Purpose

The development of acute kidney injury (AKI) after the acute respiratory distress syndrome (ARDS) reduces the chance of organ recovery and survival. The purpose of this study was to examine the AKI rate and attributable mortality in ARDS patients.

Methods

We performed an individual patient-data analysis including 10 multicenter randomized controlled trials conducted over 20 years. We employed a Super Learner ensemble technique, including a time-dependent analysis, to estimate the adjusted risk of AKI. We calculated the mortality attributable to AKI using an inverse probability of treatment weighting estimator integrated with the Super Learner.

Results

There were 5148 patients included in this study. The overall incidence of AKI was 43.7% (n = 2251). The adjusted risk of AKI ranged from 38.8% (95% confidence interval [CI], 35.7 to 41.9%) in ARMA, to 55.8% in ROSE (95% CI, 51.9 to 59.6%). 37.1% recovered rapidly from AKI, with a significantly lower recovery rate in recent trials (P < 0.001). The 90-day excess in mortality attributable to AKI was 15.4% (95% CI, 12.8 to 17.9%). It decreased from 25.4% in ARMA (95% CI, 18.7 to 32%), to 11.8% in FACTT (95% CI, 5.5 to 18%) and then remained rather stable over time. The 90-day overall excess in mortality attributable to acute kidney disease was 28.4% (95% CI, 25.3 to 31.5%).

Conclusions

The incidence of AKI appears to be stable over time in patients with ARDS enrolled in randomized trials. The development of AKI remains a significant contributing factor to mortality. These estimates are essential for designing future clinical trials for AKI prevention or treatment.