I am working on a comparative effectiveness study where we estimated the propensity of treatment between two groups and are exploring matching on the propensity score. The study period is long, encompassing about 7 years of data, and exposed and unexposed patients are selected across the entire period at different points. The propensity score itself is estimated using a high dimensional propensity score estimation method that includes the year of the index date and several other potential confounders. In general, the propensity score balances confounding between the two treatment groups.
In my experience, matching exposed and unexposed patients (using the date of exposure as the index date) in this context is a matched cohort study and would be analyzed as usual like a cohort study. In the past, I would also ensure that exposed and unexposed patients came from a similar point in time in case there were changes in the standard of care or treatment practices over the study period that would confound the treatment effect.
My questions are: can the data be analyzed after matching on the propensity score without needing to further ensure the patients come from a similar point in time? Would this have an impact on the treatment effect estimate or introduce a bias in any way and if so, how should I address it?
Thank you for your time!