Association of Acute Kidney Injury and Cardiovascular Disease Following Percutaneous Coronary Intervention: Assessment of Interactions by Race, Diabetes, and Kidney Function

Rationale & Objective Black patients and those with diabetes or reduced kidney function experience a disproportionate burden of acute kidney injury (AKI) and cardiovascular events. However, whether these factors modify the association between AKI and cardiovascular events after percutaneous coronary intervention (PCI) is unknown and was the focus of this study. Study Design Observational cohort. Setting & Participants Patients who underwent PCI at Duke between January 1, 2003, and December 31, 2013, with data available in the Duke Databank for Cardiovascular Disease. Exposure AKI, defined as ≥1.5-fold relative elevation in serum creatinine within 7 days from a reference value ascertained 30 days before PCI, or a 0.3 mg/dL increase from the reference value within 48 hours. Outcome A composite of all-cause death, myocardial infarction, stroke, or revascularization during the first year after PCI. Analytical Approach Cox regression models adjusted for potential confounders and with interaction terms between AKI and race, diabetes, or baseline estimated glomerular filtration rate (eGFR). Results Among 9,422 patients, 9% (n = 865) developed AKI, and the primary composite outcome occurred in 21% (n = 2,017). AKI was associated with a nearly 2-fold higher risk of the primary outcome (adjusted HR, 1.94 [95% CI, 1.71-2.20]). The association between AKI and cardiovascular risk did not significantly differ by race (P interaction, 0.4), diabetes, (P interaction, 0.06), or eGFR (P interaction, 0.2). However, Black race and severely reduced eGFR, but not diabetes, each had a cumulative impact with AKI on risk for the primary outcome. Compared with White patients with no AKI as the reference, the risk for the outcome was highest in Black patients with AKI (HR, 2.27 [95% CI, 1.83-2.82]), followed by White patients with AKI (HR, 1.87 [95% CI, 1.58-2.21]), and was least in patients of other races with AKI (HR, 1.48 [95% CI, 0.88-2.48]). Limitations Residual confounding, including the impact of clinical care following PCI on cardiovascular outcomes of AKI. Conclusions Neither race, diabetes, nor reduced eGFR potentiated the association of AKI with cardiovascular risk, but Black patients with AKI had a qualitatively greater risk than White patients with AKI or patients of other races with AKI. Plain-Language Summary This study examined differences by race, diabetes, or kidney function in the well-known association of AKI with increased risk for cardiovascular outcomes among patients undergoing percutaneous coronary intervention. The authors found that AKI was associated with a greater risk for cardiovascular outcomes, but this risk did not differ by patients’ race, diabetes status, or level of kidney function before the procedure. That said, the risk for cardiovascular outcomes was numerically highest among Black patients compared with White patients or those of other races. These study findings suggest that future efforts to prevent AKI among patients undergoing the procedure could reduce racial disparities in risk for unfavorable cardiovascular outcomes afterward. Black patients and those with diabetes or reduced kidney function experience a disproportionate burden of acute kidney injury (AKI) and cardiovascular events. However, whether these factors modify the association between AKI and cardiovascular events after percutaneous coronary intervention (PCI) is unknown and was the focus of this study. Observational cohort. Patients who underwent PCI at Duke between January 1, 2003, and December 31, 2013, with data available in the Duke Databank for Cardiovascular Disease. AKI, defined as ≥1.5-fold relative elevation in serum creatinine within 7 days from a reference value ascertained 30 days before PCI, or a 0.3 mg/dL increase from the reference value within 48 hours. A composite of all-cause death, myocardial infarction, stroke, or revascularization during the first year after PCI. Cox regression models adjusted for potential confounders and with interaction terms between AKI and race, diabetes, or baseline estimated glomerular filtration rate (eGFR). Among 9,422 patients, 9% (n = 865) developed AKI, and the primary composite outcome occurred in 21% (n = 2,017). AKI was associated with a nearly 2-fold higher risk of the primary outcome (adjusted HR, 1.94 [95% CI, 1.71-2.20]). The association between AKI and cardiovascular risk did not significantly differ by race (P interaction, 0.4), diabetes, (P interaction, 0.06), or eGFR (P interaction, 0.2). However, Black race and severely reduced eGFR, but not diabetes, each had a cumulative impact with AKI on risk for the primary outcome. Compared with White patients with no AKI as the reference, the risk for the outcome was highest in Black patients with AKI (HR, 2.27 [95% CI, 1.83-2.82]), followed by White patients with AKI (HR, 1.87 [95% CI, 1.58-2.21]), and was least in patients of other races with AKI (HR, 1.48 [95% CI, 0.88-2.48]). Residual confounding, including the impact of clinical care following PCI on cardiovascular outcomes of AKI. Neither race, diabetes, nor reduced eGFR potentiated the association of AKI with cardiovascular risk, but Black patients with AKI had a qualitatively greater risk than White patients with AKI or patients of other races with AKI.