Development and validation of a patient self-assessed questionnaire on satisfaction with communication of the multiple sclerosis diagnosis

Background: We describe the development and clinical validation of a patient self-administered tool assessing the quality of multiple sclerosis diagnosis disclosure. Method: A multiple sclerosis expert panel generated questionnaire items from the Doctor’s Interpersonal Skills Questionnaire, literature review, and interviews with neurology inpatients. The resulting 19-item Comunicazione medico-paziente nella Sclerosi Multipla (COSM) was pilot tested/debriefed on seven patients with multiple sclerosis and administered to 80 patients newly diagnosed with multiple sclerosis. The resulting revised 20-item version (COSM-R) was debriefed on five patients with multiple sclerosis, field tested/debriefed on multiple sclerosis patients, and field tested on 105 patients newly diagnosed with multiple sclerosis participating in a clinical trial on an information aid. The hypothesized monofactorial structure of COSM-R section 2 was tested on the latter two groups. Results: The questionnaire was well accepted. Scaling assumptions were satisfactory in terms of score distributions, item—total correlations and internal consistency. Factor analysis confirmed section 2’s monofactorial structure, which was also test—retest reliable (intraclass correlation coefficient [ICC] 0.73; 95% CI 0.54—0.85). Section 1 had only fair test—retest reliability (ICC 0.45; 95% CI 0.12—0.69), and three items had 8—21% missed responses. Conclusions: COSM-R is a brief, easy-to-interpret MS-specific questionnaire for use as a health care indicator.