Measurement properties and comparative performance of health literacy screening questions in a predominantly low income African American population with diabetes

Abstract

ObjectiveTo examine the measurement properties of the 16 screening questions (16-SQ) of inadequate health literacy (HL) and their briefer version (3-SQ), and identify the best screen for inadequate HL in non-white populations. MethodsSample included 378 individuals with type-2 diabetes. We computed sensitivity, specificity, positive and negative likelihood ratios, and C-indices, using the s-TOFHLA as a reference measure. We also conducted exploratory factor analysis, and used structural equation modeling (SEM) for confirmatory purposes. ResultsMean age was 56.1 years, 69% were female, and 83% were African–American. 10% had limited HL (s-TOHFLA scores <23). Six questions (6-SQ) were identified and included in the final item-reduced factor analysis, which showed good fit in confirmatory SEM (chi-square=9.5; P=0.305; RMSEA=0.023). Weighted summative score of the 6-SQ and the item “difficulty understanding written information” performed better than the 3-SQ in identifying patients with inadequate HL (C-indices 0.67 versus 0.75). ConclusionThe weighted summative score of the 6-SQ and the item “difficulty understanding written information” performed better than the other items or combinations of these items in identifying individuals with inadequate HL. Practice implicationsThe proposed weighting of scores could be applied in studies using these screening questions for better classification of inadequate HL.