Associations of estimated glucose disposal rate with frailty progression: results from two prospective cohorts

Frailty is a common geriatric syndrome associated with many adverse health outcomes. Identifying the risk factors of frailty is crucial and the insulin resistance (IR) is considered as a potential target. The estimated glucose disposal rate (eGDR) is a simple and reliable surrogate marker of IR. Associations of eGDR with frailty have not been explored. This study aimed to investigate the associations of eGDR with frailty progression. We used data from two prospective cohorts of the China Health and Retirement Longitudinal Study (CHARLS) and Health and Retirement Study (HRS). The eGDR was calculated as follows: eGDR (mg/kg/min) = 21.158 − (0.09×waist circumference) − (3.407×hypertension) − (0.551×glycosylated hemoglobin A1c) [waist circumference (cm), hypertension (yes = 1/no = 0), and glycosylated hemoglobin A1c (%)]. Participants were divided into three categories by tertiles of eGDR. Frailty index (FI) was calculated every two years and used to assess the degree of frailty which ranged from 0 to 100. Frailty progression was assessed by repeated measurements of FI during follow-up. Linear mixed-effect models were used to analyze the associations of eGDR with frailty progression. 8872 participants from CHARLS (mean age: 58.9 years, female: 53.3%) and 5864 participants from HRS (mean age: 67.0 years, female: 59.0%) were included. The median follow-up periods were 7.0 years in the CHARLS and 12.8 years in the HRS, respectively. Compared to participants with lower tertile (T1) of eGDR, those with upper tertile (T3) of eGDR showed decelerated FI progression (CHARLS, β: -0.294, 95%CI -0.390 to -0.198, P < 0.001; HRS, β: -0.378, 95%CI -0.474 to -0.281, P < 0.001). Continuous eGDR was also associated with FI progression for significant deceleration in FI progression with per 1 SD increase in eGDR (CHARLS, β: -0.142, 95%CI -0.181 to -0.103, P < 0.001; HRS, β: -0.170, 95%CI -0.209 to -0.130, P < 0.001). These associations were still observed after excluding baseline frail participants. Furthermore, the associations of eGDR with FI progression were consistent among participants with and without diabetes. Regardless of diabetes or not, a higher level of eGDR was associated with the decelerated frailty progression. Our findings highlight the role of eGDR in frailty progression and recommend taking effective interventions to improve eGDR for preventing frailty progression. The estimated glucose disposal rate and frailty progression. CHARLS, China Health and Retirement Longitudinal Study; HRS, Health and Retirement Study; eGDR, the estimated glucose disposal rate; FI, frailty index.