Prediagnosis frailty and survival after cancer in middle-aged and older adults: a population-based cohort study.

When modeled continuously, each 0.01-unit increase in frailty index was associated with an approximately 2% higher mortality risk (HR 1.02, 95% CI 1.01-1.03).

At baseline, 740 participants (39.3%) were younger than 65 years, whereas 1,142 participants (60.7%) were aged 65 years or older.

Age-stratified fully adjusted weighted Cox analyses demonstrated that each 0.01-unit increment in frailty index was associated with elevated mortality in the total population (HR 1.022, 95% CI 1.015-1.030; P < 0.001), adults aged ≥ 65 years (HR 1.017, 95% CI 1.008-1.026; P < 0.001), and participants < 65 years (HR 1.023, 95% CI 1.011-1.036; P = 0.003).