title: An epidemiologic study of episodes of back pain care.
abstract: METHODS
  This was a prospective community-based, observational design.
  
  
  OBJECTIVE
  To describe the epidemiology and risk/prognostic factors for back pain episodes of care in a population representing the nonelderly in the United States.
  
  
  BACKGROUND
  Previous United States studies of the epidemiology of back pain care have used defined industrial populations or have relied on the patient's recall of symptoms and care.
  
  
  METHODS
  Claims forms from the RAND Health Insurance Experiment, a randomized controlled trial of the use of health services, were analyzed. Claims forms were selected if one of the patient-designated reasons for the visit was back pain. Visits were grouped into episodes of care. Descriptive statistics were calculated for episodes. Multivariate logistic regression was used to calculate adjusted odds ratios for independent explanatory sociodemographic and health status variables associated with back pain episodes of care.
  
  
  RESULTS
  The 3105 adults in the Health Insurance Experiment had a combined 11,171 person-years of exposure. Six-hundred-eighty-six persons (22%) had a total 1020 episodes of back pain care, representing 8825 visits. Seventy-one percent of persons had a single episode during the Health Insurance Experiment, and 40% of these episodes consisted of a single visit. There were 9.1 episodes per 100 person-years. Insurance status, geographic site, white race, lesser education, poorer physical functioning, and greater pain at base-line all were independently associated with having a back pain episode of care.
  
  
  CONCLUSIONS
  Back pain episodes of care occur commonly in the adult U.S. population, but usually are brief and recur infrequently.
mesh_terms: D000328:Adult; D000368:Aged; D001416:Back Pain / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy*; D017050:Episode of Care; D005260:Female; D006282:Health Personnel; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors