Prevalence and significance of unrecognized renal insufficiency in patients with heart failure

Renal insufficiency (RI) is a strong predictor of adverse outcome in patients with heart failure (HF). We aimed to determine the prevalence of RI being unrecognized and its significance in patients hospitalized with HF.

We analysed data from a prospective survey of 4102 hospitalized patients with HF. RI [defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2] was present in 2145 (57%) patients but, based on medical records, was unrecognized in 872 [41%, 95% confidence interval (CI) 39-43%] of them. Patients with unrecognized RI were more likely to be women, elderly, and with better functional class, compared with patients with recognized RI. In-hospital and 1 year mortality was significantly higher among patients with recognized and unrecognized RI compared with patients without RI: 6.5 and 7.1 vs. 2.1%, and 38.8 and 30.9 vs. 18.8% (P < 0.001), respectively. After adjustment, recognized and unrecognized RI comparably predicted increased in-hospital mortality: odds ratio (OR) and 95% CI of 2.34 (1.43-3.87), P < 0.001, and 2.30 (1.45-3.72), P < 0.001. After 1 year, recognized RI remained an independent predictor for mortality: OR 1.79 (1.45-2.20), P < 0.001, whereas there was a trend for increased mortality predicted by unrecognized RI: OR 1.22 (0.97-1.53), P = 0.08.

A high proportion of RI remains unrecognized among hospitalized patients with HF. As co-morbid RI has important prognostic and therapeutic implications, patients with HF may benefit from routine assessment of GFR.