Low Kidney Function and Proteinuria Separately Linked to Adverse Outcomes After Stroke

Full access

In patients with ischemic stroke, the decreased estimated glomerular filtration rate (eGFR) and proteinuria are separately and independently associated with stroke recurrence and death, reports a study in Stroke.

The researchers analyzed prospective follow-up data on 12,576 patients with ischemic stroke (41.3% women; mean age, 73 years). Data were drawn from the Japanese Fukuoka Stroke Registry from 2007 to 2019. Patients were classified into groups based on eGFR values of ≥60, 45–59, or <45 mL/min/1.73 m2, and with proteinuria classified as −, ±/1+, or 2+ or greater.

The measurements of kidney function and kidney damage were evaluated as predictors of recurrent stroke and all-cause mortality. At a median follow-up of 4.3 years, recurrent stroke incidence was 48.0 per 1000 patient-years, and mortality was 67.3 per 1000 patient-years. Chronic kidney disease (CKD), defined as decreased eGFR or the presence of proteinuria, was associated with increased risks of recurrent stroke and death, independent of traditional cardiovascular risk factors.

For recurrent stroke, adjusted hazard ratios (HRs) were 1.22 for patients with an eGFR <45 mL/min/1.73 m2 (compared with ≥60 mL/min/1.73 m2) and 1.25 for those with proteinuria of 2+ or greater (compared with absent proteinuria). For all-cause mortality, HRs were 1.45 and 1.62, respectively.

The association of proteinuria with recurrent stroke tended to decrease on analysis considering competing causes of death. The mortality effect of proteinuria was stronger for patients younger than age 75 compared with older patients and for those with non-cardioembolic versus cardioembolic stroke.

Decreasing eGFR and increasing proteinuria are “mutually independent risk factors” for long-term stroke recurrence and death, the findings suggest. The associations are heterogeneous for proteinuria, indicating possible differences in the pathophysiologic mechanisms of the two risks. “Further studies are needed to determine whether interventions targeting CKD can offer additional benefits to poststroke outcomes following ischemic stroke,” the researchers write [Ueki K, et al. Decreased estimated glomerular filtration rate and proteinuria and long-term outcomes after ischemic stroke: A longitudinal observational cohort study. Stroke 2023; 54:1268–1277; doi: 10.1161/STROKEAHA.122.040958].