Glucocorticoid use, other associated factors, and the risk of tuberculosis

Objective. To evaluate the association of glucocorticoids and other purported risk factors with the development of tuberculosis. Methods. We conducted a case-control study of tuberculosis cases identified during 1990-2001 using the General Practice Research Database in the United Kingdom. Cases were patients with a first time diagnosis of tuberculosis accompanied by at least 6 months of treatment with at least 3 different tuberculosis medications. Up to 4 controls were matched to each case on age, sex, the practice attended by the case, index date, and amount of prior computerized records. Results. The study encompassed 497 new cases of tuberculosis and 1,966 controls derived from 16,629,041 person-years at risk (n = 2,757,084 persons). The adjusted odds ratio (OR) of tuberculosis for current use of a glucocorticoid compared with no use was 4.9 (95% confidence interval [95% CI] 2.9-8.3). The adjusted ORs for use of < 15 mg and >= 15 mg of prednisone or its equivalent daily dose were 2.8 (95% CI 1.0-7.9) and 7.7 (95% CI 2.8-21.4), respectively. Adjusted ORs of tuberculosis were 2.8 for patients with a body mass index (BMI) < 20 compared with normal BMI; 1.6 for current smokers compared with nonsmokers; and 3.8, 3.2, 2.0, and 1.4 for those with history of diabetes, emphysema, bronchitis, and asthma, respectively, compared with those without such history (all P values < 0.05). Conclusion. These results indicate that patients treated with glucocorticoids have an increased risk of developing tuberculosis, independent of other risk factors. Low adiposity, diabetes, current smoking, and obstructive pulmonary disorders are also important independent risk factors for tuberculosis.