LAUSR

Abstract Background Frailty is common among residential aged care services (RACS) residents; however, little is known about how frailty changes over time in this population. This study aimed to estimate minimally important difference (MID) in frailty to then describe: frailty change over 12 months; and factors associated with worsening frailty. Methods Prospective cohort study across 12 RACS sites of a single aged care organisation in South Australia (n = 548 residents, mean age 87.7 ± 7.2 years, 72.6% female). Frailty was measured using a frailty index (FI) with 12 months between baseline and follow-up. MID was calculated cross-sectionally (anchor-based using self-reported health, and ½SD for distribution-based). Results Between-person MID for the FI was identified as 0.037 (anchor-based) and 0.063 (distribution-based). Using the conservative value of 0.063 as the basis for change, 32.3% (n = 177) of residents remained stable, 13.7% (n = 75) improved, 33.0% (n = 181) worsened and 21.0% (n = 115) died over 12 months. In a multivariable analysis, significant predictors of the dichotomous outcome of worsening and death at 12 months were: being malnourished (odds ratio (OR) = 2.15, 95% confidence interval (CI) = 1.23, 3.75), at risk of malnutrition (OR = 1.98, 95%CI = 1.34, 2.91) and diabetes (OR = 1.61, 95%CI = 1.06, 2.42) compared to those who remained stable or improved. Conclusions A 6.3% change in frailty for RACS residents is a conservative MID. Frailty is dynamic in RACS residents, and stability or improvement was possible even for the most-frail. Treatments such as nutritional interventions, exercise and diabetes management are likely to benefit frailty.