Prolonged use of newly prescribed gabapentin after surgery.

Background: Surgeons have made substantial efforts to decrease postoperative opioid prescribing, largely because it can lead to prolonged use. These efforts include adoption of non-opioid pain medication including gabapentin. Like opioids, gabapentin use may be prolonged, increasing the risk of altered mental status and even overdose and death when taken concurrently with opioids. However, little is known about postoperative prolonged use of gabapentin in older adults.

Methods: We merged a 20% sample of Medicare Carrier, MedPAR and Outpatient Files with Part D for 2013-2018. We included patients >65 years old without prior gabapentinoid use who underwent common non-cataract surgical procedures. We defined new postoperative gabapentin as fills for 7 days before surgery until 7 days after discharge. We excluded patients whose discharge disposition was hospice or death. The primary outcome was prolonged use of gabapentin, defined as a fill>90 days after discharge. To identify risk factors for prolonged use, we constructed logistic regression models, adjusted for procedure and patient characteristics, length of stay, disposition location, and care complexity.

Results: Overall, 17,970 patients (3% of all eligible patients) had a new prescription for gabapentin after surgery. Of these, the mean age was 73 years old and 62% were female. The most common procedures were total knee (45%) and total hip (21%) replacements. Prolonged use occurred in 22%. Those with prolonged use were more likely to be women (64% vs. 61%), be non-White (14% vs. 12%), have concurrent prolonged opioid use (44% vs. 18%), and have undergone emergency surgery (8% vs. 4%). On multivariable analysis, being female, having a higher Charlson comorbidity score, having an opioid prescription at discharge and at >90 days and having a higher care complexity were associated with prolonged use of gabapentin.

Conclusions: More than one-fifth of older adults prescribed gabapentin postoperatively filled a prescription >90 days after discharge, especially among patients with more comorbidities and concurrent prolonged opioid use, increasing the risk of adverse drug events and polypharmacy.