title: Published norms underestimate the health-related quality of life among persons with type 2 diabetes.
abstract: OBJECTIVE
  To assess health-related quality of life (HRQL) among adults with type 2 diabetes using the Short Form (SF)-36 and to obtain pooled estimates of HRQL for subpopulations defined by demographic characteristics, diabetes-related complications, and comorbidities.
  
  
  METHODS
  We conducted computerized searches of multiple electronic bibliographic databases, and studies in any language were selected in which HRQL was reported among adults with type 2 diabetes using the SF-36. Estimates were combined using a random-effects model.
  
  
  RESULTS
  One hundred eighteen studies fulfilled the inclusion criteria. HRQL was lower in persons with type 2 diabetes, as measured by all the eight component scores of the SF-36 when compared with the existing U.S. population norms and with previously published type 2 diabetes norms. SF-36 component and summary scores were extremely heterogeneous, and subpopulation data were sparse; this precluded obtaining meaningful pooled scores for most populations of interest and made comparisons among subpopulations difficult.
  
  
  CONCLUSIONS
  Our data suggest that previously published norms may underestimate the effect of diabetes on HRQL, and diabetes populations are extremely heterogeneous, making broad population "norms" for HRQL in type 2 diabetes of limited use. Additional research with important subpopulations and individual-level data are needed to further explore the effect of diabetes on HRQL.
authors.affiliation: Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, OR 97239, USA. norriss@ohsu.edu
authors.forename: Susan L
authors.initials: SL
authors.lastname: Norris
authors.forename: Tarra K
authors.initials: TK
authors.lastname: McNally
authors.forename: Xuanping
authors.initials: X
authors.lastname: Zhang
authors.forename: Brittany
authors.initials: B
authors.lastname: Burda
authors.forename: Benjamin
authors.initials: B
authors.lastname: Chan
authors.forename: Farah M
authors.initials: FM
authors.lastname: Chowdhury
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Donald
authors.initials: D
authors.lastname: Patrick
mesh_terms: D016206:Databases, Bibliographic; D003924:Diabetes Mellitus, Type 2; D019317:Evidence-Based Medicine; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care / Q000592:standards*; D011788:Quality of Life; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires