METHODS: Cross-sectional study of Malaysian ambulant CWE on antiseizure medication for >1 year. Sixteen SNPs in 8 genes (GC, VDR, CYP2R1, CYP24A1, CYP27B1, CYP27A1, CYP3A4, NADSYN1/DHCR7) were genotyped. Linear and logistic regression models and co-variates adjusted analyses were used. SNPs with significant associations were further analysed in a group of ethnically-matched healthy Malaysian children.
RESULTS: 239 CWE were recruited (52.7% Malay, 24.3% Chinese and 23.0% Indian) with mean serum 25(OH)D of 58.8 nmol/L (SD 25.7). Prevalence of vitamin D deficiency (≤37.5 nmol/L) was 23.0%. Minor allele of GC-rs4588-A was associated with lower serum 25(OH)D in the meta-analysis of both CWE (β -8.11, P = 0.002) and Malaysian healthy children (β -5.08, P < 0.001), while VDR-rs7975232-A was significantly associated with reduced odds of vitamin D deficiency in Malay subgroup of CWE (OR: 0.16; 95% CI: 0.06-0.49; P = 0.001) and this association was not found in the healthy children group.
CONCLUSIONS: Our results suggest that GC-rs4588 is associated with lower serum 25(OH)D concentration in both Malaysian CWE and healthy children, while VDR-rs7975232A is associated with lower risk of vitamin D deficiency in Malaysian CWE of Malay ethnicity. Our findings may assist in the genetic risk stratification of low vitamin D status among CWE.
Method: Potential studies were identified through a systematic search of Scopus, Science Direct, Google Scholar, and PubMed. The keywords used to identify relevant articles were "adherence," "AED," "epilepsy," "non-adherence," and "complementary and alternative medicine." An article was included in the review if the study met the following criteria: 1) conducted in epilepsy patients, 2) conducted in patients aged 18 years and above, 3) conducted in patients prescribed AEDs, and 4) patients' adherence to AEDs.
Results: A total of 3,330 studies were identified and 30 were included in the final analysis. The review found that the AED non-adherence rate reported in the studies was between 25% and 66%. The percentage of CAM use was found to be between 7.5% and 73.3%. The most common reason for inadequate AED therapy and higher dependence on CAM was the patients' belief that epilepsy had a spiritual or psychological cause, rather than primarily being a disease of the brain. Other factors for AED non-adherence were forgetfulness, specific beliefs about medications, depression, uncontrolled recent seizures, and frequent medication dosage.
Conclusion: The review found a high prevalence of CAM use and non-adherence to AEDs among epilepsy patients. However, a limited number of studies have investigated the association between CAM usage and AED adherence. Future studies may wish to explore the influence of CAM use on AED medication adherence.