Low body mass index, serum creatinine, and cause of death in patients undergoing percutaneous coronary intervention

Background-Low body mass index (BMI) and serum creatinine are surrogate markers of frailty and sarcopenia. Their relationship with cause-specific mortality in elderly patients undergoing percutaneous coronary intervention is not well studied. Methods and Results-We determined long-term cardiovascular and noncardiovascular mortality in 9394 consecutive patients aged ≥65 years who underwent percutaneous coronary intervention from 2000 to 2011. BMI and serum creatinine were divided into 4 categories. During a median follow-up of 4.2 years (interquartile range 1.8-7.3 years), 3243 patients (33.4%) died. In the multivariable model, compared with patients with normal BMI, patients with low BMI had significantly increased all-cause mortality (hazard ratio [HR] 1.4, 95% CI 1.1-1.7), which was related to both cardiovascular causes (HR 1.4, 95% CI 1.0-1.8) and noncardiovascular causes (HR 1.4, 95% CI 1.06-1.9). Compared with normal BMI, significant reduction was noted in patients who were overweight and obese in terms of cardiovascular mortality (overweight: HR 0.77, 95% CI 0.67-0.88; obese: HR 0.80, 95% CI 0.70-0.93) and noncardiovascular mortality (overweight: HR 0.85, 95% CI 0.74-0.97; obese: HR 0.82, 95% CI 0.72-0.95). In a multivariable model, in patients with normal BMI, low creatinine (≤0.70 mg/dL) was significantly associated with increased all-cause mortality (HR 1.8, 95% CI 1.3-2.5) and cardiovascular mortality (HR 2.3, 95% CI 1.4-3.8) compared with patients with normal creatinine (0.71-1.0 mg/dL); however, this was not observed in other BMI categories. Conclusions-We identified a new subgroup of patients with low serum creatinine and normal BMI that was associated with increased all-cause mortality and cardiovascular mortality in elderly patients undergoing percutaneous coronary intervention. Low BMI was associated with increased cardiovascular and noncardiovascular mortality. Nutritional support, resistance training, and weight-gain strategies may have potential roles for these patients undergoing percutaneous coronary intervention.