Cross-Country Differences in Pain Medication Before and After Spinal Cord Stimulation: A Pooled Analysis of Individual Patient Data From Two Prospective Studies in the United Kingdom and Belgium

Abstract

ObjectivesSpinal cord stimulation (SCS) can reduce the need for opioids; however, the influence on the full spectrum of pain medication is less known. The aims of this study were to explore general prescription practices for patients scheduled for SCS, potential differences in prescriptions between Belgium and United Kingdom, and the influence of SCS on pain medication. Materials and MethodsIndividual patient data from the TRIAL-STIM study in the United Kingdom and DISCOVER in Belgium were pooled. Medication use was collected before SCS and three months after SCS from 180 chronic pain patients. The Medication Quantification Scale III (MQS) was used to calculate a total score for medication use, as well as subscores for several classes. Differences in prescription practices between United Kingdom and Belgium were evaluated with two-sided Wilcoxon tests. To evaluate differences in medication use after three months of SCS between United Kingdom and Belgium, Tweedie-generalized linear models were calculated. ResultsThere was a statistically significant difference (−6.40 [95% CI from −3.40 to −9.10]) between the median total MQS score in United Kingdom and Belgium before SCS. Additionally, a significant difference was found for nonsteroidal anti-inflammatory drugs (NSAIDs) (−3.40 [95% CI −3.40 to −6.80]), neuropathic agents (−2.30 [95% CI −0.40 to −3.80]), and benzodiazepines (1.83e−05 [95% CI 2.64−05 to 7.45−05]) between United Kingdom and Belgium, before SCS. Tweedie-generalized models revealed a statistically significant interaction between country and time for MQS, neuropathic agents, and opioids. ConclusionsOur combined analysis revealed differences in prescription practice in patients scheduled for SCS implantation between Belgium and United Kingdom. NSAIDs and neuropathic mood agents are more frequently used in the United Kingdom, presumably due to easier access to repeat prescriptions and over the counter medications. After three months of SCS, a decrease in medication use is observed in both countries, with higher reductions in Belgium, presumably due to strict regulations concerning reimbursement criteria.