Validation of Epidemiological Methods for Studying the Infection Risk in Rheumatoid Arthritis with Methotrexate Combined Biologicals using Propensity Scores

Probability Weighting Estimator（IPW）and Augmented Inverse Probability Weighting Estimator（AIPW） analyses. Results ：The Odds Ratios（OR）estimated by each method using the time axis of the elapsed time, the prescription number, and the administration time were 1.48（95％CI 0.71-3.11), 1.60（95％CI 0.72-3.55), and 1.04（95％CI 0.58-1.86), respectively. We performed PS weighting, of each Average Treatment Effect obtained from IPW, and the AIPW were estimated to be 0.31％（95％CI −0.91-1.53）and 0.29％（95％CI −0.91-1.49), respectively, and the average treatment effect on the treated was estimated to be 0.10％ （95％CI −1.11-1.32). We support the findings of a previous study which showed that the combination of biologicals was not statistically associated with increased infection risk. Conclusion ：This study suggests that estimators from different perspectives might be obtained by using some epidemiological methods. Therefore, our results could contribute to the establishment of an improved methodology.