Limitations
The number of patients in this cohort was small, and the single-centre, retrospective, observational design of our study makes the establishment of causal relationships difficult. Further, our AR cohort was derived from a single tertiary referral centre in Japan and was thus subject to selection bias by including a highly selected population of patients with AR. We did not assess outcomes in this study. Therefore, a larger scale study with a larger number of patients and a longer period of follow-up and assessment of prognosis is needed to confirm our findings.