Aim
This study investigates whether admission lipid levels, specifically HDL-C versus LDL-C, independently predict the length of stay (LOS) in an age-stratified cohort.Methods: A single-center retrospective cohort study was conducted with 216 patients (minimum LOS of 3 days) included in the final analysis. The cohort was stratified into two age groups: younger adults (<65 years, n=80, 37.0%) and seniors (>= 65 years, n=136, 63.0%). To account for the strictly positive, right-skewed distribution of LOS, Generalized Linear Models (GLM) utilizing a Gamma probability distribution with a logarithmic link function were employed to calculate Incidence Rate Ratios (IRR). Multivariable models were adjusted for demographics, comorbidities (HF, DM2, HT), frailty markers (HGB, admission RDW), and pre-admission lipid-lowering therapy (LLT).Results: Geriatric patients exhibited a significantly longer median LOS (7.0 vs. 5.0 days, p < 0.001). Multivariable GLM Gamma analysis confirmed that in geriatric patients, admission HDL-C was a strong, independent, and inverse predictor of LOS (IRR = 0.994, p = 0.005). Clinically, every 10 mg/dL decrease in HDL-C independently prolonged the expected hospital stay by approximately 6.2%. Conversely, admission LDL-C (IRR = 1.001, p = 0.431) and LLT use (IRR = 0.988, p = 0.891) offered no prognostic value. In the younger cohort, neither HDL-C nor LDL-C predicted LOS (p = 0.165 and p = 0.780, respectively), confirming the strictly age-specific nature of this lipid paradox.Discussion: The prognostic value of lipid profiles during acute hospitalization is highly age-dependent, validating the clinical relevance of the "lipid paradox" in geriatric care. While standard LDL-C levels offer no predictive insight for short-term recovery, low admission HDL-C independently predicts prolonged hospital stays exclusively in patients aged 65 and older, irrespective of concurrent statin therapy. This suggests that HDL-C acts as a vital surrogate marker for assessing acute illness severity and physiological reserve in the elderly.
