Relationship between the prognostic nutritional index and long-term clinical outcomes in patients with stable coronary artery disease

Background: Malnutrition has recently been reported to correlate with prognosis in patients with heart failure. However, the prognostic significance of nutritional status in patients with stable coronary artery disease (CAD) is unknown. The present study sought to examine the association between nutritional status assessed by the prognostic nutritional index (PNI) and cardiovascular outcomes in patients with stable CAD.

Methods: A total of 1988 patients with stable CAD who underwent elective percutaneous coronary intervention (PCI) between 2000 and 2011 were examined. The PNI was calculated as 10×serum albumin (g/dL)+0.005×total lymphocyte count (per mm³). Patients were assigned to tertiles based on their PNI. The incidence of major adverse cardiac events (MACE), including all-cause death and non-fatal myocardial infarction, was evaluated.

Results: The median PNI was 48.9 (interquartile range: 45.5-52.1). During the median follow-up of 7.5 years, Kaplan-Meier analysis showed that patients with lower PNI tertiles had higher rates of MACE (PNI <46.7: 35.5%; 46.7-50.8: 22.3%; >50.8: 16.0%; log-rank p<0.0001). After adjusting for other risk factors, the PNI was independently associated with MACE (hazard ratio 2.05 per 10 PNI decrease, 95% confidence interval: 1.66-2.54, p<0.0001). Adding the PNI to a baseline model with established risk factors improved the C-index (p=0.03), net reclassification improvement (p=0.03), and integrated discrimination improvement (p=0.0001).

Conclusions: The PNI was significantly associated with long-term cardiovascular outcomes in patients with stable CAD. Assessing PNI may be useful for risk stratification of CAD patients undergoing elective PCI.