Telomere length, comorbidity, functional, nutritional and cognitive status as predictors of 5 years post hospital discharge survival in the oldest old

Abstract

Telomere length has been considered in many cross-sectional studies as a biomarker of aging. However the association between shorter telomeres with lower survival at advanced ages remains a controversial issue. This association could reflect the impact of other health conditions than a direct biological effect. To test whether leukocyte telomere length is associated with 5-year survival beyond the impact of other risk factors of mortality like comorbidity, functional, nutritional and cognitive status. Prospective study. A population representative sample of 444 patients (mean age 85 years; 74% female) discharged from the acute geriatric hospital of Geneva University Hospitals (January–December 2004), since then 263 (59.2%) had died (December 2009). Telomere length in leukocytes by flow cytometry. In univariate model, telomere length at baseline and cognitive status were not significantly associated with mortality even when adjusting for age (R2=9.5%) and gender (R2=1.9%). The best prognostic predictor was the geriatric index of comorbidity (GIC) (R2=8.8%; HR=3.85) followed by more dependence in instrumental (R2=5.9%; HR=3.85) and based (R2=2.3%; HR=0.84) activities of daily living and lower albumin levels (R2=1.5%; HR=0.97). Obesity (BMI>30: R2=1.6%; HR=0.55) was significantly associated with a two-fold decrease in the risk of mortality compared to BMI between 20–25. When all independent variables were entered in a full multiple Cox regression model (R2=21.4%), the GIC was the strongest risk predictor followed by the nutritional and functional variables. Neither telomeres length nor the presence of dementia are predictors of survival whereas the weight of multiple comorbidity conditions, nutritional and functional impairment are significantly associated with 5-year mortality in the oldest old.