Reduced kidney function and anemia as risk factors for new onset AF

Background: Each of chronic kidney disease (CKD) and anemia is a potential independent risk factor for cardiovascular disease (CVD); however, reduced kidney function, anemia, and its relationship have not been fully evaluated for the incidence of atrial fibrillation (AF).

Objective: We sought to evaluate the impact of kidney function, hemoglobin and their combination on new onset AF in population-based cohort study.

Methods: We conducted a 15-year prospective cohort study of 194,333 persons aged 40-79 years who participated in annual health checkups in 1993 to 2008. Estimated glomerular filtration rate (eGFR) was classified as eGFR ≥90 ml/min per 1.73 m2 (normal eGFR group), 60 ≤ eGFR <90 mL/min per 1.73 m2 (mild CKD group), and eGFR <60 mL/min per 1.73 m2 (CKD group), The hemoglobin (Hb) was classified as normal Hb group (15 g/dl ≤ Hb < 18 g/dl in male and 13 g/dl ≤ Hb < 16 g/d in female); borderline Hb group (13 g/d ≤ Hb < 15 g/d in male and 11g/d ≤ Hb < 13 g/d in female) and anemia group (Hb < 13 g/dl in male and for Hb < 11 in female). Kaplan-Meier survival analysis was used to compare free from new onset of AF between groups classified by level of eGFR grade, hemoglobin grade, and their interaction. The Cox-proportional hazard model was used to estimate the hazard ratios (HRs) for new onset AF, after adjusting age, sex and other cardiovascular risk factors.

Results: During the mean follow up of 13.8 years, 1,237 new onset of AF (0.93%) were identified. Lower eGFR and lower hemoglobin grades were significantly associated with a higher prevalence of new onset AF. The multivariable HRs and 95% confidence intervals (CIs) of new onset AF was 1.37 (1.21 – 1.55) for mild CKD group, 2.55 (2.08 -3.12) for CKD group; and 1.50 (1.24 – 1.83) for anemia grade. Borderline hemoglobin level was not significantly associated with increased risk for new onset AF (HR = 1.07 CI: 0.91 – 1.25 P = 0.4284). In the model with interaction term between CKD and anemia, the risk was significantly higher (P = 0.0343 for the interaction) than that predicted by both factors independently.

Conclusion: Decreased kidney function and lower hemoglobin level are risk factors for new onset AF, especially when both are present.

Source: congress365.escardio.org