Increased risk of ankylosing spondylitis after Mycoplasma pneumonia: A Nationwide population-based study

This study aimed to investigate the relationship between Mycoplasma pneumonia (MP) infection and new development of ankylosing spondylitis (AS). Using data from the Taiwan National Health Insurance Research Database, we included a total of 116,084 patients with newly diagnosed MP between 2000 and 2012. The control cohort consisted of patients who did not have MP, matched 1:4 by age, sex, and index year. The follow-up period was defined as the time from the initial diagnosis of MP to the date of diagnosis of AS, censoring, or 31 December 2013. Cox proportional hazards regression analysis was used to analyze the risk of autoimmune diseases by sex, age, and comorbidities, with hazard ratios (HRs) and 95% confidence intervals (CIs). The eligible study participants included 116,084 patients in the MP group and 464,336 patients in the comparison group. The incidence rates of AS in the MP group and comparison groups were 1.49 and 0.74 per 1,000,000-person years, respectively. The adjusted HR of AS for the MP group was 2.45 (95% CI = 1.02−5.90) compared to the control group after adjustment for age, sex, and all covariates. MP remained an independent risk factor for developing AS in terms of sex, age, and comorbidities.