Occult renal insufficiency: creatinine clearance as an indicator of outcome in acute decompensated heart failure patients

Objective

The aim of this analysis was to evaluate whether renal function estimated by calculated creatinine clearance may add information in order to stratify the mortality and length of stay in patients with acute decompensated heart failure.

Methods

We conducted a retrospective review of the records of 766 inpatients hospitalized with heart failure. Renal function was categorized as normal renal function (NRF) (serum creatinine ≤ 1.1 mg/dl and creatinine clearance >60 ml/min), occult renal insufficiency (ORI) (serum creatinine ≤ 1.1 mg/dl and creatinine clearance ≤ 60 ml/min), mild renal insufficiency (MRI) (1.1 mg/dl <serum creatinine ≤ 1.5 mg/dl and creatinine clearance <60 ml/min) or moderate to severe renal insufficiency (MSRI) (serum creatinine >1.5 mg/dl and creatinine clearance <60 ml/min).

Results

Out of 765 patients in the sample, 174 (22.71%) had normal renal function, 205 (26.76%) had mild RI, 260 (33.94%) had moderate to severe RI, and 126 (16.45%) had occult renal insufficiency. The mortality rates were: 3.4% (NRF), 3.4% (MRI) – P = NS vs NRF, 7.9% (ORI) – P = 0.05 versus NRF, and 13% (MSRI) – P < 0.05 versus NRF. Lengths of stay were different among the groups: MRI 12 days, ORI 14 days, and MSRI 16 days (P < 0.05 between groups).

Conclusion

The calculated creatinine clearance added information in order to stratify risk in heart failure patients requiring hospitalization. By identifying patients with ORI, creatinine clearance helped to find patients at risk not shown when only serum creatinine was used.