoglobin (HbA1c) level and patients with TB and DM: 11.3% in Indonesia, 10.6% in Peru, 10.1% in South Africa, and 7.4% in Romania.

Compared with patients who did not have DM, patients with comorbid TB/DM were more frequently smear (72.7% vs 80.2%, P =.009) and culture positive (81.4% vs 91.5%, P <.001). Patients with comorbid TB/DM were older, had a higher body mass index (BMI) and lower waist-hip ratios, lower socioeconomic status, and were more likely to have a family history of diabetes (P <.001 for all). They were also more likely to have a more than 10% risk for a major cardiovascular event occurring within 10 years compared with those with solely TB (24.5% vs 5.5%).

While similar in age, compared with patients with previously diagnosed DM, those with a new DM diagnosis had a TB score of ≥3 on diagnosis (65.6% vs 77.4%; P <.001) suggesting greater TB disease severity. Unlike those with a previously diagnosed DM, newly diagnosed individuals had a lower BMI (P =.02), lower HbA1c (P =.05), and less were likely to have a family history of DM (P =.001). Moreover, they had ≤2 Charlson comorbidity index scores (2.4% vs 47%; P =.001), and fewer DM complications, including hypertension and macrovascular or microvascular disease (2.4% vs 43.2%; P =.001).

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Prevalence and characteristics of DM in patients with TB varied considerably between countries. “Many patients with combined TB and DM had significant cardiovascular disease risk and severe TB, underlining the need to improve strategies for better clinical management of combined TB and DM,” concluded the researchers.

References

  1. Ugarte-Gil C, Alisjahbana B, Ronacher K, et al; TANDEM Consortium. Diabetes mellitus among pulmonary tuberculosis patients from four TB-endemic countries: the TANDEM study [published online April 8, 2019]. Clin Infect Dis. doi:10.1093/cid/ciz284
  2. Huangfu P, Ugarte-Gil C, Golub J, Pearson F, Critchley J. The effects of diabetes on tuberculosis treatment outcomes: an updated systematic review and meta-analysis. J Epidemiol Community Health. 2016;70:A50-A51.
  3. World Health Organization. Global tuberculosis report 2018. https://www.who.int/tb/publications/global_report/en/. Updated February 28, 2019. Accessed April 28, 2019.