Background Patients diagnosed of gout have poorer quality of life (QoL) and higher disability, compared to general population . Several questionnaires and other instruments have been used to assess these features, but not all of them have been fully validated.
Objectives To evaluate the clinimetric properties of the tools used to assess QoL and function in patients with gout.
Methods A systematic literature search was performed in Medline, EMBASE and the Cochrane library from 1950 to October 2011, and the ACR and EULAR abstracts (2010-2011). To be included the studies had to evaluate clinimetric properties (validity, reliability, feasibility or responsiveness) of instruments used to evaluate QoL and function in gout, or to give data from which these may be calculated. Intervention studies were also included in order to estimate responsiveness. Titles and abstracts of the identified references were screened independently by 2 reviewers. Subsequently, included articles were reviewed in detail and the data collected using ad hoc standard forms. A hand search was completed by reviewing the references of the included studies and all the publications or other information provided by experts were examined. Risk of bias was evaluated using the COSMIN checklist for the quality assessment of the HR-PRO instruments .
Results Of the 4,575 references retrieved, 12 studies fulfilled the criteria and were included. Overall risk of bias of these studies was moderate-low. For QoL, SF-36 showed the expected correlation with features of the disease, excellent reliability (Cronbach’s alpha 0.75-0.97, intra-class correlation coefficient (ICC) 0.4-0.9) and was sensitive to change (effect size (ES) 0.91-3.63). Gout Assessment Questionnaire (GAQ) [versions 1.0 and 2.0] showed good reliability (GAQ v2.0: ICC 0.77-0.89, Cronbach’s alpha 0.6-0.94), but moderate responsiveness (ES 0.13-0.68) and weak correlation with SF-36 (GAQv1.0: r 0.02-0.34; GAQv2.0: r -0.1 to -0.43). AIMS and MOS-20 weakly correlated with Health Assessment Questionnaire (HAQ) (0.1-0.6 and -0.1 to -0.5, respectively), with moderate reliability (ICC 0.1-0.7 and 0.27-0.65, respectively), but no study addressed their responsiveness. For function, HAQ correlated with SF-36 (r -0.35 to -0.83) and other indexes, showed good reliability (Cronbach’s alpha 0.91-0.97, ICC 0.76-0.84) and was sensitive to change (ES 0.62-1.4). Other instruments, like hand pressure strength, walking time or a visual analog scale for disability, have been poorly evaluated.
Conclusions SF-36 and HAQ showed good clinimetric properties for the evaluation of QoL and function in patients with gout. The validity of other instruments still needs to be confirmed in further studies.
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Mokkink LB. Qual Life Res 2010; 19(4):539.
Disclosure of Interest None Declared