Sensitivity to change in systemic sclerosis of the McMaster-Toronto Arthritis Patient Preference Disability Questionnaire (MACTAR): shift in patient priorities over time.

OBJECTIVE: To assess the sensitivity to change of the McMaster-Toronto Arthritis Patient Preference Disability Questionnaire (MACTAR) in systemic sclerosis (SSc) and a shift in patient priorities over time.
METHODS: We assessed 49 patients with SSc (8 men) using the MACTAR in a prospective longitudinal study twice or more during annual meetings of the French patient association from 2004 to 2007. Patient-perceived improvement or worsening regarding health status was recorded. Sensitivity to change was assessed by the effect size (ES) and the standardized response mean (SRM) of the MACTAR.
RESULTS: The MACTAR global score was significantly increased at followup in the whole group of patients, and the ES and SRM values were -0.37 and -0.34, respectively. These values were similar to those observed for widely used outcome measures for SSc such as the Health Assessment Questionnaire. As defined by the International Classification of Functioning, Disability and Health, the 3 disability domains most often cited at baseline were mobility (7 activities, cited 17 times; 33.3% of patients), domestic life (4 activities, cited 17 times; 33.3% of patients), and community, social and civic life (3 activities, cited 10 times; 19.6% of patients). At followup, 40 patients had changed their first priority and 34 changed 3 priorities.
CONCLUSION: The evolution in MACTAR global score over time for patients with SSc reflects longterm general feelings of deterioration. However, shifts in patient priorities are common and may influence the sensitivity to change of the instrument.