The development and psychometric evaluation of the Survey of Obstructive Sleep Apnea Functional Health Literacy

Obstructive Sleep Apnea (OSA) is a highly prevalent disorder that disparately affects racial/ethnic minorities. OSA functional health literacy can contribute to health disparities. Documenting poor OSA functional health literacy is needed to inform research agendas, policy, and advocacy efforts. The objective of this study is to develop a scale for measuring OSA functional health literacy among diverse audiences and a variety of reading levels and to ascertain its reliability and validity.

Development of the 18-item Survey of OSA Functional Health Literacy (SOFHL) was guided by literature review and input from experts. A convenience sample of persons enrolled in a clinical trial completed the survey (n=194). The psychometric evaluation was conducted using factor analysis to identify the number of dimensions in the SOFHL and their relationship to other domains that are relevant to OSA functional health literacy.

Internal consistency reliability (alpha) was estimated for the resulting scale and correlations with educational attainment and income completed. All respondents were Black and 29% reported average household income less than $10,000 USD. Confirmatory factor analysis provided support for two dimensions: OSA general knowledge (alpha=0.81) and self-efficacy for OSA self-management (alpha=0.71).

Higher educational attainment and socioeconomic status were associated with better OSA functional health literacy. These results provide preliminary support for the SOFHL, a measure that can be used to assess OSA functional health literacy.