Prescription Opioid Dose After Vaginal Delivery and the Risk of Serious Opioid-Related Events: A Retrospective Cohort Study

The impact of different strategies for modeling associations between medications at low doses and health outcomes: a simulation study and practical application to postpartum opioid use

Pharmacoepidemiologic studies commonly examine the association between drug dose and adverse health outcomes. In situations where no safe dose exists, the choice of modeling strategy can lead to identification of an apparent safe low dose range in the presence of a nonlinear relationship or due to the modeling strategy forcing a linear relationship through a dose of 0. We conducted a simulation study to assess the performance of several regression approaches to model the drug dose-response curve at low doses in a setting where no safe range exists, including the use of a (1) linear dose term, (2) categorical dose term, and (3) natural cubic spline terms. Additionally, we introduce and apply an expansion of prior work related to modeling dose-response curves at low and infrequently used doses in the setting of no safe dose ("spike-at-zero" and "slab-and-spline"). Furthermore, we demonstrate and empirically assess the use of these regression strategies in a practical scenario examining the association between the dose of the initial postpartum opioid prescribed after vaginal delivery and the subsequent total dose of opioids prescribed in the entire postpartum period among a cohort of opioid-naive women with a vaginal delivery enrolled in Tennessee's Medicaid program (United States, 2007-2014).

Opioid analgesic and antidepressant use during pregnancy and the risk of spontaneous preterm birth: A nested case-control study

BACKGROUND

Given the high prevalence of both mental health and acute pain conditions during pregnancy, use of antidepressants and analgesic opioids in this period is widespread. Whether single and combined use of these medications is associated with spontaneous preterm birth (sPTB) remains unclear.

OBJECTIVES

To investigate the association between maternal prescription opioid and antidepressant medication exposures for co-occurring mental health and acute pain management, either alone or in combination, and sPTB.

METHODS

We used Tennessee Medicaid data (2007-2019) linked to birth certificates to conduct a nested case-control study among 15- to 44-year-old pregnant patients with singleton live births. Cases were identified as spontaneous live births between 24 and <37 gestational weeks using a validated birth certificate-based algorithm. We selected up to 10 controls per case, matched on estimated pregnancy start date and other factors. We identified analgesic opioid and antidepressant pharmacy fills to define medication exposures in the 60 days before index date (case delivery date) and categorised them as unexposed, opioid-only, antidepressant-only and combined exposure. We estimated odds ratios (OR) and 95% confidence intervals (CI) using conditional logistic regression, adjusting for confounders. We assessed the additive interaction between opioids and antidepressants by estimating relative excess risk due to interaction.

RESULTS

We identified 25,406 eligible cases of sPTB and 225,771 matched controls. Opioid-only and combined exposures were associated with higher odds of sPTB relative to unexposed (adjusted OR 1.29, 95% CI 1.23, 1.35 and 1.22, 95% CI 1.06, 1.40, respectively), while antidepressant-only exposure was not (1.04, 95% CI 0.96, 1.12). No additive interaction was identified for combined exposure.

CONCLUSIONS

Exposure to prescription opioids during pregnancy, but not antidepressants, was associated with increased relative odds of sPTB. Co-exposure to opioids and antidepressants did not elevate the odds of sPTB above what we observed for opioid-only exposure.

Changes in Postpartum Opioid Prescribing After Implementation of State Opioid Prescribing Limits

Importance

In response to the growing opioid crisis, states implemented opioid prescribing limits to reduce exposure to opioid analgesics. Research in other clinical contexts has found that these limits are relatively ineffective at changing opioid analgesic prescribing.

Objective

To examine the association of state-level opioid prescribing limits with opioid prescribing within the 30-day postpartum period, as disaggregated by type of delivery (vaginal vs cesarean) and opioid naivete.

Design, Setting, and Participants

This retrospective, observational cohort study used commercial claims data from January 1, 2014, to December 31, 2021, from 49 US states and a difference-in-differences staggered adoption estimator to examine changes in postpartum opioid prescribing among all deliveries to enrollees between the ages of 18 and 44 years in the US.

Exposures

The implementation of a state opioid prescribing limit between 2017 and 2019.

Main Outcomes and Measurements

The primary outcomes for this analysis were the number of prescriptions for opioid analgesics, proportion of prescriptions with a supply greater than 7 days, and milligrams of morphine equivalent (MMEs) per delivery between 3 days before and 30 days after delivery.

Results

A total of 1 572 338 deliveries (enrollee mean [SD] age, 30.20 [1.59] years) were identified between 2014 and 2021, with 32.3% coded as cesarean deliveries. A total of 98.4% of these were to opioid-naive patients. The mean MMEs per delivery was 310.79, with higher rates in earlier years, states that had an opioid prescribing limit, and cesarean deliveries. In a covariate-adjusted difference-in-differences regression analysis, opioid prescribing limits were associated with a decrease of 148.70 MMEs per delivery (95% CI, -657.97 to 360.57) compared with states without such limits. However, these changes were not statistically significant. The pattern of results was similar among other opioid-prescribing outcomes and types of deliveries.

Conclusions and Relevance

The results of this cohort study suggest that opioid prescribing limits are not associated with changes in postpartum opioid prescribing regardless of delivery type or opioid naivete, which is consistent with research findings on these limits in other conditions or settings. Future research could explore what kinds of prevention mechanisms reduce the risk of opioid prescribing during pregnancy and postpartum.

Opioid and non-opioid analgesic regimens after fracture and risk of serious opioid-related events

Background

Non-opioid analgesics are prescribed in combination with opioids among patients with long bone fracture to reduce opioid prescribing needs, yet evidence is limited on whether they reduce the risk of serious opioid-related events (SOREs). We compared the risk of SOREs among hospitalized patients with long bone fracture discharged with filled opioid prescriptions, with and without non-opioid analgesics.

Design

We identified a retrospective cohort of analgesic-naïve adult patients with a long bone fracture hospitalization using the Merative MarketScan Commercial Database (2013-2020). The exposure was opioid and non-opioid analgesic (gabapentinoids, muscle relaxants, non-steroidal anti-inflammatory drugs, acetaminophen) prescriptions filled in the 3 days before through 42 days after discharge. The outcome was the development of new persistent opioid use or opioid use disorder during follow-up (day 43 through day 408 after discharge). We used Cox proportional hazards regression with inverse probability of treatment weighting with overlap trimming to compare outcomes among those that filled an opioid and a non-opioid analgesic to those that filled only an opioid analgesic. In secondary analyses, we used separate models to compare those that filled a prescription for each specific non-opioid analgesic type with opioids to those that filled only opioids.

Results

Of 29 489 patients, most filled an opioid prescription alone (58.4%) or an opioid and non-opioid (22.0%). In the weighted proportional hazards regression model accounting for relevant covariates and total MME, filling both a non-opioid analgesic and an opioid analgesic was associated with 1.63 times increased risk of SOREs compared with filling an opioid analgesic only (95% CI 1.41 to 1.89). Filling a gabapentin prescription in combination with an opioid was associated with an increased risk of SOREs compared with those that filled an opioid only (adjusted HR: 1.84 (95% CI1.48 to 2.27)).

Conclusions

Filling a non-opioid analgesic in combination with an opioid was associated with an increased risk of SOREs after long bone fracture.

Level of evidence

Level III, prognostic/epidemiological.

Study type

Retrospective cohort study.

Nonsteroidal anti-inflammatory drug "allergy" labeling is associated with increased postpartum opioid utilization

BACKGROUND

Current guidelines recommend a stepwise approach to postpartum pain management, beginning with acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs), with opioids added only if needed. Report of a prior NSAID-induced adverse drug reaction (ADR) may preclude use of first-line analgesics, despite evidence that many patients with this allergy label may safely tolerate NSAIDs.

OBJECTIVE

We assessed the association between reported NSAID ADRs and postpartum opioid utilization.

METHODS

We performed a retrospective cohort study of birthing people who delivered within an integrated health system (January 1, 2017, to December 31, 2020). Study outcomes were postpartum inpatient opioid administrations and opioid prescriptions at discharge. Statistical analysis was performed on a propensity score-matched sample, which was generated with the goal of matching to the covariate distributions from individuals with NSAID ADRs.

RESULTS

Of 38,927 eligible participants, there were 883 (2.3%) with an NSAID ADR. Among individuals with reported NSAID ADRs, 49.5% received inpatient opioids in the postpartum period, compared to 34.5% of those with no NSAID ADRs (difference = 15.0%, 95% confidence interval 11.4-18.6%). For patients who received postpartum inpatient opioids, those with NSAID ADRs received a higher total cumulative dose between delivery and hospital discharge (median 30.0 vs 22.5 morphine milligram equivalents [MME] for vaginal deliveries; median 104.4 vs 75.0 MME for cesarean deliveries). The overall proportion of patients receiving an opioid prescription at the time of hospital discharge was higher for patients with NSAID ADRs compared to patients with no NSAID ADRs (39.3% vs 27.2%; difference = 12.1%, 95% confidence interval 8.6-15.6%).

CONCLUSION

Patients with reported NSAID ADRs had higher postpartum inpatient opioid utilization and more frequently received opioid prescriptions at hospital discharge compared to those without NSAID ADRs, regardless of mode of delivery.

Endogenous opiates and behavior: 2021

This paper is the forty-fourth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2021 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonizts and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

The immediate and long-term effects of prenatal opioid exposure

The opioid epidemic has adversely affected neonates and children, yet the mechanisms by which it impacts this population are not well understood. Not only does prenatal opioid exposure result in short-term consequences shortly after birth, it also creates long-term sequelae that may predispose these children to physical, emotional, psychiatric, cognitive, and socioeconomic problems in the future. This article provides a scoping overview of the long-term effects of antenatal opioid exposure on neonates and children as well as quality improvement and research efforts to understand and mitigate this major public health concern.

The risk of serious opioid-related events associated with common opioid prescribing regimens in the postpartum period after cesarean delivery

BACKGROUND

Opioid analgesics are commonly prescribed to women after cesarean delivery. There is a growing effort to prescribe opioids judiciously; however, the risk of serious opioid-related events associated with specific prescribing patterns after cesarean delivery remains unclear.

OBJECTIVE

We examined the association between the dosage of the first opioid prescription filled after cesarean delivery and the risk of serious opioid-related events.

STUDY DESIGN

We identified opioid-naïve women with a cesarean delivery enrolled in Tennessee Medicaid (2007-2014). Pharmacy prescription fill data characterized opioids filled within 5 days after delivery. Patients were followed up from day 5 after delivery to the earliest of the following: serious opioid-related event (persistent opioid use, evidence of opioid use disorder [diagnosis or methadone or buprenorphine fill], overdose, or opioid-related death), non-opioid-related death, enrollment loss, or 365th day. We estimated the adjusted hazard ratios and 95% confidence intervals for the serious opioid-related event outcomes based on the dosage (morphine milligram equivalents) of the first filled opioid prescription, adjusting for baseline sociodemographic characteristics, delivery complications, multiple deliveries, comorbidities, and medication use. Secondary analyses examined the role of commonly prescribed opioid strengths and quantities.

RESULTS

The overall incidence rate of serious opioid-related events among women after cesarean delivery was 3.0 per 100 person-years. Compared with women who did not fill an opioid prescription, the rate of serious opioid-related events was higher among women who filled an opioid prescription, although only significantly higher among women who filled a total dosage of ≥100 morphine milligram equivalents (97.1% of opioid prescriptions). In the secondary analyses, women with a low prescribed daily opioid dosage and women with a low prescribed number of oxycodone (5 mg) tablets (<10 tablets) were not at increased risk of serious opioid-related events compared with women who did not fill an opioid prescription.

CONCLUSION

Opioid-naïve women who filled a postpartum opioid prescription at commonly prescribed doses after cesarean delivery had an increased risk of serious opioid-related events compared to women who did not fill a postpartum opioid prescription. Low opioid doses were not associated with a significant increase in the risk of serious opioid-related events.