Temporal trends in multimorbidity patterns in patients with atrial fibrillation – a nationwide cohort study

Background The prevalence of atrial fibrillation (AF) and multimorbidity are increasing with population aging. However, there is limited reliable data on temporal trends in multimorbidity among patients with AF. Purpose We aimed to assess the prevalence and temporal trends in multimorbidity in patients with AF. Methods We conducted a nationwide retrospective cohort study using the Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) cohort, including all patients with incident AF between 2009 and 2018. Data on comorbidities were obtained from national healthcare, reimbursement, and prescription registers. Previously established diagnosis clusters covering the entire spectrum of diagnose codes were applied to characterize multimorbidity burden. A five-year look-back period was applied to define the presence of diagnosis codes in the registers. We assessed temporal trends in the prevalence of common comorbidities and in the number of distinct diagnosis clusters at the time of new-onset AF. Results A total of 196,536 patients with new-onset AF were identified between 2009 and 2018, of whom 98,101 (49.9%) were women, and their mean age was 72.9 (SD 13.1) years. At the time of AF diagnosis, the patients had a mean of 4.1 (SD 2.5) comorbidity clusters, with women exhibiting more clusters than men (4.2 vs 3.9, p < 0.001). 85% of individuals with new onset AF had diagnoses from ≥2 comorbidity clusters, and the prevalence increased over time (Figure). Multimorbidity was more common in women and older individuals. Hypertensive diseases, obesity and other metabolic diseases, diabetes, and other cardiovascular diseases were most prevalent. The prevalence of ischaemic heart disease and other diseases of the heart and pulmonary circulation declined. Conclusions Multimorbidity is highly prevalent and increasing among patients with AF.