Prevalence of and factors associated with gabapentinoid use and misuse among Texas Medicaid recipients

Gabapentinoids include drugs such as gabapentin and pregabalin, which are both approved by the FDA for the treatment of neuropathic pain, as well as other conditions. Rising prescribing trends and fatalities due to concurrent opioid overdose have created public health concerns regarding gabapentinoid misuse and abuse in the United States (US). Gabapentin prescriptions in the US increased from approximately 39 million (2012) to 67 million (2018) and pregabalin sales more than doubled from $2 billion (2012) to $4.4 billion (2016). This study aimed to assess the prevalence of and factors associated with gabapentinoid use and misuse. This was a retrospective database study using Texas Medicaid prescription and medical claims from 1/1/12-8/30/16. Subjects were included if they: were between 18–63 years at index date, had at least one gabapentinoid prescription, and were continuously enrolled for 6 months pre-index and 12 months post-index. The dependent variable in this study was gabapentinoid misuse while age, gender, concurrent opioid use, neuropathic pain diagnoses and gabapentinoid type were independent variables. Of included subjects (N=39,000), 0.2% (N=81) were gabapentinoid misusers. The majority (76.4%) of gabapentinoid users were 41–63 years with a mean±SD age of 48.2±10.7 years. Gabapentinoid misusers were significantly younger than gabapentinoid non-misusers (45.1±11.0 vs. 48.2±10.7, p=0.0084). The majority were female (68.1%), and a significantly higher proportion of males misused gabapentinoids compared to females (0.3% vs. 0.2%, p=0.0079). Over one-half (51.9%) of the study sample had neuropathic pain and gabapentinoid misuse was significantly higher in neuropathic pain patients compared to those without neuropathic pain (0.3% vs. 0.1%, p=0.0078). Over three-quarters (77.4%) of patients were using gabapentin, however, gabapentinoid misuse was significantly higher among pregabalin users compared to gabapentin users (0.4% vs. 0.2%, p=0.0003). About one-sixth (17.3%) of gabapentinoid users had at least 90 days of concurrent opioid use. However, there was no significant difference in gabapentinoid misuse among patients with concurrent opioid use compared to patients without (0.3% vs. 0.2%, p = 0.1440). The prevalence of gabapentinoid misuse was low (0.2%) among Texas Medicaid recipients and younger age, male gender, neuropathic pain diagnosis and pregabalin use were significantly associated with gabapentinoid misuse.Pharmaceutical Science