The short medication adherence scale (SMAS-7): Development and psychometric validation in a general population sample

Area of Science:

• Psychometrics
• Health Services Research
• Behavioral Science

Background:

• Medication adherence is critical for effective treatment outcomes in various health conditions.
• Validated tools for measuring medication adherence are limited in scope and application.
• The need for a concise, multidimensional adherence measure is significant.

Purpose of the Study:

• To develop and validate the Short Medication Adherence Scale (SMAS-7).
• To assess medication adherence levels and identify associated factors in the Lebanese adult population.

Main Methods:

• A cross-sectional study involving 501 Lebanese adults aged 18 years and above.
• Development of the 7-item SMAS-7 from the LMAS-14, administered electronically.
• Psychometric evaluation including exploratory/confirmatory factor analyses, reliability (Cronbach's α, McDonald's ω, ICC), and validity (construct, criterion).

Main Results:

• The SMAS-7 exhibited a robust 3-factor structure (psychological, economic, behavioral) with excellent model fit.
• High internal consistency (α=0.889, ω=0.945) and test-retest reliability (ICC=0.779) were demonstrated.
• Suboptimal adherence was prevalent (52.3%), with gender, region, financial well-being, chronic illness, communication barriers, and patient perception identified as significant predictors.

Conclusions:

• The SMAS-7 shows strong preliminary psychometric properties for measuring medication adherence.
• The scale is a valuable tool for monitoring adherence and informing interventions.
• Further validation in diverse populations is recommended to confirm generalizability.