Estimated glomerular filtration rate and risk of poor outcomes after stroke

The relationship of the estimated glomerular filtration rate (eGFR) with complications after stroke has not been fully characterized for the entire clinical spectrum of eGFR and for the fluctuation in eGFR during hospital stay.

Data from the Norfolk and Norwich Stroke Registry recorded between January 2003 and April 2015 were analysed. eGFR was categorized into six clinically relevant categories as per the Kidney Disease Improving Global Outcomes guidelines. The change in eGFR during acute admission was categorized into the following: within 5% change (reference), 5%-20% decline, >20% decline, 5%-20% increase and >20% increase. All-cause mortality, recurrent stroke, incident myocardial infarction, prolonged hospital stay and stroke disability at discharge were outcomes of interest.

In all, 10 329 stroke patients (mean age 77.8 years) were followed for a mean of 2.9 years (30 126 person-years). Multivariable adjusted hazard ratios (95% confidence interval) for all-cause mortality were 0.91 (0.80-1.04), 0.96 (0.83-1.11), 1.23 (1.06-1.43), 1.54 (1.31-1.82) and 2.38 (1.91-2.97) for eGFR levels 60-89, 45-59, 30-44, 15-29 and <15 respectively, compared to eGFR ≥ 90 ml/min/1.73 m² . The hazard ratios (95% confidence interval) for eGFR change were 1.56 (1.36-1.79), 1.17 (1.05-1.30), 1.47 (1.32-1.62) and 1.71 (1.55-1.88) for >20% decline, 5%-20% decline, 5%-20% increase and >20% increase, respectively, compared to change within 5%. Results were similar for other outcomes except recurrent stroke.

Stroke patients with eGFR < 45 ml/min/1.73 m² at hospital admission and >5% decline or increase in eGFR during hospital stay were at substantially higher risk of poor outcomes, particularly all-cause mortality, myocardial infarction, prolonged hospital stay and disability at discharge.