Health Care Visits as a Risk Factor for Tuberculosis in Taiwan: A Population-Based Case–Control Study

Objectives. To assess whether health care visits of nontuberculous patients are a risk factor for contracting tuberculosis.Methods. We conducted a case–control study nested within the cohort of 1 million individuals from the health insurance database in Taiwan between 2003 and 2010. We identified incident cases of tuberculosis through International Classification of Diseases, Ninth Revision (ICD-9) codes and prescription of antituberculosis drugs. We identified 4202 case participants and 16 808 control participants matched by age, gender, and date of diagnosis to estimate the association between frequency of health care visits and incidence of tuberculosis.Results. Frequency of health care visits was associated with increased risk of tuberculosis in a dose-dependent manner after adjustment for other medical comorbidities (P for trend < .001). Compared with individuals with fewer than 5 visits per year, those with more than 30 had a 77% increase in tuberculosis risk (adjusted odds ratio = 1.77; 95% confide...