[Development and initial validation of an instrument to measure the lifestyles of type 2 diabetes mellitus patients 2]

Abstract

Objective: To develop and validate a specific instrument to measure lifestyle of type 2 diabetes mellitus (DM2) patients.

Material and methods: A longitudinal, observational, prospective study was conducted between March 2001 and April 2002 at family medicine healthcare units of the Instituto Mexicano del Seguro Social (Mexican Institute of Social Security (MISS)) in Mexico State's East District. A self-administered instrument (instrument to measure diabetic lifestyles, IMEVID) was designed to measure the lifestyles of diabetic patients. It was submitted for review by a multidisciplinary group of experts who assessed its logical and content validity to measure the lifestyle in DM2 patients. The instrument was administered on two different days to 412 adult subjects with DM2. Some items were excluded on the basis of the frequency with which their answer choices were selected, as well as the item-total correlation, and the item's significant loads in several domains in factorial analysis.

Results: The sample population consisted of 389 (94.7% response) subjects who completed the study. Intraclass correlation coefficients for logical and content validity were 0.91 and 0.95 respectively. After depuration of items, the instrument had 25 closed items grouped in 7 domains: nutrition, physical activity, tobacco consumption, alcohol consumption, information on diabetes, emotions, and therapeutic adherence. The global rating of the questionnaire had a Cronbach's alpha of 0.81 and a test-retest correlation coefficient of 0.84.

Conclusions: The specific questionnaire IMEVID is the first to measure the lifestyle in subjects with DM2. It has logical validity, content validity, and a good level of consistency.