QS302 - Patterns of Perioperative Gabapentin Use in Older Adults Undergoing Colorectal Surgery

Purpose/Background: Multimodal pain control is the backbone of enhanced recovery pathways (ERP), and gabapentin is included in guidelines to reduce opioid use, but most recommend avoiding use in older adults due to risk of adverse drug events including oversedation, falls, and cognitive dysfunction. Prolonged use beyond the immediate post-operative period may further increase these risks. We hypothesized that, despite recommendations to the contrary, gabapentin is not only being used for perioperative pain control after colorectal surgery in older adults but also may be inappropriately continued well past the postoperative period.

Methods/Interventions: Using a 20% representative sample of Medicare data, merging Medicare Carrier, MedPAR, Outpatient Files with Part D from June 2013- Oct 2018, we identified patients >= 66 years old, gabapentin naïve (ie; no gabapentin for 3-months before surgery), and underwent a colorectal surgical procedure as defined by ICD-10 PCS codes ‘COLO’ and ‘REC’ from National Healthcare Safety Network (NHSN). Patients were excluded if they died < 180 days after surgery or were discharged to skill nursing facilities. Primary outcome was prolonged gabapentin use (refill >90 days after discharge). Logistic regression was used to identify risk factors for prolonged use, and were adjusted for age, gender, race, length of stay, concurrent opioid use, and disposition.

Results/Outcomes: A total of 34,576 patients underwent colorectal surgery and 979 patients (3%) had a new prescription for gabapentin at discharge. Of these patients, 221 (22%) had prolonged use of gabapentin. Interestingly, prolonged gabapentin use was more likely in patients that did not receive a concurrent perioperative prescription of opioids (27.6% vs 17.9%, p < 0.01). In patients that were prescribed opioids, opioid refills beyond the postoperative period were also associated with refills in gabapentin (39.8% vs. 16.1%, p < 0.01). Patients with prolonged gabapentin use had longer lengths of stay (median 6 days, IQR 3-10 vs. 4 days, IQR 3-7, p < 0.01) and increased likelihood of being discharged with home care (p < 0.01) (Table 1). On multivariable analysis, factors associated with prolonged gabapentin use after colorectal surgery include initial prescription of gabapentin without opioids, continued prolonged opioid use beyond the postoperative period, and discharge disposition with home care.

Conclusion/Discussion: Gabapentin use for perioperative pain control after colorectal surgery in older adults is relatively rare, but one in five of those that do receive a new prescription have prolonged use contributing to polypharmacy, a known harm. When patients are prescribed gabapentin alone without opioids, they are more likely to have the medication continued beyond the postoperative period. This may be due to confusion regarding the use of gabapentin for postoperative pain, resulting in unnecessary prescription renewals. While ERP has promoted standardization of colorectal surgery care which has driven improved patient outcomes and value, it is critical to consider the potential harm of unanticipated prolonged gabapentin use in older adults.