Hospital readmissions after acute kidney injury: a systematic review and meta-analysis

Background and aims: Acute kidney injury (AKI) is a great burden not only during hospitalization but also after hospital discharge. The objective of this meta-analysis was to evaluate the hospital readmission rates and the mortality after survival of AKI. Methods: Pubmed, Web of Science, Cochrane Library, OVID and EMBASE databases through November 2015 were searched to identify studies reporting hospital readmission rates after AKI. The primary outcome were hospital readmission rates during 30-day, 60-day, 90-day and 1-year after discharge. And the mortality rates within 30-day and 1-year were also identified. Results: Eleven studies were eligible for inclusion. The pooled 30-day hospital readmission rates were 21.0% (95% confidence interval [CI], 16.3%-26.8%) in AKI group and 10.9% (95% CI, 9.7%-12.1%) in Non-AKI group, while the pooled 1-year rates were 48.0% (95% CI, 34.9%-61.3%) and 27.9% (95% CI, 16.3%-43.5%), respectively. The pooled unadjusted odds ratio (OR) for 30-day and 1-year hospital readmission in patients with AKI was 0.536 (95% CI, 0.443 to 0.649) and 0.453 (95% CI, 0.310 to 0.663), respectively, compared to patients without AKI (P = 0.000). The pooled 30-day post-discharge mortality was 10.7% in AKI group and 2.3% in Non-AKI group (P = 0.001), respectively, while the pooled 1-year mortality was 33.2% in AKI group and 13.8% in Non-AKI group (P = 0.000). Conclusions: There is a higher risk of short and long-term hospital readmission and death in patients who have survived the initial onset of AKI compared to Non-AKI patients. These patients deserve more attention after hospital discharge.