Association Between Dual Trajectories of Opioid and Gabapentinoid Use and Healthcare Expenditures Among US Medicare Beneficiaries

Cohort study of new off-label gabapentin prescribing in chronic opioid users

INTRODUCTION

Gabapentin is commonly prescribed as an off-label adjunct to opioids because of its safer risk profile. Recent evidence has shown an increased risk of mortality when coprescribed with opioids. Therefore, we aimed to evaluate whether the addition of off-label gabapentin in patients with chronic opioid use is associated with a reduction in opioid dosage.

METHODS

We performed a retrospective cohort study of patients with chronic opioid use with a new off-label gabapentin prescription (2010-2019). Our primary outcome of interest was a reduction in opioid dosage measured via oral morphine equivalents (OME) per day after the addition of a new off-label gabapentin prescription.

RESULTS

In our cohort of 172,607 patients, a new off-label gabapentin prescription was associated with a decrease in opioid dosage in 67,016 patients (38.8%) (median OME/day reduction:13.8), with no change in opioid dosage in 24,468 patients (14.2%), and an increase in opioid dosage in 81,123 patients (47.0%) (median OME/day increase: 14.3). A history of substance/alcohol use disorders was associated with a decrease in opioid dosage after the addition of a new off-label gabapentin (aOR 1.20, 95% CI 1.16 to 1.23). A history of pain disorders was associated with a decrease in opioid dosage after the initiation of a new gabapentin prescription including arthritis (aOR 1.12, 95% CI 1.09 to 1.15), back pain (aOR 1.10, 95% CI 1.07 to 1.12), and other pain conditions (aOR 1.08, 95% CI 1.06 to 1.10).

CONCLUSIONS

In this study of patients with chronic opioid use, an off-label gabapentin prescription did not reduce opioid dosage in the majority of patients. The coprescribing of these medications should be critically evaluated to ensure optimal patient safety.

Polypharmacy and Healthcare Service Use Among Prescription Opioid Poisoning Cases Age 50

Objectives: To examine relationships between polypharmacy and level of healthcare service use among prescription opioid poisoning cases age 50 and older. Methods: Data came from the American Association of Poison Control Center's National Poison Data System, 2015-2020. We used multinomial logistic regression to examine the study questions. Results: Of the 77 946 cases with prescription opioid exposures, 64.5% were managed at a healthcare facility (HCF). Of HCF-managed cases, 41.2% were treated/evaluated and released and 21.3% and 37.5% were admitted for noncritical care and critical care, respectively. Medications for cardiovascular disease, benzodiazepines, other types of sedatives/hypnotics, antipsychotics, muscle relaxants, acetaminophen, and gabapentin were associated with increased risk of admission to both noncritical and critical care compared to treatment/evaluation and release. Acetaminophen use had the highest relative risk ratios (RRRs) for noncritical care (1.70, 95% CI = 1.51-1.91) and critical care (1.56, 95% CI = 1.39-1.76). Each additional medication/substance used was associated with 1.14 (95% CI = 1.11-1.17) and 1.19 (95% CI = 1.16-1.22) greater risk of noncritical and critical care admissions, respectively. Conclusions: Among older-adult poison control center cases for prescription opioid exposures, co-use of several commonly prescribed/used medicines was associated with increased risk of admissions to both noncritical and critical care units. Careful monitoring of medication use among older adults who use prescription opioids may reduce the risk of unintentional and intentional opioid poisoning.

Opioid poisoning cases aged 50+ in the 2015-2020 National Poisoning Data System: suspected suicides versus unintentional poisoning and other intentional misuse/abuse

High rates of opioid overdose and suicide among the 50+ age group call for an examination of suicidal intent in overdose incidents. Using 2015-2020 National Poison Data System opioid poisoning cases aged 50+ (n = 83 153), we examined the types of opioids and other substances associated with suspected suicides compared to intentional misuse/abuse without suicidal intent. During the six years, prescription opioid cases decreased, while illicit opioid cases increased. Among both types of opioid poisoning cases, the proportions of suspected suicides decreased and those of intentional misuse/abuse without suicidal intent increased. However, due to the large increase in illicit opioid cases, the number of suspected suicide cases involving illicit opioids increased. Multivariable analyses showed that among prescription opioids, acetaminophen with opioid (IRR = 1.17, 95% CI = 1.11-1.24) and tramadol (IRR = 1.12, 95% CI = 1.06-1.47) were associated with higher risk of suspected suicides than intentional misuse/abuse without suicidal intent. Among illicit opioid cases, fentanyl poisoning cases were associated with lower risk of suspected suicides (IRR = 0.40, 95% CI = 0.17-0.94). Of other medications, use of benzodiazepines and antipsychotics was consistently associated with higher risk of suspected suicides in both prescription and illicit opioid cases. Alcohol and cocaine were also associated with higher risk of suspected suicide. Along with continued reductions in opioid prescribing, more effective monitoring of individual patient misuse/abuse behaviors and suicide risk assessment are needed. Healthcare professionals should also review other prescription medications frequently co-prescribed with opioids that may have additive effects on suicidal behaviors among older adults.

Exposure reasons, other substance use, and medical outcomes of poison control center cases aged 50+ involving opioids, 2015-2020

CONTEXT

Rates of prescription opioid (PO) prescribing and filling remain high, and illicit opioid (IO) use has increased among late middle-aged and older adults. Research on PO and IO poisoning and their impacts among these age groups is needed.

METHODS

Data came from 2015 to 2020 poison control center cases aged 50+ (N = 83,135). We used χ2 tests to examine changes over the study period in the numbers of PO and IO cases, type of opioids used, exposure reasons, and medical outcomes. We fit multinomial logistic regression models to examine the associations of medical outcomes with exposure reasons and other medication/substance involvement.

RESULTS

Between 2015/2016 and 2020, the numbers and shares of PO-only cases steadily declined, but IO cases, with or without PO, nearly tripled, constituting almost 10% of all PCC opioid cases aged 50+ in 2020. The rates of intentional misuse/abuse increased among both PO-only and IO (with/without PO) cases during the study period, and the death rate among IO cases sharply increased in 2020. Compared to adverse reactions or other unintentional exposures, intentional misuse/abuse and suspected suicides were associated with significantly higher risks of serious outcomes (e.g., risk of death from intentional misuse/abuse: RRR = 22.11, 95% CI = 16.74-29.20 in PO-only cases and RRR = 6.95, 95% CI = 2.37-20.39 in IO cases with/without PO). The use of most other medications and substances was also significantly associated with serious outcomes.

DISCUSSION

Among older adults, medical outcomes in opioid poisoning cases have become more serious in recent years as intentional misuse/abuse became more common. Opioid use disorder treatment should be readily available and accessible, and alternatives to PO prescribing should be considered.

CONCLUSIONS

Among individuals aged 50+, PO poisoning cases decreased, but IO cases increased sharply from 2015 to 2020 with concomitant increases in intentional misuse/abuse and serious medical outcomes.