title: Non-response bias and hazardous alcohol use in relation to previous alcohol-related hospitalization: comparing survey responses with population data.
abstract: BACKGROUND
  This study examines whether alcohol-related hospitalization predicts survey non-response, and evaluates whether this missing data result in biased estimates of the prevalence of hazardous alcohol use and abstinence.
  
  
  METHODS
  Registry data on alcohol-related hospitalizations during the preceding ten years were linked to two representative surveys. Population data corresponding to the surveys were derived from the Stockholm County registry. The alcohol-related hospitalization rates for survey responders were compared with the population data, and corresponding rates for non-responders were based on the differences between the two estimates. The proportions with hazardous alcohol use and abstinence were calculated separately for previously hospitalized and non-hospitalized responders, and non-responders were assumed to be similar to responders in this respect.
  
  
  RESULTS
  Persons with previous alcohol-related admissions were more likely currently to abstain from alcohol (RR=1.58, p<.001) or to have hazardous alcohol use (RR=2.06, p<.001). Alternatively, they were more than twice as likely to have become non-responders. Adjusting for this skewed non-response, i.e., the underrepresentation of hazardous users and abstainers among the hospitalized, made little difference to the estimated rates of hazardous use and abstinence in total. During the ten-year period 1.7% of the population were hospitalized.
  
  
  CONCLUSIONS
  Few people receive alcohol-related hospital care and it remains unclear whether this group's underrepresentation in surveys is generalizable to other groups, such as hazardous users. While people with severe alcohol problems--i.e. a history of alcohol-related hospitalizations--are less likely to respond to population surveys, this particular bias is not likely to alter prevalence estimates of hazardous use.
authors.affiliation: Centre for Epidemiology and Community Medicine, Health Care Services, Stockholm County Council, Box 1497, Solna, 171 29, Sweden. Kozma.Ahacic@ki.se
authors.forename: Kozma
authors.initials: K
authors.lastname: Ahacic
authors.forename: Ingemar
authors.initials: I
authors.lastname: Kåreholt
authors.forename: Asgeir R
authors.initials: AR
authors.lastname: Helgason
authors.forename: Peter
authors.initials: P
authors.lastname: Allebeck
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000523:psychology; D019973:Alcohol-Related Disorders / Q000453:epidemiology* / Q000523:psychology; D015982:Bias; D005260:Female; D006306:Health Surveys; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010358:Patient Participation / Q000523:psychology / Q000706:statistics & numerical data*; D011153:Population; D015995:Prevalence; D012042:Registries; D013548:Sweden / Q000453:epidemiology