Long-term risk of coronary events after AKI

Abstract

The incidence rate of AKI in hospitalized patients is increasing. However, relatively little attention has been paid to the association of AKI with long-term risk of adverse coronary events. Our study investigated hospitalized patients who recovered from de novo dialysis-requiring AKI between 1999 and 2008 using patient data collected from inpatient claims from Taiwan National Health Insurance. We used Cox regression with time-varying covariates to adjust for subsequent CKD and ESRD after discharge. Results were further validated by analysis of a prospectively constructed database. Among 17,106 acute dialysis patients who were discharged, 4869 patients recovered from dialysis-requiring AKI (AKI recovery group) and were matched with 4869 patients without AKI (non-AKI group). The incidence rates of coronary events were 19.8 and 10.3 per 1000 person-years in the AKI recovery and non-AKI groups, respectively. AKI recovery associated with higher risk of coronary events (hazard ratio [HR], 1.67; 95% confidence interval [95% CI], 1.36 to 2.04) and all-cause mortality (HR, 1.67; 95% CI, 1.57 to 1.79) independent of the effects of subsequent progression to CKD and ESRD. The risk levels of de novo coronary events after hospital discharge were similar in patients with diabetes alone and patients with AKI alone (P=0.23). Our results reveal that AKI with recovery associated with higher long-term risks of coronary events and death in this cohort, suggesting that AKI may identify patients with high risk of future coronary events. Enhanced postdischarge follow-up of renal function of patients who have recovered from temporary dialysis may be warranted.

Figure 1.

Flow diagram of selecting study subjects. Creation of the Acute Kidney Injury and Dialysis Study cohort. pt, patient.

Figure 2.

Future 10-year probability of freedom from coronary events based on different scenarios of morbid conditions. After obtaining the Cox regression equation, we estimated the hazard function along with time. Based on this hazard function, the probability of freedom from coronary events under different scenarios of morbid conditions with regard to DM, AKI, CKD, and ESRD was conducted in simulation to depict 10-year survival curves.

Figure 3.

Coronary events stratified by DM and AKI. (A) Adjusted HRs for long-term risk of coronary events based on comparison among patient groups stratified by status of DM and AKI that selected patients having DM alone as the reference group and adjusted for propensity score, age, sex, premorbid risk, comorbidities, and subsequent time-varying CKD and ESRD after hospital discharge. 95% CI, 95% confidence interval. *P<0.005; ^#P<0.001. (B) Conditional effect plot showing the relationships of age, DM, and AKI with the incidence probability of coronary events during follow-up with adjustment for propensity score, sex, premorbid risk, and comorbidities based on the fitted multiple logistic regression model.

Figure 4.

Risk of coronary events associated with AKI by participant characteristics. Adjusted HRs for long-term risk of coronary events based on comparison between the AKI dialysis recovery and non-AKI groups and subgroup analysis with respect to baseline comorbidity that further adjusted for age, sex, and propensity score. 95% CI, 95% confidence interval; COPD, chronic obstructive pulmonary disease; ICU, intensive care unit.