Effects of early recovery of renal function on adverse renal outcomes and mortality in patients with acute kidney injury: a systematic review and meta-analysis

Abstract

Aim: This study intended to scrutinize the effect of RFR time on adverse renal outcomes and mortality and try to define the cutoff of early RFR.

Methods: We conducted a literature search from database inception to February 2023. Outcome measures incorporated the progression of CKD, delivery of RRT, incidence of composite renal outcomes, and mortality. And pooled results were depicted as odds ratio (OR) and 95% confidence interval (CI).

Results: A total of 11 studies were finally selected (507,989 patients, mean follow-up, 3.89 years). The results exhibited that the crude mortality was lower in patients with early RFR (OR = 0.39, 95% CI: 0.16-0.95, P = 0.037). In addition, patients with early RFR had a lower incidence of progression to CKD (OR = 0.38, 95% CI: 0.17-0.85, P < 0.018), RRT (OR = 0.37, 95% CI: 0.20-0.71, P = 0.03), and composite renal outcomes (OR = 0.18, 95% CI: 0.15-0.20, P < 0.001). CKD progression-related events were significantly higher in patients whose renal function recovered after 7 days (OR = 0.69, 95% CI: 0.47-1.09, P = 0.112) than in those whose renal function recovered within 7 days (OR = 0.23, 95% CI: 0.06-0.92, P = 0.038), and the risk of RRT was lower in patients who recovered within 7 days (OR = 0.32, 95% CI: 0.15-0.66, P = 0.002) than in those who recovered after 7 days (OR = 0.72, 95% CI: 0.17-3.09, P = 0.654) or longer.

Conclusion: Patients with early RFR had a lower risk of CKD progression, RRT, and composite renal outcomes, as well as lower crude mortality than those without early recovery, despite no marked difference in 30-day, 90-day, and 1-year mortality. We speculated that 7 days may be used as a cutoff for early RFR.

Keywords: Acute kidney injury; Early recovery of renal function; Long-term outcome; Meta-analysis; Systematic review.