Validation of the Brief Medication Adherence Scale (BMAS) in Patients with Epilepsy
Abstract number :
2.418
Submission category :
7. Anti-seizure Medications / 7E. Other
Year :
2024
Submission ID :
1148
Source :
www.aesnet.org
Presentation date :
12/8/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Meagan Tsaw, MB BCh BAO, MSc – The University of Hong Kong
Tommy HF Chung, MSc – The University of Hong Kong
Vincent Wong, BPharm, MPhil – Queen Mary Hospital
Adrian Ching-Hei So, MBBS(student) – The University of Hong Kong
Kandace Chan, MBBS(student) – The University of Hong Kong
Margaret Kay Ho, MBBS, MSc – Queen Mary Hospital, The University of Hong Kong
William C.Y. Leung, MBBS(HK, MRCP(UK), FHKCP, FHKAM(Med) – Queen Mary Hospital, University of Hong Kong
Rationale:
Reliable and accessible self-assessment tools are required to bridge collaborative models of care between community and specialist clinics, and to improve medication safety and adherence among patients with epilepsy (PWE). The Brief Medication Adherence Scale (BMAS) is a validated 10-item self-assessment tool for medication adherence, which has been validated among patients with schizophrenia and related disorders. This study aimed to validate the scale among PWE.
Methods:
PWE followed up at a specialty epilepsy clinic on ≥ 1 anti-seizure medication (ASM) for ≥ 3 months were recruited. Patients with dependent medication intake (e.g. severe intellectual disabilities, residing at high-dependency long-term care facilities) were excluded. Demographic and clinical data were obtained from hospital electronic records. BMAS was conducted by 1 post-graduate and 2 medical students face-to-face or by phone interviews. BMAS was repeated after 2 weeks to evaluate for test-retest reliability using Pearson correlation analyses. Clinic charts were reviewed for any physician remarks on ASM compliance issues.
Factorability of BMAS was evaluated using the determinant of the item correlation matrix, Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy, and the Bartlett’s test of sphericity (BTS). The optimal number of factors was determined using the Kaiser criterion and parallel analysis. Principal axis factoring (PAF) with orthogonal rotation was used to assess the underlying factor structure. Construct validity was evaluated by correlating scores of the BMAS with clinical covariates.
Results:
Out of 176 recruited patients, 144 (81.8%) were enrolled with a slight female predominance (51.4%). Mean time from epilepsy diagnosis was at 197.34 ± 175.05 months, with 35 (24.3%) diagnosed with drug-resistant epilepsy. Most subjects (55.6%) were on 1 ASM, 30.6% on 2, 9.7% on 3, 3.5% on 4, and 0.7% on 5 ASMs. Poor ASM compliance was remarked in 23 patients (16.0%) at clinic visit.
BMAS has no concerns of factorability (det: 0.0462, KMO: 0.73, BTS: χ2(45) =426.80, p< .001). Both the Kaiser criterion and parallel analysis supported a two-factor solution. Based on a cutoff of 0.35 for standardized loading, PAF with varimax rotation showed that items 1 to 5 loaded on one factor could be surmised as medication taking attitudes, while item 6 to 10 could be labeled as medication adherence behaviors. The total variance explained was 42.3% (medication adherence behaviors: 22.4%, medication taking attitudes: 19.9%).
BMAS showed acceptable reliability with Cronbach’s alpha of 0.76. A higher score was associated with fewer physician-remarked compliance issues (r=-0.236, p=.006). Higher BMAS scores were positively correlated with age (r =.306, p< .001), and was negatively associated with the number of ASM prescribed (r=-0.180, p=.038). Good test-retest reliability was demonstrated in a 2-week interval (r(90)=0.715, 95% CI 0.598 – 0.803, t=9.71, p< .001).
Conclusions:
BMAS is a valid and reliable tool for assessing ASM adherence among PWEs outside specialty clinics. Future large-scale studies in community settings may further demonstrate its utility in collaborative models of care.
Funding:
No funding was received.
Anti-seizure Medications