Published norms underestimate the health-related quality of life among persons with type 2 diabetes

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. Study Design and 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. Conclusion: 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.