A longitudinal analysis of the prescribing patterns of anti–epileptic medicine by using a medicine claims database

Abstract

The prevalence of epilepsy in society is general knowledge; however the impact on social activity as well as other daily factors are not always fully recognised. Epilepsy frequently poses a problem with regard to work–related activities (Heaney, 1999:44). Moran et al. (2004:425) indicated that the major impacts of epilepsy on life were work and school difficulties, driving prohibition, psychological and social life of which restriction of work or schooling has the greatest impact on epileptic’s life. In all cases the type, severity, and frequency of the seizures as well as the age would be relevant. Davis et al. (2008:451) established that 39% of all epileptics were not adherent to their therapy and in patients over 65 this was even higher at 43 %. Non–adherence with antiepileptic medicine appears to be related to increased health care utilisation and costs and may also lead to an increased probable accidents or injuries The general objective was to investigate anti–epileptic medicine prescribing patterns and treatment cost in a section of the private health care sector by using a medicine claims database. A retrospective drug utilisation study was done on the data claims from a pharmacy benefit management company for the study period 1 January 2005 to 31 December 2008. Firstly epilepsy was investigated in order to understand the disease and to determine the prevalence and treatment thereof. It was found that epilepsy is still one of the most common neurological conditions and according to the findings, 2 out of every hundred patients were using anti–epileptic medicine in this section of the private health care sector. To make this condition socially more acceptable and understandable, public education for special target groups concerning the disorder must be conducted as well as employment training programmes for people with epilepsy themselves. The utilisation patterns of anti–epileptic drugs were reviewed, analysed and interpreted. It was determined that anti–epileptic medicine items are relatively expensive with regards to other medicine items on the total database. With regard to gender, more females are using anti–epileptic medicine than males on the database. The largest age group of patients using anti–epileptic medicine, is between > 40 years and <= 64 years of age. It was also clear that prevalence increase as age increase. With regard to the different prescribers, the number of items prescribed by a general practitioner was almost double that of the other prescribers. It was further established that newer anti–epileptic medicines are more expensive than older anti–epileptic medicine according to the cost per tablet in this section of the private health care sector. Carbamazepine and valproate were the two active ingredients that were most frequently prescribed as a single item on a prescription. After a cost–minimisation analysis was done, R134 685.66 could have been saved when generic substitution was implemented. The refill–adherence rate decreased as age increased. Only 30.46% of the trade names was refilled according to acceptable refill–adherence rates. The refill–adherence rate according to active ingredient showed that medicine items containing, phenobarbitone/vit B or gabapentin had the lowest unacceptable refill–adherence rate. The limitations for this study was stipulated and recommendations for further research regarding anti–epileptic medicine were also made.