Acute Kidney Injury Among Older Patients Undergoing Coronary Angiography for Acute Myocardial Infarction: The SILVER-AMI Study.

BACKGROUND

Among older adults (age ≥75 years) hospitalized for acute myocardial infarction, acute kidney injury after coronary angiography is common. Aging-related conditions may independently predict acute kidney injury, but have not yet been analyzed in large acute myocardial infarction cohorts.

METHODS

We analyzed data from 2212 participants age ≥75 years in the Comprehensive Evaluation of Risk Factors in Older Patients with Acute Myocardial Infarction (SILVER-AMI) study who underwent coronary angiography. Acute kidney injury was defined using Kidney Disease Improving Global Outcomes (KDIGO) criteria (serum Cr increase ≥0.3 mg/dL from baseline or ≥1.5 times baseline). We analyzed the associations of traditional acute kidney injury risk factors and aging-related conditions (activities of daily living impairment, prior falls, cachexia, low physical activity) with acute kidney injury, and then performed logistic regression to identify independent predictors.

RESULTS

Participants' mean age was 81.3 years, 45.2% were female, and 9.5% were nonwhite; 421 (19.0%) experienced acute kidney injury. Comorbid diseases and aging-related conditions were both more common among individuals experiencing acute kidney injury. However, after multivariable adjustment, no aging-related conditions were retained. There were 11 risk factors in the final model; the strongest were heart failure on presentation (odds ratio [OR] 1.91; 95% confidence interval [CI], 1.41-2.59), body mass index [BMI] >30 (vs BMI 18-25: OR 1.75; 95% CI, 1.27-2.42), and nonwhite race (OR 1.65; 95% CI, 1.16-2.33). The final model achieved an area under the receiver operating characteristic curve of 0.72 and was well calibrated (Hosmer-Lemeshow P = .50). Acute kidney injury was independently associated with 6-month mortality (OR 1.98; 95% CI, 1.36-2.88) but not readmission (OR 1.26; 95% CI, 0.98-1.61).

CONCLUSIONS

Acute kidney injury is common among older adults with acute myocardial infarction undergoing coronary angiography. Predictors largely mirrored those in previous studies of younger individuals, which suggests that geriatric conditions mediate their influence through other risk factors.