Estimates of complications of medical care in the adult US population

BACKGROUND: Total US population estimates of complications of medical care have relied on extrapolations of state-specific estimates. Generalizability is suspect because findings are limited by geographical location or time. We describe the relationship between the annual prevalence of complications of medical care (CM) and socio-demographic characteristics in the adult US population. METHODS: We used data from the National Health Interview Surveys, annual nationwide surveys of the resident, civilian, noninstitutionalized population of the United States. The main outcome of interest was self-reported conditions from CMs (ICD-9 996-999) and activity limitations that arise from such events. Univariate estimates and multivariably adjusted models accounting for selected socio-demographic characteristics and health status were derived. RESULTS: A total of 618,167 reports of conditions from 313,438 subjects 18 years and older from 1987 to 1994 were examined. In 1987, 830,386 adults reported complications of medical care, increasing by about 40% to 1,174,089 adults in 1994. Based on an extrapolation to the US adult population, rates increased by 25% from 558 to 678 per 100,000 during the same period. One-third reported onset a year prior to the interview; two-thirds visited a doctor six months prior; half experienced limitation in major activities; a quarter reported limitation in personal care activities. In the two weeks preceding the interview, complications of medical care caused an average of 1.72 days of restricted activity, 0.79 days spent in bed, and 0.58 days of work lost. Race modified the age-specific risk of these complications. CONCLUSIONS: Complications of medical care impose heavier morbidity than previously considered with some indication that socio-demographic variables modify the risk for injuries.