Immortal time in observational studies can bias the results in favour of the treatment group, but it is not difficult to identify and avoid

Use of interrupted time series methods in drug utilization research has increased, particularly in recent years. Despite methodological recommendations, there is large variation in reporting of analytic methods. Developing methodological and reporting standards for interrupted time series analysis is important to improve its application in drug utilization research, and we provide recommendations for consideration.

These agents may have dual cardiopulmonary protective properties, thereby substantially altering prognosis of patients with COPD. These findings need confirmation in randomized clinical trials.