Andrew R. Joyce

Risk Factors for Serious Prescription Opioid-Related Toxicity or Overdose among Veterans Health Administration Patients

OBJECTIVEnPrescription opioid use and deaths related to serious toxicity, including overdose, have increased dramatically in the United States since 1999. However, factors associated with serious opioid-related respiratory or central nervous system (CNS) depression or overdose in medical users are not well characterized. The objective of this study was to examine the factors associated with serious toxicity in medical users of prescription opioids.nnnDESIGNnRetrospective, nested, case-control analysis of Veterans Health Administration (VHA) medical, pharmacy, and health care resource utilization administrative data.nnnSUBJECTSnPatients dispensed an opioid by VHA between October 1, 2010 and September 30, 2012 (N=8,987).nnnMETHODSnCases (N=817) experienced life-threatening opioid-related respiratory/CNS depression or overdose. Ten controls were randomly assigned to each case (N=8,170). Logistic regression was used to examine associations with the outcome.nnnRESULTSnThe strongest associations were maximum prescribed daily morphine equivalent dose (MED)≥ 100 mg (odds ratio [OR]=4.1, 95% confidence interval [CI], 2.6-6.5), history of opioid dependence (OR=3.9, 95% CI, 2.6-5.8), and hospitalization during the 6 months before the serious toxicity or overdose event (OR=2.9, 95% CI, 2.3-3.6). Liver disease, extended-release or long-acting opioids, and daily MED of 20 mg or more were also significantly associated.nnnCONCLUSIONSnSubstantial risk for serious opioid-related toxicity and overdose exists at even relatively low maximum prescribed daily MED, especially in patients already vulnerable due to underlying demographic factors, comorbid conditions, and concomitant use of CNS depressant medications or substances. Screening patients for risk, providing education, and coprescribing naloxone for those at elevated risk may be effective at reducing serious opioid-related respiratory/CNS depression and overdose in medical users of prescription opioids.

Buprenorphine compared with methadone to treat pregnant women with opioid use disorder: a systematic review and meta-analysis of safety in the mother, fetus and child.

Abstract Aims To assess the safety of buprenorphine compared with methadone to treat pregnant women with opioid use disorder. Methods We searched PubMed, Embase and the Cochrane Library from inception to February 2015 for randomized controlled trials (RCT) and observational cohort studies (OBS) that compared buprenorphine with methadone for treating opioid‐dependent pregnant women. Two reviewers assessed independently the titles and abstracts of all search results and full texts of potentially eligible studies reporting original data for maternal/fetal/infant death, preterm birth, fetal growth outcomes, fetal/congenital anomalies, fetal/child neurodevelopment and/or maternal adverse events. We ascertained each studys risk of bias using validated instruments and assessed the strength of evidence for each outcome using established methods. We computed effect sizes using random‐effects models for each outcome with two or more studies. Results Three RCTs (n = 223) and 15 cohort OBSs (n = 1923) met inclusion criteria. In meta‐analyses using unadjusted data and methadone as comparator, buprenorphine was associated with lower risk of preterm birth [RCT risk ratio (RR)u2009=u20090.40, 95% confidence interval (CI)u2009=u20090.18, 0.91; OBS RRu2009=u20090.67, 95% CIu2009=u20090.50, 0.90], greater birth weight [RCT weighted mean difference (WMD)u2009=u2009277u2009g, 95% CIu2009=u2009104, 450; OBS WMDu2009=u2009265u2009g, 95% CIu2009=u2009196, 335] and larger head circumference [RCT WMDu2009=u20090.90u2009cm, 95% CIu2009=u20090.14, 1.66; OBS WMDu2009=u20090.68u2009cm, 95% CIu2009=u20090.41, 0.94]. No treatment differences were observed for spontaneous fetal death, fetal/congenital anomalies and other fetal growth measures, although the power to detect such differences may be inadequate due to small sample sizes. Conclusions Moderately strong evidence indicates lower risk of preterm birth, greater birth weight and larger head circumference with buprenorphine treatment of maternal opioid use disorder during pregnancy compared with methadone treatment, and no greater harms.

Development of a Risk Index for Serious Prescription Opioid‐Induced Respiratory Depression or Overdose in Veterans’ Health Administration Patients

Abstract Objective Develop a risk index to estimate the likelihood of life‐threatening respiratory depression or overdose among medical users of prescription opioids. Subjects, Design, and Methods A case‐control analysis of administrative health care data from the Veterans’ Health Administration identified 1,877,841 patients with a pharmacy record for an opioid prescription between October 1, 2010 and September 30, 2012. Overdose or serious opioid‐induced respiratory depression (OSORD) occurred in 817. Ten controls were selected per case (nu2009=u20098,170). Items for an OSORD risk index (RIOSORD) were selected through logistic regression modeling, with point values assigned to each predictor. Modeling of risk index scores produced predicted probabilities of OSORD; risk classes were defined by the predicted probability distribution. Results Fifteen variables most highly associated with OSORD were retained as items, including mental health disorders and pharmacotherapy; impaired drug metabolism or excretion; pulmonary disorders; specific opioid characteristics; and recent hospital visits. The average predicted probability of experiencing OSORD ranged from 3% in the lowest risk decile to 94% in the highest, with excellent agreement between predicted and observed incidence across risk classes. The models C‐statistic was 0.88 and Hosmer–Lemeshow goodness‐of‐fit statistic 10.8 (Pu2009>u20090.05). Conclusion RIOSORD performed well in identifying medical users of prescription opioids within the Veterans’ Health Administration at elevated risk of overdose or life‐threatening respiratory depression, those most likely to benefit from preventive interventions. This novel, clinically practical, risk index is intended to provide clinical decision support for safer pain management. It should be assessed, and refined as necessary, in a more generalizable population, and prospectively evaluated.

A pharmacoepidemiologic analysis of the impact of calendar packaging on adherence to self-administered medications for long-term use.

BACKGROUNDnCalendar blister packaging (CBP) that incorporates a day or date feature is a simple medication packaging technology that is designed to improve medication adherence and persistence.nnnOBJECTIVEnThis study was conducted to assess the effect of a new calendar packaging technology on prescription refill adherence and persistence for daily, self-administered, long-term medication use.nnnMETHODSnAnonymized pharmacy dispensing data from a large US mass merchandiser were analyzed. This retrospective cohort study included people aged 18 to 75 years who filled prescriptions for oral lisinopril or enalapril (control group) at a study pharmacy during 1 year before and after the switch of lisinopril packaging from vials to CBP. Cohorts were stratified into new and prevalent medication users. We used linear and logistic regression modeling and propensity score matching to assess the impact of CBP on refill adherence, using medication possession ratio (MPR) and proportion of days covered (PDC), and persistence using length of therapy (LOT).nnnRESULTSnOur sample comprised 76,321 new users and 249,040 prevalent users. Across all user, medication, and packaging groups, the mean unadjusted LOT decreased in the follow-up year, possibly due to economic recession. The LOT decline was attenuated in the CBP cohort. After adjustment for covariates, CBP use in new and prevalent medication users was associated with significantly higher LOT and PDC but not MPR. The odds of achieving PDC ≥80% were higher by 15% in new users (odds ratio [OR] = 1.15; 95% CI, 1.09-1.21) and 12% in prevalent users (OR = 1.12; 95% CI, 1.09-1.15) who switched to CBP, compared with continued vial use.nnnCONCLUSIONSnCBP of medication prescribed for daily, self-administered, long-term use was associated with modest improvement in prescription refill adherence and persistence. An adherence strategy of even small effect size that is broadly implemented on a population level could significantly leverage therapeutic effect and provide substantial cumulative public health benefit. Clinical benefit, or harm, associated with use of CBP should be investigated. Usability assessments of CBP in patient subgroups may provide insight about differential impact on adherence and persistence.

Gene expression profiling of peripheral blood leukocytes identifies potential novel biomarkers of chronic obstructive pulmonary disease in current and former smokers

Background: Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease with associated systemic effects. Objective: To use gene expression microarrays in peripheral blood leukocytes of current and former cigarette smokers to identify differences associated with COPD. Materials and methods: Random forest modelling and a split-sample case–control approach were used to identify candidate predictors. Results: We identified 1013 genes and one smoking exposure variable that differentiated current and former smokers with or without COPD. This predictor set was reduced to a nine-gene classifier (IL6R, CCR2, PPP2CB, RASSF2, WTAP, DNTTIP2, GDAP1, LIPE and RPL14). Conclusion: These gene expression profiles represent potential biomarkers for COPD and may help increase mechanistic understanding of the disease.

A statistical method for excluding non-variable CpG sites in high-throughput DNA methylation profiling

BackgroundHigh-throughput DNA methylation arrays are likely to accelerate the pace of methylation biomarker discovery for a wide variety of diseases. A potential problem with a standard set of probes measuring the methylation status of CpG sites across the whole genome is that many sites may not show inter-individual methylation variation among the biosamples for the disease outcome being studied. Inclusion of these so-called non-variable sites will increase the risk of false discoveries and reduce statistical power to detect biologically relevant methylation markers.ResultsWe propose a method to estimate the proportion of non-variable CpG sites and eliminate those sites from further analyses. Our method is illustrated using data obtained by hybridizing DNA extracted from the peripheral blood mononuclear cells of 311 samples to an array assaying 1505 CpG sites. Results showed that a large proportion of the CpG sites did not show inter-individual variation in methylation.ConclusionsOur method resulted in a substantial improvement in association signals between methylation sites and outcome variables while controlling the false discovery rate at the same level.

Validation of a Screening Risk Index for Serious Prescription Opioid-Induced Respiratory Depression or Overdose in a US Commercial Health Plan Claims Database

Abstract Objective To validate a risk index that estimates the likelihood of overdose or serious opioid-induced respiratory depression (OIRD) among medical users of prescription opioids. Subjects and Methods A case-control analysis of 18,365,497 patients with an opioid prescription from 2009 to 2013 in the IMS PharMetrics Plus commercially insured health plan claims database (CIP). An OIRD event occurred in 7,234 cases. Four controls were selected per case. Validity of the Risk Index for Overdose or Serious Opioid-induced Respiratory Depression (RIOSORD), developed previously using Veterans Health Administration (VHA) patient data, was assessed. Multivariable logistic regression was used within the CIP study population to develop a slightly refined RIOSORD. The composition and performance of the CIP-based RIOSORD was evaluated and compared with VHA-based RIOSORD. Results VHA-RIOSORD performed well in discriminating OIRD events in CIP (C-statistic = 0.85). Additionally, re-estimation of logistic model coefficients in CIP yielded a 0.90 C-statistic. The resulting comorbidity and pharmacotherapy variables most highly associated with OIRD and retained in the CIP-RIOSORD were largely concordant with VHA-RIOSORD. These variables included neuropsychiatric and cardiopulmonary disorders, impaired drug excretion, opioid characteristics, and concurrent psychoactive medications. The average predicted probability of OIRD ranged from 2% to 83%, with excellent agreement between predicted and observed incidence across risk classes. Conclusions RIOSORD had excellent predictive accuracy in a large population of US medical users of prescription opioids, similar to its performance in VHA. This practical risk index is designed to support clinical decision-making for safer opioid prescribing, and its clinical utility should be evaluated prospectively.

A Swedish Population-based Study of Adverse Birth Outcomes among Pregnant Women Treated with Buprenorphine or Methadone: Preliminary Findings

Background Untreated opioid dependence in pregnant women is associated with adverse birth outcomes. Buprenorphine and methadone are options for opioid agonist medication-assisted treatment during pregnancy. Objective The aim of this study was to describe adverse birth outcomes observed with buprenorphine or methadone treatment compared to the general population in Sweden. Methods Pregnant women and their corresponding births during 2005–2011 were identified in the Swedish Medical Birth Register. Data on stillbirth, neonatal/infant death, mode of delivery, gestational age at birth, Apgar score, growth outcomes, neonatal abstinence syndrome, and congenital malformations were examined. Frequencies were compared using two-sided Fishers exact tests. Unadjusted estimates of birth outcomes for women treated with buprenorphine or methadone were compared to the registered general population. Results A total of 746,257 pregnancies among 538,178 unique women resulted in 746,485 live births. Among the 194 women treated with buprenorphine (N = 176) or methadone (N = 52), no stillbirths or neonatal/infant deaths occurred. Neonatal abstinence syndrome developed in 23.3% and 38.5% of infants born to mothers treated with buprenorphine and methadone, respectively. The frequency of the selected adverse birth outcomes assessed in women treated with buprenorphine as compared to the general population was not significantly different. However, a significantly higher frequency of preterm birth and congenital malformations was observed in women treated with methadone as compared to the general population. Compared with the general population, methadone-treated women were significantly older than buprenorphine-treated women, and both treatment groups began prenatal care later, were more likely to smoke cigarettes, and did not cohabitate with the babys father. Conclusions An increased frequency of the selected adverse birth outcomes was not observed with buprenorphine treatment during pregnancy. Twofold increased frequency of preterm birth [2.21 (1.11, 4,41)] and congenital malformations [2.05 (1.08, 3.87)] was observed in the methadone group, which may be partly explained by older average maternal age and differences in other measured and unmeasured confounders.

Risk Factors for Serious Prescription Opioid-Induced Respiratory Depression or Overdose: Comparison of Commercially Insured and Veterans Health Affairs Populations

Abstract Objective To characterize the risk factors associated with overdose or serious opioid-induced respiratory depression (OIRD) among medical users of prescription opioids in a commercially insured population (CIP) and to compare risk factor profiles between the CIP and Veterans Health Administration (VHA) population. Subjects and Methods Analysis of data from 18,365,497 patients in the IMS PharMetrics Plus health plan claims database (CIP) who were dispensed a prescription opioid in 2009 to 2013. Baseline factors associated with an event of serious OIRD among 7,234 cases and 28,932 controls were identified using multivariable logistic regression. The CIP risk factor profile was compared with that from a corresponding logistic regression among 817 VHA cases and 8,170 controls in 2010 to 2012. Results The strongest associations with serious OIRD in CIP were diagnosed substance use disorder (odds ratio [OR] = 10.20, 95% confidence interval [CI] = 9.06–11.40) and depression (OR = 3.12, 95% CIu2009=u20092.84–3.42). Other strongly associated factors included other mental health disorders; impaired liver, renal, vascular, and pulmonary function; prescribed fentanyl, methadone, and morphine; higher daily opioid doses; and concurrent psychoactive medications. These risk factors, except depression, vascular disease, and specific opioids, largely aligned with VHA despite CIP being substantially younger, including more females and less chronic disease, and having greater prescribing prevalence of higher daily opioid doses, specific opioids, and most selected nonopioids. Conclusions Risk factor profiles for serious OIRD among US medical users of prescription opioids with private or public health insurance were largely concordant despite substantial differences between the populations in demographics, clinical conditions, health care delivery systems, and clinical practices.

Role of plasma membrane disruption in reference moist smokeless tobacco-induced cell death

An oral injury is thought to presage the development of mucosal lesions that are common in moist smokeless tobacco (MST) users. The abrasion or mechanical stress caused by direct contact of MST with the oral mucosa may contribute to this injury by causing transient disruptions in the cell membrane. In order to test this hypothesis, we developed an in vitro exposure system that directly exposes cells to reference MST on a rocking platform to simulate the abrasion that might be experienced in the oral cavity when using MST. Using this treatment paradigm, we monitored plasma membrane disruption as a measure of cell wounding caused by direct interaction of the tobacco material itself with monolayer cultures of Het-1A immortalized human esophageal cells as a potential contributor to the injury process. We found that a washed reference MST preparation, in which MST-associated chemicals were removed but the tobacco material retained, causes cell wounding as indicated by the uptake through plasma membrane disruptions of a fluorescent marker normally impermeable to the cell. Having established that non-chemical properties of MST cause cell wounding, subsequent experiments revealed that cell wounding during simultaneous exposure to an aqueous MST-extract result in greater than additive cell death when compared to treatment with washed MST or MST-extract alone. Furthermore, we found that the high levels of free calcium found in MST-extract appear to be playing an important role. Taken together, these results indicate that MST-induced oral injury may result from a combined interaction of physical disruption of the plasma membrane by the tobacco material itself and the adverse effects of MST chemical constituents, notably high levels of calcium, that gain entry to the cell by way of MST-induced cell wounding.