Nonrecovery of kidney function and death after acute on chronic renal failure

Abstract

Background and objectives: Relatively little is known about clinical outcomes, especially long-term outcomes, among patients who have chronic kidney disease (CKD) and experience superimposed acute renal failure (ARF; acute on chronic renal failure).

Design, setting, participants, & measurements: We tracked 39,805 members of an integrated health care delivery system in northern California who were hospitalized during 1996 through 2003 and had prehospitalization estimated GFR (eGFR) <45 ml/min per 1.73 m(2). Superimposed ARF was defined as having both a peak inpatient serum creatinine greater than the last outpatient serum creatinine by > or =50% and receipt of acute dialysis.

Results: Overall, 26% of CKD patients who suffered superimposed ARF died during the index hospitalization. There was a high risk for developing ESRD within 30 d of hospital discharge that varied with preadmission renal function, being 42% among hospital survivors with baseline eGFR 30-44 ml/min per 1.73 m(2) and 63% among hospital survivors with baseline eGFR 15-29 ml/min per 1.73 m(2). Compared with patients who had CKD and did not experience superimposed ARF, those who did had a 30% higher long-term risk for death or ESRD.

Conclusions: In a large, community-based cohort of patients with CKD, an episode of superimposed dialysis-requiring ARF was associated with very high risk for nonrecovery of renal function. Dialysis-requiring ARF also seemed to be an independent risk factor for long-term risk for death or ESRD.

Figure 1.

Outcomes among 39,805 hospitalized patients with chronic kidney disease (CKD) and preadmission estimated GFR (eGFR) <45 ml/min per 1.73 m² (acute renal failure [ARF] is defined ≥50% increase in serum creatinine and receipt of inpatient acute dialysis).

Figure 2.

Outcomes during and immediately after hospitalization for patients who had CKD and did or did not experience an episode of superimposed ARF, stratified by level of preadmission eGFR (all P < 0.01 for trend across GFR categories).

Figure 3.

Long-term ESRD-free survival (absence of death or ESRD) among patients who had CKD and who did not develop ESRD or death within 30 d of discharge from index hospitalization. Dashed line represents those who experienced superimposed ARF (n = 213); solid line represents those who did not (n = 34,721).