Seasonal Variation of Atrial Fibrillation Admission and Quality of Care in the United States.

Background Currently, little is known regarding seasonal variation for atrial fibrillation (AF) in the United States and whether quality of care for AF varies between seasons. Methods and Results The GWTG-AFib (Get With The Guidelines-AFib) registry was initiated by the American Heart Association to enhance national guideline adherence for treatment and management of AF. Our analyses included 61 291 patients who were admitted at 141 participating hospitals from 2014 to 2018 across the United States. Outcomes included numbers of AF admissions and quality-of-care measures (defect-free care, defined as a patient's receiving all eligible measures). For quality-of-care measures, generalized estimating equations accounting for within-site correlations were used to estimate odds ratios (ORs) with 95% CIs, adjusting patient and hospital characteristics. The proportion of AF admissions for each season was similar, with the highest percentage of AF admissions being observed in the fall (spring 25%, summer 25%, fall 27%, and winter 24%). Overall, AF admissions across seasons were similar, with no seasonal variation observed. No seasonal variation was observed for incident AF. There were no seasonal differences in care quality (multivariable adjusted ORs and 95% CIs were 0.93 (0.87-1.00) for winter, 1.09 (1.01-1.18) for summer, and 1.08 (0.97-1.20) for fall, compared with spring). Conclusions In a nationwide quality improvement registry, no seasonal variation was observed in hospital admissions for AF or quality of care for AF.