Estimated glomerular filtration rate and the risk of stroke in individuals with diabetes mellitus and atrial fibrillation insight from a large contemporary population study

Background: Diabetes mellitus (DM) is associated with increased risk of embolic complications in non-valvular atrial fibrillation (NVAF). Impaired renal function (IRF) increases the risk of stroke as well, but this finding is not consistent among all studies. Our aim was to assess the incidence rates and risk of ischemic stroke and mortality by baseline Estimated Glomerular Filtration Rate (eGFR) levels Among individuals with AF and DM. Methods: A prospective, historical cohort study using the Clalit Health Services electronic medical records database. Among patients with AF and DM, we compared three groups according to eGFR levels: eGFR ≥ 60, between 30 and 60, and ≤ 30 (mL/min/1.73m²). Results: A total of 17,567 cases were included in the final analysis; of them, 11,013 (62.7%) had eGFR ≥ 60, 4930 (28%) had eGFR between 30 and 60, and 1624 (9.24%) with eGFR ≤ 30. The incidence of stroke per 100 person-years in the three study groups was: 1.88, 2.69, and 3.34, respectively (p < 0.001). IRF was associated with increased risk of stroke in univariate analysis, but not after multivariate adjustment (Adjusted Hazard Ratio (AHR) 0.96 {95%CI; 0.74–1.25} for eGFR 30–60 and 0.96 {95%CI; 0.60–1.55} for eGFR ≤ 30). Mortality per 100 person-years was 10.78, 21.49, and 41.55, respectively (p < 0.001). IRF was associated with increased mortality risk in univariate analysis, as well as in multivariate analysis (AHR 1.08 {95%CI; 0.98–1.18} for eGFR 30–60, and 1.59 {95%CI; 1.37–1.85} for eGFR ≤ 30. Conclusion: In patients with NVAF and DM, IRF was not associated with an increased risk of stroke, but severe IRF (eGFR ≤ 30) was associated with increased mortality risk.