The association between frailty biomarkers and 20-year all-cause and cardiovascular mortality among community-dwelling older adults

Abstract

ABSTRACT Objectives While several biomarkers were previously associated with frailty and mortality, data are still contradicting. We aimed to evaluate the association between novel biomarkers and frailty among community-dwelling older adults to enhance understanding of the pathophysiology of frailty. Methods Nine hundred and sixty-three older adults were screened during the third phase (1999–2008) of the Israel study on Glucose Intolerance, Obesity, and Hypertension (GOH). Frailty was defined as sedentary individuals, past 10 years hospitalizations, or at least one of the following: body mass index (BMI) <21 kg/m2; albumin <3.2 g/dl; ≥2 major baseline diseases. Biomarkers were evaluated for their association with frailty, all-cause, and cardiovascular mortality. Results Mean baseline age was 72 ± 7 years, 471 (49%) were women, and 195 (20%) were classified as frail. Median follow-up for cardiovascular and all-cause mortality was 11 and 13 years, with 179 (18.6%) and 466 (48.4%) deaths recorded, respectively. Multivariable logistic regression showed greater odds for frailty with lower quartile of alanine aminotransferase (ALT) (OR = 1.8, 95%CI: 1.2–2.8, p = 0.01), and for each 5 µmol/L increment in homocysteine levels (OR = 1.3, 95%CI: 1.1–1.5, p = 0.001). Multivariate Cox regression showed greater all-cause and cardiovascular mortality risk for individuals with low ALT (HR = 1.6, 95%CI: 1.3–2.0, p < 0.001 and HR = 1.5, 95% CI: 1.0–2.2, p = 0.03, respectively), and high homocysteine (HR = 1.1, 95%CI: 1.1–1.3, p = 0.003 and HR = 1.2, 95%CI: 1.0–1.3, p = 0.04, respectively). Homocysteine association with mortality was more pronounced in those with baseline ischemic heart disease (IHD) compared with subjects free of IHD (P for interaction = 0.01). Conclusions Lower ALT and higher homocysteine were associated with frailty, all-cause and cardiovascular mortality. These available and low-cost biomarkers underscore the nutritional and metabolic aspects of frailty when screening high-risk older adults, especially those with IHD, and may be considered as preferable screening biomarkers to be tested among these individuals for frailty and mortality risk.