Risk Factors and Prognostic Effects of Refeeding Syndrome in Malnourished Elderly Patients During Nutritional Support

Refeeding syndrome (RFS) is a life-threatening metabolic complication arising when malnourished or catabolic patients resume nutrient intake, defined primarily by hypophosphatemia and concurrent electrolyte disturbances. Among malnourished elderly, RFS has an incidence of ∼50% and is linked to extremely high mortality.

This retrospective case-control study included 93 elderly patients (≥ 60 y) with a Nutrition Risk Screening 2002 (NRS 2002) score ≥ 3, admitted to two tertiary hospitals between August 2017 and August 2019. Patients were retrospectively assigned to the "RFS group" (n = 42, developed RFS within 1 week of admission) and a non-RFS group (n = 51).

Independent RFS risk factors were low BMI (18.24 ± 1.66 vs. 22.06 ± 1.84 kg/m²), low serum albumin (29.97 ± 3.16 vs. 35.29 ± 4.33 g/L), and high D-dimer (5.02 ± 1.87 vs. 2.34 ± 2.00 μg/mL; all p < 0.05). RFS patients had a significantly poorer prognosis: longer hospital stay (28.74 ± 9.02 vs. 16.84 ± 8.57 d), lower 28-day (47.6% vs. 84.3%), and 90-day (28.6% vs. 56.9%) survival rates, and higher organ dysfunction incidence (all p < 0.05). Within patients diagnosed with RFS, stepwise nutritional therapy contributed to better clinical outcomes. Among all enrolled high-risk elderly individuals, nutritional regimens combined with phosphate, magnesium, potassium, vitamin B1 (thiamine) supplementation, and appropriate energy restriction effectively alleviated RFS severity and related complications. Subgroup analysis of RFS patients further confirmed that combined micronutrient supplementation shortened hospital stay and improved 90-day survival.

Universal micronutrient supplementation at admission combined with targeted energy restriction within the first 10-14 days of hospitalization reduces RFS risk among vulnerable elderly inpatients. Notably, multimicronutrient supplementation exerts a stronger protective effect against RFS than feeding route or initial energy regimen. Low BMI, hypoalbuminemia, and elevated D-dimer serve as reliable predictors of RFS. Stepwise nutritional intervention with prompt electrolyte correction can shorten hospital stay and enhance 90-day survival.