THE IMPACT OF AGING AND CHRONIC DISEASE ON USE OF HOSPITAL AND OUTPATIENT SERVICES IN A LARGE HMO - 1971-1991

OBJECTIVES: To examine overall and diagnosis-specific trends in the us e of inpatient and outpatient medical services (1970-1988) among older members of a large HMO. DESIGN: Two cohorts of approximately 3000 per sons aged 65 or older in 1971 and 1980 were compared for hospital and outpatient utilization during 9-year follow-up periods (1971-79 and 19 80-88). All subjects were evaluated for vital status throughout the fo llow up period as well. PARTICIPANTS: All 6057 subjects were members o f the Northern California Kaiser Permanente Medical Care Program in 19 71 or 1980. The study sample was sex-age stratified (65-69,70-79,80+) at baseline. MEASUREMENTS: Data on demographics, outpatient health ser vices utilization, categories of outpatient utilization and disease di agnoses were obtained from membership lists or medical chart review; i npatient utilization, including admitting and discharge diagnosis, len gth of stay, and number of hospital days was assessed from computerize d hospitalization records. RESULTS: Hospital discharge rates (sex-age adjusted) increased by 12% between cohorts, with the largest increases at b the oldest ages. There was a 25% increase among women and a 9% i ncrease among men. Length of stay decreased by 20%. Hospitalization fo r ischemic heart disease decreased by 17%. Congestive heart failure (C HF) discharge rates (sex-age adjusted) were 92% higher in the 1980-88 cohort. For diagnoses related to nursing home institutionalization and frailty, discharge rates were significantly higher in the 1980-88 coh ort: pneumonia (+34%), urinary tract infections (+104%), dehydration ( +110%), osteoarthritis (+64%), syncope (+246%), leg cellulitis (+70%). in-hospital survival improved, but overall percent of readmissions al so increased by 4%; readmissions for CHF increased by 13% and those fo r conditions of frailty by 120%. Overall outpatient visits increased b y 17%. Use of laboratory tests (+57%) and outpatient surgeries (+99%) increased for all age strata in 1980-88 compared with 1971-79. CONCLUS IONS: While overall outpatient and inpatient utilization has largely d ecreased over the past 30 years, as a result of economic factors and i mproved treatments for some major diseases, there has been an increase in utilization among older people. Hospitalization for diagnoses asso ciated with end-stage cardiovascular disease (CHF), musculoskeletal di sease, frailty and iatrogenic aspects of institutionalization are clea rly increasing substantially. The largest impact of aging on health ca re may be the result of institutionalization and its sequelae. Improve d treatment for cardiovascular disease may also be leading to increase d utilization at later stages in the disease process.