THE RELATIONSHIP BETWEEN DISEASE AND FUNCTION AND PERCEIVED HEALTH INVERY FRAIL ELDERS

Objective: To study associations between disease and observed function and self-perceived health in very frail elders. Design and Setting: C ross-sectional survey of nine nursing homes in San Antonio, TX. Partic ipants: 194 elderly long-stay nursing home residents dependent in at l east two ADLs and without severe cognitive impairment. Measures: Burde n of disease (BOD) was chart abstracted using a standardized protocol that assessed types and severities of 59 categorizations of chronic an d acute medical conditions. Observed function and self-perceived healt h status were assessed independently by the Katz Activities of Daily L iving scale (ADL) and the Sickness Impact Profile (SIP), respectively. Results: Summary BOD scores had a low, but statistically significant, univariate correlation with ADL scores (r = 0.21, P = 0.003) and no s ignificant correlation with SIP scores (R = -0.008). Multiple linear r egression analyses, including the 24 most frequent disease categories, showed that disease explained significant amounts of ADL (r2 = 0.25, P = 0.001) and borderline significant amounts of SIP (r2 = 0.16, P = 0 .11). Models including both disease and sociodemographic, cognitive, a nd affective variables showed disease added significant incremental ex planation beyond the other factors to ADL (incremental r2 = 0.14, P = 0.04), but not to SIP (incremental r2 = 0.08, P > 0.10). Conclusions: Disease, observed function, and self-perceived health status are separ ate, but interrelated entities, with disease having a stronger relatio nship to observed function than self-perceived health. Comprehensive a ssessment of frail elders may need to include all three areas, and stu dies that focus on one area should take into account the other two as potential important covariates.