PIC1 Markov Chain Estimation of Life Expectancy of HIV-Infected Patients: Comparison of Two Treatment Alternatives

In RA clinical trials, functional status is increasingly being used as an outcome measure. While it is rather simple to determine the statistical significance of changes, placing the magnitude of these changes into a clinically meaningful context has not been well documented. MIC is "the smallest difference in score, which patients perceive as beneficial and which would mandate, in the absence of troublesome side-effects and excessive cost, a change in the patient's management" Jaeschke et al. 1989].
OBJECTIVE: To determine the MIC in functional status, as measured by the Modified Health Assessment Questionnaire (MHAQ).
METHODS: Data from 123 patients were obtained from a randomized clinical trial of a new RA therapy. Outcomes were MHAQ and patient global assessment, measured at baseline and after 4 weeks of treatment. Eight scale items of MHAQ were summed to obtain a total score ranging from 0 to 24. MIC was determined based on unit changes in patient globals. The accompanying change in MHAQ was calculated. Similar analysis was conducted with physician global assessment for comparative purposes.
RESULTS: Changes of 1, 2, and 3 points in patient globals were accompanied by changes of 2.11, 4.14, and 8.4 points in MHAQ. Changes in MHAQ corresponding to patient globals were proportionate, but similar results were not obtained for the physician global.
CONCLUSION: Inconsistencies in patient and physician assessments stress the continued need for including both perspectives in assessments of new RA therapies. For the overall MHAQ score, the MIC was approximately 2. These results should increase the ability to interpret results using MHAQ.