Risk of ankylosing spondylitis following human papillomavirus infection

Objective: To assess the incidence rate and risk of ankylosing spondylitis (AS) in patients with previous human papillomavirus (HPV) infection compared with those without HPV infection. Methods: All patients with HPV infection (n = 66,314) in the NHIRD (2003–2013) were individually matched with up to four control subjects without HPV infection by age and sex (n = 265,256). All of the patients were tracked until an AS event was noted. Chi-square test was used to analyze the distribution of sociodemographic characteristics in the HPV cohort and non-HPV cohort. Cox proportional hazards regression was used to calculate the HRs for the development of AS, adjusting for age, sex, urbanization, length of hospital stay, medications, and comorbidities adjustment. The Kaplan-Meier method was used to plot the cumulative incidence curves. Results: The HPV cohort had a 1.329 (95% C.I. = 1.138–1.552) times higher risk of AS than that of the non-HPV cohort after adjusting for sex, age, urbanization, length of hospital stay, comorbidities, and medications. Additionally, we applied propensity score weighting to reconfirm the accuracy of our analysis, and the results showed a 1.348 (95% C.I. = 1.153–1.575) times greater risk of AS in the HPV cohort compared with the non-HPV cohort. The cumulative incidence curves plotted by the Kaplan-Meier method revealed that after 120 follow-up months, the HPV cohort displayed a higher cumulative incidence of AS than that of the non-HPV cohort. (Log-rank test p < 0.0001). Conclusions: Patients with HPV infection had a higher risk of developing AS compared with non-HPV patients.