Development and validation of the parental inhaled medication literacy scale for school-age children with asthma (PIMLS-SA)

Objective This study aims to develop the Parental Inhaled Medication Literacy Scale for School-Aged Children with Asthma (PIMLS-SA) and to evaluate its reliability and validity.Methods From December 2024 to March 2025, 450 parents of school-age children with asthma were recruited from a tertiary children’s hospital in Chongqing to evaluate the reliability and validity of the instrument. The participants were aged 28–69 years (39.37 ± 5.44). Data were collected using a general information form and the PIMLS-SA scale. The scale was developed based on the concept of medication literacy and the Knowledge–Attitude–Practice (KAP) model, and its initial draft was informed by a literature review, Delphi expert consultation, and a pretest. Content validity was determined through consultation with 15 experts in respiratory medicine, pediatric nursing, pharmacy, and research methodology. Data analyses included correlation analysis and Cronbach’s α coefficient to evaluate reliability, and both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to examine construct validity.Results The Parental Inhaled Medication Literacy Scale for School-Aged Children with Asthma (PIMLS-SA) was confirmed to be composed of four domains and eight factors, encompassing a total of 32 items. Specifically, the knowledge domain included 11 items, the medication beliefs domain had 4 items, the skill domain involved 5 items, and the practice domain included 12 items. The results showed that the Cronbach’s α coefficient of PIMLS-SA was 0.856, and for each domain ranged from 0.732 to 0.878; the split-half reliability coefficient of PIMLS-SA was 0.751, and for each domain ranged from 0.613 to 0.822. In evaluating validity, the content validity index (CVI) for individual items ranged from 0.87 to 1.00, and the scale-level content validity index (S-CVI) was 0.94. The correlations between domains and the total scale ranged from 0.451 to 0.778, and inter-domain correlations ranged from 0.148 to 0.398 (p < 0.05). Confirmatory factor analysis results showed that the model fitted well (χ2/df = 2.136, RMSEA = 0.071, SRMR = 0.021, CFI = 0.923, GFI = 0.952, AGFI = 0.943, NFI = 0.951, TLI = 0.855). The convergent validity and discriminant validity were both good.Conclusions The scale has acceptable content validity, construct validity, and good reliability. It can be used to evaluate the level of inhaled medication literacy among parents of school-aged children with asthma in China.