Over the past 15 years, the prevalence of opioid use disorder among pregnant women has increased 333% resulting in increased treatment needs during pregnancy.1 Medication-assisted treatment, consisting of opioid pharmacotherapy and behavioral health counseling, is the recommended, evidence-based treatment approach for opioid use disorder during pregnancy.2–5 A consensus of government agencies and professional organizations, including the American College of Obstetricians and Gynecologists, endorse the effectiveness of medication-assisted treatment for pregnant women, which improves maternal health outcomes by providing a stable opioid dosing regimen, reducing illicit drug use and decreasing behaviors that increase the risk for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection.2–5 Medication-assisted treatment use during pregnancy also improves neonatal health outcomes by minimizing the fetal stress response that results from illicit opioid use.6
Despite recommendations, medication-assisted treatment is underused during pregnancy. Evaluations of the Treatment Episodes Data Set indicate that only half of pregnant women with opioid use disorder admitted to substance-use treatment facilities in the United States received opioid pharmacotherapy, which has remained relatively unchanged over the past 20 years.7,8 Although previous research highlights significant unmet treatment need, prior analyses are limited to publicly funded treatment programs, have not investigated differences in opioid pharmacotherapy type (methadone vs buprenorphine), and have not evaluated behavioral health counseling use, an important component of comprehensive substance use treatment.7,8 As such, a population-level assessment of temporal trends in medication-assisted treatment use patterns during pregnancy remain largely unknown.
State Medicaid programs comprise the single largest payer in the United States for pregnancy and births9 and are the primary insurer for women with opioid use disorder.10,11 Because of this, many women with opioid use disorder reengage or newly engage in health care services during pregnancy and obstetric providers often assume the critical role of linking patients to treatment.12 Thus, the purpose of this research is to describe temporal trends in medication-assisted treatment use among pregnant women with opioid use disorder enrolled in Pennsylvania Medicaid. Specifically, our objectives are to evaluate 1) individual-level factors associated with medication-assisted treatment use during pregnancy, 2) temporal trends in methadone compared with buprenorphine use across rural and urban geographic regions, and 3) corresponding temporal trends in behavioral health counseling use. Our evaluation can help focus ongoing efforts to expand treatment access and availability during pregnancy.
For this retrospective cohort study, we used administrative health care claims data from the Pennsylvania Department of Health and Human Services Medicaid Program. This dataset is composed of claims, encounters, and pharmacy data for all Medicaid enrollees in Pennsylvania (including Medicaid managed care and traditional fee-for-service plans) from January 1, 2008, to September 30, 2015. In Pennsylvania, Medicaid provides reimbursement for all components of medication-assisted treatment including methadone, buprenorphine, and behavioral health counseling services.13 Demographic information, including age, race-ethnicity, and county of residence identified by enrollee zip codes were obtained from patient enrollment files. Medication-assisted treatment use data, including buprenorphine prescription fills, methadone treatment services and behavioral health counseling visits were obtained from pharmacy, professional, outpatient, and inpatient claims data. Pennsylvania Medicaid includes 5 regions that correspond to state population centers and are served by different managed care organizations.14 These Medicaid regional classifications were used to identify variation in medication-assisted treatment use across geographic regions within Pennsylvania. The study was approved by the University of Pittsburgh, Institutional Review Board.
We identified Medicaid-enrolled women ages 15–44 years who had a live birth from January 1, 2009 to September 30, 2015, and who had an International Classification of Diseases, Ninth Revision (ICD-9) diagnosis of opioid use disorder (304.0X, 304.7X, 305.50, 305.51, 305.52) during their pregnancy. Because a woman could have more than one pregnancy in the dataset, the pregnancy was chosen as the unit of analysis and medication-assisted treatment use during each pregnancy was evaluated. Live births were identified using the date of delivery in inpatient data. The pregnancy period was approximated using an algorithm validated by the National Committee for Quality Assurance.15 Using this method, we calculated 280 days before the date of delivery to approximate the date of conception. Because we focused on pregnancies that resulted in a preterm or term live birth, if a woman had an interpregnancy interval of less than 24 weeks (less than 168 days), the later pregnancy was excluded from the analysis.
Demographic characteristics included continuous as well as categorical measures of patient age (15–19, 20–34, 35–45 years), race (black, white, Asian, or other) and ethnicity (Hispanic or Latina). Urban compared with rural county of patient residence was defined based on the Rural Urban Commuting Area codes developed by the United States Department of Agriculture.16 All metropolitan areas are defined as urban, and rural areas include micropolitan areas, small towns, and rural areas. Medical comorbidities were identified by ICD-9 diagnostic codes that were associated with the pregnancy in the dataset. Medical comorbidity diagnoses included in the analysis were pregestational diabetes mellitus, chronic hypertension, asthma, thyroid disorder, HIV, HCV, and psychiatric disorders. Psychiatric disorders included major depressive disorder, bipolar disorder, and schizophrenia. Pregnancy-associated comorbidities included were gestational diabetes mellitus and gestational hypertensive disorders, which included gestational hypertension, preeclampsia, and eclampsia.
Substance use during pregnancy other than opioid use was identified by ICD-9 codes for tobacco, alcohol, cocaine, marijuana, amphetamine, hallucinogen, sedatives, and other substance use or drug dependence during pregnancy. Opioid pharmacotherapy use with either methadone or buprenorphine was also identified. Buprenorphine use was identified according to National Drug Codes for buprenorphine formulations and was defined as having 1 or more outpatient prescription fills for buprenorphine during pregnancy. Methadone use in pregnancy was identified through outpatient and professional claims for methadone treatment services (procedure codes H0020 or J1230) during pregnancy. We created three mutually exclusive opioid pharmacotherapy use groups: methadone only, any buprenorphine, and no pharmacotherapy. In a small number of pregnancies (n=365, 2.9%), we observed claims for both buprenorphine and methadone. Because of the extremely small sample size of the combined group, we categorized these pregnancies in the “any buprenorphine group.” We chose to create an “any buprenorphine” and a “methadone only” group because women are clinically more likely to switch from buprenorphine to methadone than methadone to buprenorphine during pregnancy.
Behavioral health counseling visits for each patient during pregnancy were identified in professional claims using procedure codes. We also categorized behavioral health counseling professional claims by the ICD-9 diagnostic codes associated with those claims. Counseling for drug or alcohol abuse was defined as a behavioral health professional claim associated with a diagnostic code for drug or alcohol abuse. Counseling for a psychiatric disorder was defined as a behavioral health professional claim associated with a diagnostic code for a psychiatric disorder.
Geographic trends in opioid pharmacotherapy use over time were evaluated across five Medicaid regions designated by the Pennsylvania Department of Health and Human Services: New East, Southeast, Lehigh-Capital, New West, and Southwest. Within each region, each county was defined as rural or urban according to each county's population density as defined by the Center for Rural Pennsylvania.17 The New West (Region 1) includes Erie and has 13 counties, 12 (92.3%) of which are rural. The New East (Region 2) includes Scranton and has 22 counties, 20 (90.9%) of which are rural. The Southwest (Region 3) includes the greater Pittsburgh area and has 14 counties, 11 (78.6%) of which are rural. The Lehigh-Capital (Region 4) includes Harrisburg and has 13 counties, five (38.5%) of which are rural. The Southeast (Region 5) includes the greater Philadelphia area and has 5 counties, none (0%) of which are rural.
We stratified the descriptive statistics of our study cohort by category of opioid pharmacotherapy to identify potential differences among the study population for each group using the χ2 test. Multivariable multinomial logistic regression was used to evaluate time trends in the prevalence of opioid pharmacotherapy use and negative binomial regression was used to evaluate the frequency of behavioral health visits during pregnancy. Both opioid pharmacotherapy and behavioral health visit models were adjusted for year of delivery, age, race, ethnicity, Medicaid region, medical comorbidities including psychiatric disorder, HCV and HIV infection, and substance use history including tobacco, alcohol, and substance use other than opioid use. After running the regression analysis, predictive margins of the outcome for each year were obtained to generate adjusted prevalence estimates in each year. Adjusted prevalence estimates in each year were reported with 95% CI.
We also calculated the changes over time in opioid pharmacotherapy use between geographic regions in Pennsylvania. Specifically, we calculated the percentage change from 2009 to 2015 in no opioid pharmacotherapy observed, buprenorphine, and methadone among pregnant women in each of the five geographic regions. All previously described variables were included as independent variables. P-values less than 0.05 were significant for all tests. All programming and statistical analyses were performed using the SAS 9.4.
From January 1, 2009, to September 30, 2015, we identified 354,891 Medicaid-enrolled pregnant women with live births. Within this sample, we identified a cohort of 12,587 pregnancies (3.5%) among 10,741 women who had a diagnosis of opioid used disorder (Table 1). Among 12,587 pregnancies, 5,553 (44.1%) did not use opioid pharmacotherapy during pregnancy. Of the 7,034 women who received opioid pharmacotherapy, 3,618 (51.4%) received methadone and 3,416 (48.6%) received buprenorphine. Overall, 4,930 (39.2%) women with opioid use disorder received behavioral health counseling during pregnancy. The majority of behavioral health claims (59.8%) were associated with drug and alcohol diagnoses with the remaining claims associated with psychiatric disorder diagnoses (7.9%), both drug and alcohol and psychiatric disorder diagnoses (13.2%), and a mix of other pregnancy-related diagnoses codes (19.1%).
Between 2009 and 2015, the adjusted prevalence of no opioid pharmacotherapy observed during pregnancy decreased from 52.6% (95% CI 50.1–55.1%) to 43.9% (95% CI 41.8–46.1%), with the most significant decrease occurring between 2009 and 2010 (9.5%) (Fig. 1). Increased use rates were largely due to buprenorphine use, which increased from 15.8% (95% CI 13.9–17.8%) to 30.9% (95% CI 28.8–33.0%) between 2009 and 2015. In contrast, methadone use decreased from 31.6% (95% CI 29.3–33.9%) to 25.2% (95% CI 23.3–27.1%) during the study period.
Between 2009 and 2015, an increase in the adjusted number of behavioral health visits occurred among women who received methadone during pregnancy, 5.7 (95% CI 4.3–7.1) compared with 6.4 (95% CI 4.9–7.9) visits, although the increase was not statistically significant (Fig. 2). There were no significant changes over time in the adjusted number of behavioral health visits during pregnancy among women using buprenorphine (3.1 vs 3.4 visits) and among women with no observed opioid pharmacotherapy use (3.6 vs 4.0 visits). However, in 2014 and 2015, we did find significant differences in the number of counseling visits during pregnancy by opioid pharmacotherapy type. In 2015, the adjusted number of behavioral health counseling visits during pregnancy was 3.4 (95% CI 2.6–4.1) among women using buprenorphine, 4.0 (95% CI 3.3–4.7) among women who did not use pharmacotherapy, and 6.4 (95% CI 4.9–7.9) among women using methadone (Fig. 2). Crude and adjusted prevalences and counts for Figures 1 and 2 are described in Appendixes 1 and 2, available online at http://links.lww.com/AOG/B349.
Between 2009 and 2015, we found a significant decrease in no opioid pharmacotherapy observed during pregnancy across all five Medicaid regions except for the New West (Region 1), which had a 0.6% increase. The New West region includes Erie and is the most rural Medicaid region with 12 of 13 counties (92.3%) designated as rural. Accordingly, we found an increase in buprenorphine use across all Medicaid regions with the most significant increases found in regions with large urban centers such as the Southwest (up 24.9%) and the Southeast (up 12.0%) compared with the largely rural New West region (up 5.2%). The Southwest region includes the greater Pittsburgh metropolitan area and the Southeast region includes the greater Philadelphia area. Conversely, we found a decrease in methadone use during pregnancy across all Medicaid regions except for the Lehigh-Capital region, which had a 2.9% increase in methadone use during pregnancy between 2009 and 2015 (Fig. 3).
Our evaluation of medication-assisted treatment use patterns among Medicaid-enrolled pregnant women with opioid use disorder demonstrates that opioid pharmacotherapy use increased by approximately 10% over the past decade, with use rates largely driven by an increase in buprenorphine use in urban geographic areas. Despite these gains, a significant gap between treatment need and receipt remains. In 2015, only 56% of women with opioid use disorder received opioid pharmacotherapy during pregnancy and fewer than 40% had a claim for behavioral health services. Behavioral health use varied by opioid pharmacotherapy type. In 2014 and 2015, women who received methadone had significantly more counseling visits during pregnancy than women who received buprenorphine and women with no pharmacotherapy observed. Therefore, despite current recommendations emphasizing the importance of medication-assisted treatment use during pregnancy, our findings demonstrate the need to further expand medication-assisted treatment access and availability for pregnant women with opioid use disorder.
Increases in pharmacotherapy use were largely driven by increases in buprenorphine use during pregnancy, which more than doubled over the study period and was accompanied by a corresponding decline in methadone use. Similar trends in pharmacotherapy use have been found in the general Medicaid population where buprenorphine has been the primary driver of increased pharmacotherapy use.18 Buprenorphine's office-based availability, pharmacy-based dispensing, and decreased risk of overdose compared with methadone have resulted in a multitude of initiatives from federal, state, and local agencies to rapidly expand the number of buprenorphine waivered physicians and outpatient programs to meet increased demands for substance use treatment.19,20 Further, randomized clinical trials have established buprenorphine's safety in pregnancy and demonstrated superior neonatal outcomes including a shorter treatment duration for neonatal abstinence syndrome and a shorter neonatal length of stay compared with methadone.21–23 As a result, buprenorphine has emerged a safe and effective, office-based treatment alternative to methadone and use during pregnancy has subsequently escalated.
Although pharmacotherapy use increased overall, significant disparities in pharmacotherapy use were found among teens and black and Hispanic women. Approximately 66% of pregnant women aged 15–19 did not receive opioid pharmacotherapy, compared with pregnant women aged 20–34 (43.8%) and aged 35 or older (40.6%), which reflects additional barriers for adolescent populations. In the United States, buprenorphine-naltrexone is approved only for persons age 16 years or older; persons younger than 18 years must fail two attempts at detoxification and provide a written consent from a parent before the initiation of methadone.24 Although pregnant adolescents are emancipated to make their own decisions regarding their pregnancies, many providers may not extend this autonomy to medication-assisted treatment, and provider willingness to provide medication-assisted treatment services to pregnant adolescents remains largely unknown. In 2016, a randomized clinical trial demonstrated that buprenorphine maintenance therapy was associated with significant improvements in treatment engagement and decreased rates of relapse among adolescents compared with medically-assisted withdrawal.25 As a result, the American Association of Pediatrics has advocated for increasing resources to improve medication-assisted treatment access for adolescent populations.26,27
Non-Hispanic black (73%) and Hispanic (64%) pregnant women were also significantly more likely to not use opioid pharmacotherapy than non-Hispanic white pregnant women (41%) suggesting racial and ethnic disparities in pharmacotherapy use. Further, among black and Hispanic pregnant women who received opioid pharmacotherapy, both groups were more likely to receive methadone compared with buprenorphine. Previous evaluations of racial and ethnic substance use treatment disparities in the adult, nonpregnant population have been mixed. In an analysis of the National Survey on Drug Use and Health, unadjusted differences in racial-ethnic substance use treatment receipt did not persist after adjustment for criminal history and socioeconomic factors.28 Likewise, racial-ethnic disparities in treatment completion using the Treatment Episodes Data Set-D data set were also largely explained by differences in socioeconomic status.29 Further evaluations are warranted to explain differential racial-ethnic opioid pharmacotherapy use rates among pregnant women.
Pharmacotherapy use during pregnancy increased across all Medicaid regions except for Region 1 (New West), the most rural region in Pennsylvania and was largely driven by increases in buprenorphine use in urban compared with rural geographic areas. Rural–urban disparities in pharmacotherapy use is of significant concern, because the prevalence of maternal opioid use and neonatal abstinence syndrome have disproportionately increased in rural areas across the United States and more than 80% of pregnant women living in rural areas experience barriers to substance use treatment services.30,31 In 2012, more than 40% of counties in the United States did not have at least one outpatient substance use treatment facility that accepted Medicaid and only 3% of programs were located in rural areas.32 Further, addiction stigma is especially powerful in rural areas,30,33 where fear of judgement, prosecution, and child welfare involvement may prevent many women from self-disclosure during pregnancy and delay substance use treatment engagement.34,35
The majority of pregnant women in our cohort did not receive behavioral health counseling during pregnancy, which is recommended as part of a comprehensive approach to treatment.5,36 We also found significant variability in the frequency of counseling visits during pregnancy by opioid pharmacotherapy type. In 2014 and 2015, pregnant women who received methadone had significantly more counseling visits compared to women who received buprenorphine and women who did not receive pharmacotherapy. Increased counseling among women who receive methadone is not unexpected as behavioral health services are often integrated into methadone treatment programs.37 In contrast, many outpatient buprenorphine treatment programs are only required to refer patients to behavioral health counseling and may not monitor compliance with attendance.38 Future research is necessary to determine the effect of counseling on substance use treatment outcomes among pregnant women and to identify subpopulations that may be most likely to benefit from behavioral health interventions.39,40
Our results must be interpreted with certain limitations. Our sample represents a cohort of women with opioid use disorder enrolled in Pennsylvania Medicaid, which may limit the generalizability of our findings to privately-insured or uninsured women and to women in other states. However, this limitation is minimized as Pennsylvania's Medicaid program is the fourth largest in the United States, with expenditures of $27.6 billion in 2016,13 and has demographic and socioeconomic profiles that closely track national averages.41 Although Pennsylvania Medicaid provides reimbursement for all components of medication-assisted treatment including methadone, buprenorphine, and behavioral health counseling, our results may not be generalizable to states whose Medicaid programs do not cover the full range of treatment services. Methadone is not included on Medicaid preferred drug lists in 20 states, whereas Medicaid covers buprenorphine in all 50 states.42 Further, women that were classified as not receiving pharmacotherapy in our data may have received pharmacotherapy from a non–Medicaid-billing provider or a provider that accepted cash payments for services.43 Finally, observational retrospective cohort analyses are vulnerable to bias and the possibility for confounding exists despite efforts to control for these factors.
Because many women with opioid use disorder newly engage or re-engage in health care services during pregnancy, obstetric providers play a critical role in linking pregnant women to treatment programs that provide opioid pharmacotherapy, behavioral health counseling and social services support.5,12 Future research efforts should focus on characterizing effective strategies to expand medication-assisted treatment access and availability for pregnant women such as identifying health care delivery models and clinical care pathways that increase medication-assisted treatment use and that can be implemented into a variety of obstetric settings.
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