title: SF-6D utility index as measure of minimally important difference in health status change.
abstract: OBJECTIVE
  To combine anchor- and distribution-based approaches to identify minimally important differences (MIDs) for the short-form six-dimension utility index (SF-6D) and to identify variables associated with self-reported health status change.
  
  
  METHODS
  Descriptive, exploratory, nonexperimental study.
  
  
  METHODS
  United States between April 1, 1999, and October 31, 1999.
  
  
  METHODS
  2,317 participants of SADD-Sx (Study of Antihypertensive Drugs and Depressive Symptoms), aged 50 years or older and with hypertension and coronary artery disease.
  
  
  METHODS
  Patients were randomized into a verapamil SR- or atenolol-led hypertensive treatment strategy and mailed baseline and 1-year surveys.
  
  
  METHODS
  SF-6D utility scores for patients completing both surveys.
  
  
  RESULTS
  The pooled mean (±SD) MID change on the SF-6D of patients whose health status minimally changed was 0.035 ± 0.095. The anchor-based change scores had a median value of 0.036 (interquartile range -0.03 to 0.10). One-third and one-half of the SD of SF-6D change scores were 0.035 and 0.053, respectively. Whites were less likely to report minimally improved health status compared with nonwhites (odds ratio 0.59 [95% CI 0.40-0.88]). Change in SF-6D scores improved prediction of health status change.
  
  
  CONCLUSIONS
  We recommend using the MID range based on all patients combined (-0.03 to 0.10) to interpret SF-6D scores. These estimates can be used in conjunction with other measures of efficacy to determine meaningful changes. SF-6D demonstrates potential utility in predicting minimally important improvement or worsening among patients receiving different pharmacologic medications.
authors.affiliation: College of Pharmacy, University of Florida, Gainesville, USA.
authors.forename: Pranav K
authors.initials: PK
authors.lastname: Gandhi
authors.forename: L Douglas
authors.initials: LD
authors.lastname: Ried
authors.forename: Alex
authors.initials: A
authors.lastname: Bibbey
authors.forename: I-Chan
authors.initials: IC
authors.lastname: Huang
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001262:Atenolol / Q000627:therapeutic use*; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D003324:Coronary Artery Disease / Q000503:physiopathology; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D044469:Racial Groups; D014481:United States; D014700:Verapamil / Q000627:therapeutic use*
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D001262:Atenolol; D014700:Verapamil