Association between chronic inflammation and poorer long-term functional recovery post-hip fracture in and between men and women

Abstract Mechanisms underlying functional recovery after hip fracture have not been widely studied in either sex, but particularly not in men. Cytokines, or biomarkers of inflammation in the blood, are associated with declines in function post hip fracture in women. Therefore, the aim of this study was to examine chronic systemic inflammation, as measured by cytokines, and its association with function and functional recovery post-hospitalization within and between the sexes. In the sample, with equal proportions of men and women, cytokines were measured at baseline, 2, 6, and 12 mo post-hip fracture, including IL1-ra, IL-6, and sTNFα-R1 levels. The Short Physical Performance Battery (SPPB) was measured at 2 and 6 mo. Participants were divided into tertiles based on their 2-mo cytokine levels. Longitudinal regression models were used to examine the change in cytokine levels over the year by sex, and to model the association of cytokine tertiles and physical function. Older adults (n = 311, 50% men, age 80.9 ± 7.5 yr) were included. Men had higher levels of IL-6 and sTNFα-R1 at 2, 6, and 12 mo. Lower 2-mo cytokine levels were associated with better function at 2 mo and better recovery of function at 6-mo. Women in the lowest tertile of IL-6 and sTNFα-R1 at 2 mo had higher SPPB scores (all p ≤ .03) than men in the middle and upper tertiles, and these findings persisted at 6 mo. Furthermore, women in the lowest tertile of IL1-ra had better recovery in the SPPB than men in all tertiles at 6 mo (p ≤ .03). Lower levels of systemic inflammation were associated with better functional performance at 2 mo and functional recovery at 6 mo post hip fracture. The between sex differences in cytokines and functional recovery suggest that medical management and rehabilitation strategies may need to be adapted by sex and with attention to specific inflammatory biomarkers.