A convenient calf proportion index calculator for survival prediction in overweight and obese patients with cancer.

OBJECTIVE

This study aimed to define the calf proportion index (CPI) and investigate its association with malnutrition and survival in overweight and obese patients with cancer.

METHODS

This multicenter observational cohort study included 3499 patients diagnosed with cancer, including 3145 overweight and 354 obese individuals. The CPI was defined as the ratio of the cross-sectional area of the calf circumference (CC) to the body surface area (BSA). A CPI calculator that automatically calculated the CPI and survival probability based on the patient's sex, height, weight, and CC was developed.

RESULTS

During a median follow-up of 44.1 months, 935 deaths were recorded. Receiver operating characteristic curves revealed that the CPI was better than CC and BSA as a predictor of survival, with AUCs for the 3-year mortality rate were 0.574, 0.553 and 0.529, respectively. In overweight and obese patients with cancer, the optimal CPI cut-off value was 0.65 % for men and 0.57 % for women. The Kaplan-Meier curve revealed that patients with a low CPI had lower survival. After adjusting confounding factors, a low CPI was an independent risk factor for overweight (hazard ratio [HR]: 1.29, 95 % confidence interval [CI]: 1.11-1.51, P < 0.001) and obesity (HR: 1.92, 95 % CI: 1.20-3.09, P = 0.007) in patients with cancer. The CPI exhibited significant prognostic value in patients with lung and digestive system cancers. The risk of malnutrition was significantly higher in patients with a low CPI (HR: 1.25, 95 % CI: 1.04-1.50, P = 0.019).

CONCLUSIONS

The CPI is a useful prognostic indicator in overweight and obese patients with cancer, especially in obese patients.