Background: Responsiveness, or sensitivity to clinical change, is an important consideration in selection of a health-related quality of life (HRQL) measure for trials or clinical applications. Many approaches can be used to assess responsiveness, which may affect the interpretation of study results. We compared the relative responsiveness of generic and heart failure specific HRQL instruments, as measured both by common psychometric indices and by external clinical criteria.
Methods: We analyzed data collected at baseline and 6-weeks in 298 subjects with heart failure on the following HRQL measures: EQ-5D (US, UK, and VAS Scoring), Kansas City Cardiomyopathy Questionnaire (KCCQ) (Clinical and Overall Summary Score), and RAND12 (Physical and Mental Component Summaries). Three external indicators of clinical change were used to classify subjects as improved, deteriorated, or unchanged: 6-minute walk test, New York Heart Association (NYHA) class, and physician global rating of change. Four responsiveness statistics (T-test, effect size, Guyatt's responsiveness statistic, and standardized response mean) were used to evaluate the responsiveness of the select measures. The median rank of each HRQL measure across responsiveness indices and clinical criteria was then determined.
Results: Average age of subjects was 60 years, 75 percent were male, and had moderate to severe heart failure symptoms. Overall, the KCCQ Summary Scores had the highest relative ranking, irrespective of the responsiveness index or external criterion used. Importantly, we observed that the relative ranking of responsiveness of the generic measures (i.e. EQ-5D, RAND12) was influenced by both the responsive indices and external criterion used.
Conclusion: The disease specific KCCQ was the most responsive HRQL measure assessing change over a 6-week period, although generic measures provide information for which the KCCQ is not suitable. The responsiveness of generic HRQL measures may be affected by the index used, as well as the external criterion to classify patients who have clinically change or remained stable.