Statin Use Is Associated With a Lower Risk of TB [TBN 099]

A nationwide, population-based retrospective cohort study evaluated whether statin use was associated with a lower risk of incident tuberculosis (TB) disease. The study used Taiwan’s National Health Insurance Research Database from January 1, 2000, through December 31, 2013, which covers more than 99% of the Taiwanese population.

Adults aged 20 years or older with cumulative statin prescriptions for at least 30 days were included as statin users. Statins assessed included simvastatin, lovastatin, pravastatin, fluvastatin, atorvastatin, cerivastatin, rosuvastatin, and pitavastatin. Patients with TB before cohort entry, missing data, or no eligible matched control were excluded. Each new statin user was matched by age and sex to a nonuser using incidence-density sampling and the same index date. Statin exposure was quantified using cumulative defined daily doses (cDDDs), categorized as less than 180, 180 to 365, or more than 365 cDDDs. Incident TB required an ICD-9-CM code of 010 to 018 plus prescriptions for at least two anti-TB drugs for at least 4 weeks within 180 days of diagnosis. Participants were followed until TB diagnosis, death, withdrawal from insurance, or December 31, 2013. Analyses adjusted for age, sex, comorbidities, urbanization, and annual outpatient visits. This observational cohort provides moderate-level evidence for association, but not proof of causality.

The final analysis included 102,424 statin users and 202,718 nonusers, contributing 571,568 and 1,027,385 person-years of observation, respectively. Statin users had substantially more cardiometabolic and chronic diseases than nonusers, including diabetes (35.0% versus 7.1%) and coronary heart disease (18.3% versus 4.6%). After adjustment, statin use was associated with a 47% lower hazard of incident TB (adjusted hazard ratio [HR], 0.53; 95% CI, 0.47 to 0.61). The association showed a dose-response pattern: fewer than 180 cDDDs were not associated with reduced risk (HR, 1.06; 95% CI, 0.91 to 1.24), whereas 180 to 365 cDDDs were associated with lower risk (HR, 0.57; 95% CI, 0.45 to 0.72), and more than 365 cDDDs with the lowest risk (HR, 0.27; 95% CI, 0.22 to 0.33). A second exposure categorization reported in the supplied text produced similar estimates, including HRs of 0.65 for the intermediate category and 0.29 for the highest category. Independent predictors of higher TB risk included age 65 years or older (HR, 1.60; 95% CI, 1.42 to 1.80), male sex (HR, 3.68; 95% CI, 3.24 to 4.18), diabetes (HR, 1.22; 95% CI, 1.06 to 1.40), heart failure (HR, 1.51; 95% CI, 1.08 to 2.11), COPD (HR, 1.72; 95% CI, 1.42 to 2.10), asthma (HR, 1.51; 95% CI, 1.17 to 1.94), and systemic glucocorticoid use (HR, 1.47; 95% CI, 1.26 to 1.72).

In conclusion, statin use was associated with a substantially lower incidence of TB in Taiwan, particularly at higher cumulative exposure. Because the study was observational and based on administrative claims, residual confounding, exposure misclassification, healthy-user bias, and differences in underlying health status may remain. Generalizability outside Taiwan or to populations with different TB epidemiology is uncertain. Randomized or prospective studies would be needed before statins could be considered for TB prevention. 

Source: Su VY, Su WJ, Yen YF, Pan SW, Chuang PH, Feng JY, Chou KT, Yang KY, Lee YC, Chen TJ. Statin Use Is Associated With a Lower Risk of TB. Chest. 2017 Sep;152(3):598-606.