Incident atrial fibrillation and the risk of congestive heart failure, myocardial infarction, end-stage kidney disease, and mortality among patients with a decreased estimated GFR

Background — The association of atrial fibrillation (AF), estimated glomerular filtration rate (eGFR), and adverse events.

Study Design — Population-based retrospective cohort study from Ontario, Canada.

Setting and Participants — 1,422,978 adult residents with eGFRs < 90mL/min/1.73m2 from April 1, 2006, through March 31, 2015.

Factor — A diagnosis of AF at hospitalization.

Outcomes — Congestive heart failure (CHF), myocardial infarction (MI), end-stage kidney disease, all-cause mortality.

Results — All adverse events were more frequent in individuals with AF (93,414 propensity score matched) compared to no AF, and this difference was more pronounced within the first 6 months of the index date (CHF: 3.04% [AF] vs 0.28% [no AF], subdistribution HR [sHR] of 11.57 [95% CI, 10.26-13.05]; MI: 0.97% [AF] vs 0.21% [no AF], sHR of 4.76 [95% CI, 4.17-5.43]; end-stage kidney disease: 0.16% [AF] vs 0.03% [no AF], sHR of 5.84 [95% CI, 3.82-8.93]; and all-cause mortality: 6.11% [AF] vs 2.50% [no AF], HR of 2.62 [95% CI, 2.50-2.76]) than in the period more than 6 months after the index date (CHF: 6.87% [AF] vs 2.87% [no AF], sHR of 2.64 [95% CI, 2.55-2.74]; MI: 2.21% [AF] vs 1.81% [no AF], sHR of 1.24 [95% CI, 1.18-1.30]; end-stage kidney disease: 0.52% [AF] vs 0.32% [no AF], sHR of 1.75 [95% CI, 1.57-1.95]; and all-cause mortality: 15.55% [AF] vs 15.10% [no AF], HR of 1.07 [95% CI, 1.04-1.10]). The results accounted for the competing risk for mortality. eGFR level modified the effect of AF on CHF (P for interaction < 0.05).

Limitations — Observational study design does not permit determination of causality; only a single outpatient eGFR measure was used; medication data were not included.

Conclusions — Incident AF is associated with a high risk for adverse outcomes in patients with eGFRs < 90mL/min/1.73m². Because the risk is exceedingly high within the first 6 months after AF diagnosis, therapeutic interventions and monitoring may improve outcomes.