Comparison of Tools for Nutrition Assessment in Stable Subjects with Chronic Obstructive Pulmonary Disease: Which is...

Malnutrition is associated with poor outcomes in chronic obstructive pulmonary disease (COPD), but the prognostic value of different nutritional assessment tools in outpatient settings remains unclear. We aimed to identify which of five commonly used nutritional indicators best predicts all-cause mortality in stable COPD in real-world clinical practice.

This secondary analysis of a prospective, hospital-based observational cohort included 141 outpatients with stable COPD. Nutritional status was assessed using body mass index (BMI), percent ideal body weight (%IBW), geriatric nutritional risk index (GNRI), prognostic nutritional index (PNI), and controlling nutritional status (CONUT) score. Patients were categorized as malnourished or well-nourished according to established cut-off values, including PNI <45 as a widely used threshold for malnutrition. Associations with all-cause mortality over a median follow-up of 54 months were examined using Cox proportional hazards models. Multivariate analyses adjusted for age, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, and COPD Assessment Test (CAT) score, and model fit was compared using Akaike's Information Criterion (AIC).

During follow-up, 29 deaths (20.6%) occurred. The proportion classified as malnourished ranged from 7.8% (PNI <45) to 25.5% (CONUT ≥2). In multivariate analyses, only PNI <45 remained significantly associated with mortality (adjusted hazard ratio 3.85; 95% confidence interval 1.33-11.13; p = 0.013) and provided the best AIC among the five tools. Kaplan-Meier curves demonstrated significantly poorer survival in the low PNI group (log-rank p < 0.001).

Among five simple nutritional assessment tools, only PNI independently predicted long-term mortality in stable COPD. Given its simplicity, objectivity, and reliance on routinely available laboratory parameters, PNI appears to be a practical marker to support risk stratification and guide proactive management in outpatient COPD care.