Estimated glomerular filtration rate levels and risk of stroke in individuals with diabetes mellitus and atrial fibrillation

Background: Diabetes mellitus(DM) is associated with increased risk of embolic complications in non-valvular atrial fibrillation(NVAF). Chronic kidney disease(CKD) has been shown in some studies to increase the risk of stroke. This finding is not consistent among all studies.

Aim: 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(CHS) electronic medical records database. The study population included all CHS members ≥21 years old, with a first diagnosis of NVAF between January 2010 to December 2016. Among those patients identified as diabetics, we compared three groups of patients according to eGFR levels at the time of AF diagnosis: eGFR>60, between 30-60 and≤30.

Results: A total of 17,567 cases were included in the final analysis, of them, 11013(62.7%) had GFR≥ 60, 4930(28%) with GFR between 30-60 and 1624(9.24%) with GFR≤30. The median age was 75 years with a majority of females in all groups. The incidence of stroke per 100 person-years in the three study groups was: 1.88, 2.69 and 3.34 respectively. Impaired renal function was associated with increased risk of stroke in univariate analysis, but not found in the adjusted model. (Adjusted Hazard Ratio (AHR) = 1.04{95% 0.89-1.23} GFR 30-60 and 1.16{95% CI 0.88-1.51} for GFR≤30) compared to GFR>60. The incidence of mortality per 100 person-years was 10.78 in patients with GFR≥ 60, 21.49 in GFR 30-60 and 41.55 in those with GFR≤30. In both univariate and multivariate analyses, decreased levels of GFR were associated with increased mortality risk compared to subjects with normal renal function(AHR 1.22{95%CI 1.14-1.27} and AHR 2.09{95%CI 1.95-2.24} for GFR between 30-60 and for GFR≤30, respectively).

Conclusion: Impaired renal function was not found to be associated with increased risk of stroke Among individuals with AF and DM. Lower GFR levels were associated with an increased mortality risk.