Timing, continuity, and energy dose of oral nutritional supplements in older coronary care unit patients: associations with prognostic nutritional index trajectory and hospitalization burden.

OBJECTIVES: Older adults account for a disproportionate share of coronary care unit (CCU) admissions, where acute cardiovascular instability, systemic inflammation, and nutritional deterioration converge. This single-center retrospective cohort study explored whether the timing, continuity, and daily energy dose of oral nutritional supplements (ONS) carry distinct associations with nutritional recovery and hospitalization burden in older CCU patients, to generate hypotheses for prospective investigation. METHODS: This single-center retrospective cohort study included 98 CCU patients (median age 80 years, IQR 73-86; 56.1% male) who received nutrition consultation-guided ONS between January 2023 and January 2026. Three delivery characteristics were examined: time from admission to ONS initiation, the ratio of ONS duration to total hospital stay, and average daily energy dose. Prognostic nutritional index (PNI) was tracked at admission, ONS initiation, and discharge or ONS cessation. Multivariable linear regression was used across three hierarchical models, supplemented by restricted cubic spline modeling and inverse probability weighting. RESULTS: PNI followed a V-shaped trajectory-declining from 37.65 ± 6.07 at admission to 35.24 ± 5.01 at ONS initiation, then rising to 36.26 ± 5.08 at discharge. Earlier initiation was independently associated with shorter hospital stay (β = 0.066 per day of delay, 95% CI: 0.043-0.088, p < 0.001) and lower total expenses (β = 0.056, p < 0.001). Greater continuity was similarly associated with reduced burden (β = -1.055, p < 0.001). Higher daily energy dose was associated with attenuated PNI improvement (β = -0.519 per 100 kcal/day, 95% CI: -0.801 to -0.237, p < 0.001). Initiation time and continuity were not significantly associated with PNI change. CONCLUSION: In this single-center exploratory cohort, the three ONS delivery features did not converge on the same recovery domain. Earlier initiation and sustained continuity were associated with lower hospitalization burden. Higher energy dose was associated with attenuated PNI improvement, a pattern likely reflecting confounding by indication, not a direct adverse effect of ONS energy. These exploratory associations suggest that timing and consistency in ONS delivery may warrant prospective evaluation alongside the decision to supplement. They do not establish causal relationships.