Responsiveness of patient-based and external rating scales in multiple sclerosis: head-to-head comparison in three clinical settings.

BACKGROUND: Patient-based rating scales and especially quality of life scales have received increasing attention as secondary outcome measures in multiple sclerosis (MS). Responsiveness to health-related change of quality of life scales is thus an important property when these measures are to be used successfully in clinical trials. METHODS: We conducted an analysis of 3 cohorts of MS patients to examine responsiveness of the Hamburg Quality of Life Questionnaire for Multiple Sclerosis (HAQUAMS). One cohort consisted of patients from the outpatient clinic whose overall health status deteriorated over the course of one year (n=53), one study investigated two neurorehabilitation programs (n=20 each) and a third study investigated a low-level aerobic fitness training intervention (n=15). RESULTS: The total score of the HAQUAMS and several subscales was found to be responsive in all three settings. In addition, we provide minimally important difference (MID) estimates based on anchor- and distribution-based methods for all scales of the HAQUAMS. CONCLUSIONS: The HAQUAMS is responsive to change in observational and intervention studies in MS in adequately powered trials.