Worsening renal function definition is insufficient for evaluating acute renal failure in acute heart failure

Abstract

Aims: Whether or not the definition of a worsening renal function (WRF) is adequate for the evaluation of acute renal failure in patients with acute heart failure is unclear.

Methods and results: One thousand and eighty-three patients with acute heart failure were analysed. A WRF, indicated by a change in serum creatinine ≥0.3 mg/mL during the first 5 days, occurred in 360 patients while no-WRF, indicated by a change <0.3 mg/dL, in 723 patients. Acute kidney injury (AKI) upon admission was defined based on the ratio of the serum creatinine value recorded on admission to the baseline creatinine value and placed into groups based on the degree of AKI: no-AKI (n = 751), Class R (risk; n = 193), Class I (injury; n = 41), or Class F (failure; n = 98). The patients were assigned to another set of four groups: no-WRF/no-AKI (n = 512), no-WRF/AKI (n = 211), WRF/no-AKI (n = 239), and WRF/AKI (n = 121). A multivariate logistic regression model found that no-WRF/AKI and WRF/AKI were independently associated with 365 day mortality (hazard ratio: 1.916; 95% confidence interval: 1.234-2.974 and hazard ratio: 3.622; 95% confidence interval: 2.332-5.624). Kaplan-Meier survival curves showed that the rate of any-cause death during 1 year was significantly poorer in the no-WRF/AKI and WRF/AKI groups than in the WRF/no-AKI and no-WRF/no-AKI groups and in Class I and Class F than in Class R and the no-AKI group.

Conclusions: The presence of AKI on admission, especially Class I and Class F status, is associated with a poor prognosis despite the lack of a WRF within the first 5 days. The prognostic ability of AKI on admission may be superior to WRF within the first 5 days.

Keywords: Acute decompensated heart failure; Acute kidney injury; Acute renal failure; Cardio renal syndrome; RIFLE criteria.

Figure 1

This study examined (i) the relationship between the worsening renal function (WRF) and/or acute kidney injury (AKI) on admission and the outcomes and (ii) the relationship between the degree of AKI on admission and the outcomes. This is the scheme of the group assignment. (A) The patients were assigned to four categories based on the WRF and AKI on admission: The no‐AKI patients who did not develop WRF during the first 5 days were assigned to no‐WRF/no‐AKI group (n = 512), and the no‐AKI patients who developed WRF were assigned to WRF/no‐AKI group (n = 239). The AKI patients who did not develop WRF during the first 5 days were assigned to no‐WRF/AKI (n = 211) groups, and the AKI patients who developed WRF were assigned to WRF/AKI group (n = 121) groups. (B) The patients were assigned to four categories based on the degree of AKI: No AKI was present in 751 patients, and AKI was present upon admission in 332 patients including Class R (risk; n = 193), Class I (injury; n = 41), or Class F (failure; n = 98).

Figure 2

Kaplan–Meier curves based on the presence of a worsening renal function (WRF) or acute kidney injury (AKI). (A) The all‐cause death rate was significantly poorer in the WRF/AKI group than in the no‐WRF/AKI, WRF/no‐AKI, and no‐WRF/no‐AKI groups and in the no‐WRF/AKI group than in the WRF/no‐AKI and no‐WRF/no‐AKI groups. (B) The prognosis, including the likelihood of a heart failure (HF) event, was significantly poorer in the WRF/AKI group than in the no‐WRF/AKI, WRF/no‐AKI, and no‐WRF/no‐AKI groups.

Figure 3

Kaplan–Meier curves regarding the degree of acute kidney injury (AKI). (A and B) The Kaplan–Meier survival curves showed the prognosis, including likelihood of all‐cause death and heart failure (HF) events, to be significantly poorer in the Class I than in the no‐AKI and Class R groups and to be significantly poorer in the Class F patients than in the patients in the no‐AKI and Class R groups.