Prolonged diabetes duration tied to higher risk of TB in Koreans

Prolonged duration of diabetes may increase the risk of developing tuberculosis (TB) among the general population in Korea, according to a recent study.

Using data from the Korean National Health Insurance System database, the researchers conducted a population-based cohort study involving 4,423,177 Korean adults (mean age 46.5 years, 58.7 percent male) to evaluate the association between diabetes status and development of TB. Participants were categorized into five groups according to glycaemic status: normal glucose (FPG* <100 mg/dL; n=3,030,004), impaired fasting glucose ([IFG]; FPG 100–125 mg/dL; n=1,017,410), new-onset diabetes (FPG ≥126 mg/dL; n=135,448), and diabetes duration of <5 years (n=128,882) and ≥5 years (n=111,433). [JAMA Network Open 2021;doi:10.1001/jamanetworkopen.2021.26099]

At a median follow-up of 8.3 years, the researchers identified 26,458 individuals diagnosed with TB, and also found that individuals with diabetes had a higher risk of TB than those without diabetes (adjusted hazard ratio [adjHR], 1.48).

With regard to diabetes duration, an increased risk of TB incidence was observed among individuals with new-onset diabetes (adjHR, 1.32) and diabetes duration of <5 and ≥5 years (adjHRs, 1.45 and 1.57, respectively).

Moreover, a higher incidence of TB was prominent in men (adjHR, 1.84) and younger (aged <45 years; adjHR, 4.61) individuals with a longer diabetes duration of ≥5 years than those with normal glucose levels.

On the other hand, those with IFG, which was considered as individuals without diabetes, had no increased risk of TB (adjHR, 0.97).

Among participants with new-onset diabetes, those who had an FPG level of ≥202 mg/dL (highest decile) demonstrated a significantly higher risk of TB compared with those who had an FPG level of 126–128 mg/dL ([lowest decile]; adjHR, 1.79). “These findings suggest that for TB prevention, FPG control should be reinforced even in patients with new-onset diabetes,” said the researchers.

“[Previous studies have shown that] diabetes appears to be associated with increased risk of lower respiratory tract infection, including TB, and to have a profound adverse effect on TB treatment outcomes,” according to the researchers. [PLoS One 2017;doi:10.1371/journal.pone.0187967; BMC Med 2011;doi:10.1186/1741-7015-9-81] “[Overall,] these findings suggest that longer diabetes duration is associated with [the] development of TB, showing a dose-response association,” they concluded.

“[In addition,] TB incidence was more common among patients with new-onset diabetes and FPG level of ≥202 mg/dL [than 126–128 mg/dL],” they said.

“The findings of this study support the positive association between diabetes duration and TB risk … This association was robust in participants with longer diabetes duration, especially in men and younger participants,” noted the researchers.
 

*FPG: Fasting plasma glucose