Methods: Variables in 5 domains—demographics, pain/arthritis, physical/social constraints, depression, and affect—were assessed as potential predictors of change over time in perceived GH, PH, and EH. Demographic characteristics were examined as moderators. Data included baseline and 2-year follow-up survey data from 8 cohorts in the Medicare Health Outcomes Study between 2004 and 2014 (N=1,148,284 observations from 786,596 individuals). Linear mixed effect models were used to account for the nested structure of the data and control for cohort effects. Effect sizes were calculated for all hypothesized predictors.
Results: White race, higher education level, lower physical limitation, and higher perceived energy level predicted increases in GH over time. None of the predictors except EH predicted PH. Improvements in EH were positively associated with changes in PH. Higher levels of depression predicted declines in EH. Age, race, and gender did not moderate the above associations.
Conclusion: Low physical limitations and high energy level appear to be the strongest predictors of improved GH over time, suggesting that rehabilitative treatments to overcome and reduce physical limitations and maximize energy should be healthcare priorities. The strong correlation between PH and EH and the strong contribution of depression to EH indicate that depression treatment should be a medical priority to maintain both PH and EH over the lifecourse. The stronger decline in GH over time among minorities and people with lower education provides evidence for health disparities. Increased focus on global health self-rating measures could allow practitioners to individualize treatment plans and identify gaps in services.