Timing of AKI after urgent percutaneous coronary intervention and clinical outcomes: a high-dimensional propensity score analysis.

INTRODUCTION: Acute kidney injury is a common complication of percutaneous coronary intervention and has been associated with an increased risk of death and progressive chronic kidney disease. However, whether the timing of acute kidney injury after urgent percutaneous coronary intervention could be used to improve patient risk stratification is not known. METHODS: We conducted a retrospective cohort study in adults surviving an urgent percutaneous coronary intervention between 2008 and 2013 within Kaiser Permanente Northern California, a large integrated healthcare delivery system, to evaluate the impact of acute kidney injury during hospitalization at 12 (±6), 24 (±6) and 48 (±6) hours after urgent percutaneous coronary intervention and subsequent risks of adverse outcomes within the first year after discharge. We used multivariable Cox proportional hazards models with adjustment for a high-dimensional propensity score for developing acute kidney injury after percutaneous coronary intervention to examine the associations between acute kidney injury timing and all-cause death and worsening chronic kidney disease. RESULTS: Among 7250 eligible adults undergoing urgent percutaneous coronary intervention, 306 (4.2%) had acute kidney injury at one or more of the examined time periods after percutaneous coronary intervention. After adjustment, acute kidney injury at 12 (±6) hours was independently associated with higher risks of death (adjusted hazard ratio [aHR] 3.55, 95% confidence interval [CI] 2.19-5.75) and worsening kidney function (aHR 2.40, 95% CI:1.24-4.63). Similar results were observed for acute kidney injury at 24 (±6) hours and death (aHR 3.90, 95% CI:2.29-6.66) and worsening chronic kidney disease (aHR 4.77, 95% CI:2.46-9.23). Acute kidney injury at 48 (±6) hours was associated with excess mortality (aHR 1.97, 95% CI:1.19-3.26) but was not significantly associated with worsening kidney function (aHR 0.91, 95% CI:0.42-1.98). CONCLUSIONS: Timing of acute kidney injury after urgent percutaneous coronary intervention may be differentially associated with subsequent risk of worsening kidney function but not death.