Association of glomerular hyperfiltration with mortality in stroke: an analysis using pooled individual patient data.

INTRODUCTION: Glomerular hyperfiltration has previously been associated with cardiovascular events and mortality but has scarcely been investigated in patients with stroke. PATIENTS AND METHODS: We used pooled data from an individual patient data meta-analysis of prospective, cohort studies of stroke or TIA populations. For this analysis, we included participants from study sites that collected estimated glomerular filtration rate (eGFR) at stroke presentation. Using Cox proportional hazards regression, we investigated the risk of death, any stroke and vascular death according to glomerular hyperfiltration, defined as having an eGFR greater than the age- and sex-adjusted 95th percentile. We also investigated these outcomes according to eGFR as a continuous variable, modelled using fractional polynomials. RESULTS: A total of 11,175 patients (mean age 70.7 years, 42% female) were included in the analysis, 554 (4.9%) with hyperfiltration. Compared to the normofiltration group (absence of hyperfiltration and eGFR ≥ 60 mL/min/1.73 m2), the hyperfiltration group had a higher rate of all-cause death, 147 per 1000 person-years (95% CI, 119-180) vs 61 (95% CI, 57-66). Compared to normofiltration, hyperfiltration was independently associated with the risk of death from any cause (adjusted hazard ratio [HR] 1.76; 95% CI, 1.46-2.11; P < .001) and the risk of vascular death (adjusted HR 1.68; 95% CI, 1.29-2.17; P < .001). There were non-linear associations of eGFR with risk of death and vascular death, with increasing risk at both low and high eGFR (Pnon-linearity < .001 for both). DISCUSSION AND CONCLUSION: Glomerular hyperfiltration was associated with a 76% increased risk of death and a 68% increased risk of vascular death in multivariable models adjusted for age, sex and comorbidities. Glomerular hyperfiltration may be associated with adverse health outcomes, specifically in patients with ischaemic stroke. Further research is needed to confirm these findings.