Sex-differences in self-reported cardiorespiratory fitness, symptom severity, and quality of life in patients with atrial fibrillation

Patients with atrial fibrillation (AF) often report low cardiorespiratory fitness (CRF), a strong predictor of all-cause mortality, troubling symptoms, and poor quality (QoL). Scarce literature suggests there are sex-differences in cardiovascular outcomes between females and males with AF. Despite sex-based analysis being encouraged in research practices, it is often overlooked, and this research gap in those with AF merits examination.

We aimed to assess the sex-differences in CRF, symptom severity, and disease-specific QoL in patients with AF.

This is an observational study in patients with AF within Canada. Estimated CRF (i.e., peak oxygen uptake [V̇O2peak], and metabolic equivalents [METs]) was measured using the Duke Activity Status Index (DASI). Symptom severity including AF frequency, AF duration, symptom severity, and total AF burden was assessed using the Atrial Fibrillation Severity Scale (AFSS). Disease-specific QoL was examined using the Atrial Fibrillation Effect on Quality of Life (AFEQT) which includes domains of symptoms, physical functioning, treatment concerns, and treatment satisfaction. Mann-Whitney U tests were performed to determine sex-differences on the above-mentioned variables. A P value of < 0.05 was considered significant. Data are presented as medians and 95% confidence intervals.

This study included 210 (33%) females (66.0 [63.5-68.0] years) and 409 (66%) males (66.0 [64.0-67.0] years). Females reported lower levels of CRF as assessed by V̇O2peak (25.5 [23.3-27.2] vs. 30.0 [27.6-30.2] mL/kg/min, P < 0.001) and METs (7.2 [6.6-7.7] vs. 8.5 [7.9- 8.6], P < 0.001) compared to males. Females showed worse symptom severity (5.5 [5.2-6.0] vs. 5.0 [4.5-5.0] points, P < 0.001) and were more bothered by AF symptoms (7.0 [5.0-8.0] vs. 5.0 [4.0-5.0] points, P < 0.001) than males. Females also demonstrated poorer QoL than males (AFEQT total score: 80.6 [77.8-83.3] vs. 83.3 [80.6-86.1] points, P = 0.04).

Our findings show that females with AF reported clinically and statistically poorer CRF, and worse symptom severity and QoL when compared to males with AF. Our findings emphasize the need for sex-specific strategies to improve AF management, particularly in females.