title: Development of a brief measure to assess quality of life in obesity. Comparisons of Five Health Status Instruments for Orthopedic Evaluation Effect Sizes for Interpreting Changes in Health Status
abstract: OBJECTIVE Obesity research ers have a growing interest in measuring the impact of weight and weight reduction on quality of life . The Impact of Weight on  Quality of Life question naire ( IWQOL ) was the first self-report instrument specifically developed to assess the effect of obesity on quality of life . Although the IWQOL has demonstrated excellent psychometric properties , its length ( 74 items ) makes it somewhat cumbersome as an outcome measure in clinical research . This report describes the development of a 31-item version of the IWQOL ( IWQOL-Lite ) . RESEARCH METHODS AND PROCEDURES IWQOLs from 996 obese patients and controls were used to develop the IWQOL-Lite . Psychometric properties of the IWQOL-Lite were examined in a separate cross-validation sample of 991 patients and controls . RESULTS Confirmatory factor analysis provided strong support for the adequacy of the scale structure . The five identified scales of the IWQOL-Lite  ( Physical Function , Self-Esteem , Sexual Life , Public Distress , and Work ) and the total IWQOL-Lite score demonstrated excellent psychometric properties . The reliability of the IWQOL-Lite scales ranged from 0.90 to 0.94 and was 0.96 for the total score . Correlations between the IWQOL-Lite and collateral measures supported the construct validity of the IWQOL-Lite . Changes in  IWQOL-Lite scales over time correlated significantly with changes in weight , supporting its sensitivity to change . Significant differences in IWQOL-Lite scale and total scores were found among groups differing in body mass index , supporting the utility of the IWQOL-Lite across the body mass index spectrum . DISCUSSION The IWQOL-Lite appears to be a psychometrically sound and clinical ly sensitive brief measure of quality of life in obese persons This study represents a long-term effort to find optimal techniques for evaluating outcome in patients who have undergone total joint arthroplasty . Sensitivity of five health status question naires was studied in a longitudinal evaluation of orthopedic surgery . The question naires ( Arthritis Impact Measurement Scales [ AIMS ] , Functional Status Index [ FSI ] ,  Health  Assessment  Question naire [ HAQ ] , Index of  Well  Being [ IWB ] , and Sickness Impact Profile  [ SIP ] ) were administered to 38 patients with end-stage arthritis at three points in time : two weeks before hip or knee arthroplasty , and at three-month and 12- to 15-month follow-up . Response values ( i.e. , changes within patients ) were calculated on four scales : global health , pain , mobility , and social function . By the three-month follow-up , most instruments detected large mean responses in global health , pain scores , and mobility . Smaller changes on these scales were found between three and 12 to 15 months . Social function showed small to modest gains at successive follow-ups . St and ardized response means were calculated to assess sensitivity to detect change . Confidence intervals for these indices were constructed using a jackknife procedure , and significance tests were performed by pairing selected indices . Finally , the study projected sample sizes required to assess a new therapy , using each response . These statistical tools facilitated comparisons among instruments and may prove useful in other setting Health status measures are being used with increasing frequency in clinical research . Up to now the emphasis has been on the reliability and validity of these measures . Less attention has been given to the sensitivity of these measures for detecting clinical change . As health status measures are applied more frequently in the clinical setting , we need a useful way to estimate and communicate whether particular changes in health status are clinical ly relevant . This report considers effect sizes as a useful way to interpret changes in health status . Effect sizes are defined as the mean change found in a variable divided by the st and ard deviation of that variable . Effect sizes are used to translate “ the before and after changes ” in a “ one group ” situation into a st and ard unit of measurement that will provide a clearer underst and ing of health status results . The utility of effect sizes is demonstrated from four different perspectives using three health status data sets derived from arthritis population s administered the Arthritis Impact Measurement Scales ( AIMS ) . The first perspective shows how general and instrument-specific benchmarks can be developed and how they can be used to translate the meaning of clinical change . The second perspective shows how effect sizes can be used to compare traditional clinical measures with health status measures in a st and ard clinical drug trial . The third application demonstrates the use of effect sizes when comparing two drugs tested in separate drug trials and shows how they can facilitate this type of comparison . Finally , our health status results show how effect sizes can supplement st and ard statistical testing to give a more complete and clinical ly relevant picture of health status change . We conclude that effect sizes are an important tool that will facilitate the use and interpretation of health status measures in clinical research in arthritis and other chronic diseases
target: Conclusions The BODY-Q provides a set of independently functioning scales that measure issues important to patients who undergo weight loss .
  BODY-Q scales were responsive to measuring clinical change associated with weight loss 2 years after bariatric surgery
background: Background Recent systematic review s have identified that current patient-reported outcome instruments have content limitations when used to measure change following bariatric surgery .
  The aim of this study was to measure change after bariatric surgery using the BODY-Q , a PRO instrument design ed for weight loss and body contouring .