Prevalence and Significance of Unrecognized Renal Dysfunction in Patients with Stroke

Background Unrecognized renal dysfunction, defined as an estimated glomerular filtration rate <60 mL/min/1.73 m² in the presence of normal serum creatinine levels, is a common comorbidity among patients with various cardiovascular conditions. The current study was aimed to evaluate the prevalence and clinical significance of unrecognized renal dysfunction in patients with acute stroke. Methods The cohort consisted of patients with acute stroke included in the prospective National Acute Stroke ISraeli (NASIS) registry. Unrecognized renal insufficiency was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m² in the presence of serum creatinine ≤1.2 mg/dL. The 2 primary outcomes were in-hospital mortality and the composite of in-hospital mortality or severe disability at hospital discharge. Results Of the 7900 patients with stroke included in the study, 5571 (70.5%) had normal renal function, 1510 (19.1%) had recognized renal insufficiency, and 819 (10.4%) had unrecognized renal insufficiency. Mortality rates were higher in patients with recognized and unrecognized renal insufficiency compared with patients with normal renal function (9.9%, 9.1%, and 4.4%, respectively, P < .0001). Adjusted odds ratios (ORs) for in-hospital mortality were higher for patients with renal dysfunction recognized (OR, 2.1; 95% confidence interval [CI], 1.6-2.7; P < .001) or unrecognized (OR, 1.6; 95% CI, 1.1-2.2; P = .006) compared with patients with normal renal function. Likewise, adjusted ORs for the composite of in-hospital mortality or severe disability at hospital discharge were higher for patients with renal dysfunction recognized (OR, 1.3; 95% CI, 1.1-1.5; P = .004) or unrecognized (OR, 1.2; 95% CI, 1.01-1.5; P = .04). Conclusions Unrecognized renal insufficiency is common among patients with acute stroke and is associated with adverse short-term outcomes.