Assessment of Serum Calcium, Total Alkaline Phosphatase, Vitamin D Levels, and Quality of Life in Patients on Prolonged Antiepileptic Therapy: A Cross-Sectional Study.

Introduction Epilepsy often requires prolonged use of antiepileptic drugs (AEDs), particularly enzyme-inducing agents, which are associated with disturbances in bone metabolism and a decline in quality of life (QoL). These drugs may alter serum calcium, vitamin D, alkaline phosphatase (ALP), and parathyroid hormone (PTH) levels, predisposing patients to osteopenia, osteoporosis, and fractures. The objective of this study was to evaluate the impact of prolonged AED therapy on biochemical markers of bone metabolism and patient-reported QoL using the Quality of Life in Epilepsy Inventory‑31 (QOLIE-31) and to compare these outcomes between patients receiving monotherapy and polytherapy. Methodology This hospital-based cross-sectional observational study was conducted in the Department of General Medicine, Sree Balaji Medical College and Hospital, Chennai, from July 2023 to December 2024. A total of 120 adult epilepsy patients aged 18-65 years who had been on AED therapy for at least one year were recruited by convenience sampling. Patients with comorbid conditions affecting bone health or on calcium/vitamin D supplementation were excluded. Serum calcium, vitamin D, ALP, and PTH were measured to assess bone metabolism. QoL was evaluated using the validated QOLIE-31 questionnaire, with domain scores transformed to a 0-100 scale (higher scores = better QoL). Data were analyzed using IBM SPSS Statistics software, version 25.0 (IBM Corp., Armonk, NY). Continuous variables were expressed as mean ± SD, categorical variables as frequencies/percentages, and comparisons between monotherapy and polytherapy groups were performed using t-tests/chi-square as appropriate. Logistic regression was applied to identify independent predictors of reduced bone density, with p < 0.05 considered statistically significant. Results Among patients on monotherapy, 30 (41.7%) had normal bone mineral density (BMD), 28 (38.9%) had osteopenia, and 14 (19.4%) had osteoporosis. In the polytherapy group, 13 (27.1%) had normal BMD, 25 (52.1%) had osteopenia, and 23 (20.8%) had osteoporosis. Patients on polytherapy had significantly lower calcium and vitamin D levels, higher ALP and PTH, and poorer QoL scores compared with monotherapy. Reduced BMD was more common in the polytherapy group. In multivariable logistic regression, female gender, obesity, alcohol use, hypocalcemia, vitamin D deficiency, elevated ALP, polytherapy, and longer treatment duration were independent predictors of low BMD. Full effect sizes with 95% confidence intervals (CIs) are detailed in the Results section. Conclusion In conclusion, prolonged AED therapy, particularly when involving multiple agents, exerts a detrimental effect on both bone health and overall quality of life in epilepsy patients. These findings highlight the need for regular biochemical monitoring, timely supplementation with calcium and vitamin D, lifestyle modifications such as physical activity and avoidance of alcohol, and careful tailoring of AED regimens to minimize adverse outcomes while maintaining seizure control.