Association Between Gabapentin Receipt for Any Indication and Alcohol Use Disorders Identification Test-Consumption Scores Among Clinical Subpopulations With and Without Alcohol Use Disorder

Mining clinical data for novel medications to treat alcohol use disorder

BACKGROUND

Alcohol use disorder (AUD) is a highly prevalent and often debilitating condition associated with high morbidity and mortality. Current AUD medications have limited efficacy and uptake. Alternative pharmacological options are needed.

METHODS

We constructed a mechanistic tree of all US Food and Drug Administration approved medications and used a tree-based scan statistic, TreeScan, to identify medications associated with greater than expected improvements in alcohol consumption. Our cohort included all United States (US) Department of Veterans Affairs (VA) patients with a diagnosis of AUD between 10/1/1999 and 9/30/2019 with multiple Alcohol Use Disorders Identification Test-Consumption Module scores within the VA electronic health record data.

RESULTS

Medications statistically associated with decreased alcohol consumption had, at large, minor effect sizes. Medications used in the treatment of chronic or life-threatening conditions like diabetes, chronic kidney disease, hepatitis C virus, or cancer produced larger effect sizes. Asenapine, an atypical antipsychotic, had a large effect with an observed to expected ratio of 1.78 (p = 0.003). Our findings were replicated in a propensity score matched population.

CONCLUSION

Most medications significantly associated with decreased alcohol consumption in our analysis were either contraindicated with alcohol or likely attributable to patients abstaining from alcohol due to severe illness. However, the large effect of asenapine is notable, and a worthwhile candidate for more careful analysis.

Association of topiramate prescribed for any indication with reduced alcohol consumption in electronic health record data

BACKGROUND AND AIMS

Topiramate is a medication that is widely prescribed to treat a variety of conditions, including alcohol use disorder (AUD). We used electronic health record (EHR) data to measure topiramate's effects on drinking in individuals differentiated by a history of AUD.

DESIGN

Parallel-groups comparison of patients prescribed topiramate and a propensity score-matched comparison group.

SETTING

A large US integrated health-care system.

PARTICIPANTS

Patients with Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) scores prior to and after a minimum of 180 days of topiramate prescription for any indication and a propensity score-matched group. The sample included 5918 patients with an electronic health record diagnosis of alcohol use disorder at any time (AUD-hx-pos) (1738 topiramate-exposed and 4180 controls) and 23 614 patients with no EHR diagnosis of AUD (AUD-hx-neg) (6324 topiramate-exposed and 17 290 controls).

MEASUREMENTS

Regression analyses compared difference-in-difference (DiD) estimates, separately by AUD history. DiD estimates represent exposure-group (i.e. topiramate versus control) differences on the pre-post difference in AUDIT-C score. Effects of baseline AUDIT-C score and daily topiramate dosage were also tested.

FINDINGS

AUD-hx-neg patients who received topiramate had a greater reduction in AUDIT-C score (-0.11) than matched controls (-0.04). This yielded a DiD score of -0.07 [95% confidence interval (CI) = -0.11,-0.03; P = 0.002], with the greatest effect among AUD-hx-neg patients with a baseline AUDIT-C score of 4+ (DiD = -0.35, 95% CI = -0.49, -0.21; P < 0.0001) and those prescribed > 150 mg/day of the medication (DiD = -0.15, 95%CI = -0.23, -0.07; P < 0.001).

DISCUSSION

Among individuals with no history of alcohol use disorder, topiramate appears to be associated with reduced drinking. This small effect is most evident among patients with higher baseline drinking levels and at a higher average daily topiramate dosage.

Treatment for alcohol use disorder among persons with and without HIV in a clinical care setting in the United States

BACKGROUND

Alcohol use disorders (AUD) can lead to poor health outcomes. Little is known about AUD treatment among persons with HIV (PWH). In an integrated health system in Northern California, 2014-2017, we compared AUD treatment rates between PWH with AUD and persons without HIV (PWoH) with AUD.

METHODS

Using Poisson regression with GEE, we estimated prevalence ratios (PRs) comparing the annual probability of receiving AUD treatment (behavioral intervention or dispensed medication), adjusted for sociodemographics, psychiatric comorbidities, insurance type, and calendar year. Among PWH, we examined independent AUD treatment predictors using PRs adjusted for calendar year only.

RESULTS

PWH with AUD (N = 633; 93% men, median age 49) were likelier than PWoH with AUD (N = 7006; 95% men, median age 52) to have depression (38% vs. 21%) and a non-alcohol substance use disorder (SUD, 48% vs. 25%) (both P < 0.01). Annual probabilities of receiving AUD treatment were 45.4% for PWH and 34.4% for PWoH. After adjusting, there was no difference by HIV status (PR 1.02 [95% CI 0.94-1.11]; P = 0.61). Of treated PWH, 59% received only a behavioral intervention, 5% only a medication, and 36% both, vs. 67%, 4%, 30% for treated PWoH, respectively. Irrespective of HIV status, the most common medication was gabapentin. Among PWH, receiving AUD treatment was associated with having depression (PR 1.78 [1.51-2.10]; P < 0.01) and another SUD (PR 2.68 [2.20-3.27]; P < 0.01).

CONCLUSIONS

PWH with AUD had higher AUD treatment rates than PWoH with AUD in unadjusted but not adjusted analyses, which may be explained by higher psychiatric comorbidity burden among PWH.

Effectiveness of spironolactone dispensation in reducing weekly alcohol use: a retrospective high-dimensional propensity score-matched cohort study

There is a need to increase the armamentarium of pharmacotherapies for alcohol use disorder (AUD). Recent research suggests that mineralocorticoid receptor (MR) antagonism via spironolactone may represent a novel pharmacological treatment for AUD. We conducted a pharmacoepidemiologic retrospective cohort study (June 1, 2014 to May 31, 2018) to examine whether spironolactone dispensation (≥90 continuous days), for any indication, is associated with changes in weekly alcohol use about 6 months later. We compared 523 spironolactone-treated adults and 2305 untreated adults, matched on high-dimensional propensity scores created from a set of predefined (sociodemographic and health characteristics, diagnoses, and service utilization) and empirical electronic health record-derived covariates. The sample was 57% female and 27% non-White with a mean age of 59.2 years (SD = 19.3). Treated patients reduced their weekly alcohol use by 3.50 drinks (95% CI = -4.22, -2.79), while untreated patients reduced by 2.74 drinks (95% CI = -3.22, -2.26), yielding a significant difference of 0.76 fewer drinks (95% CI = -1.43, -0.11). Among those who drank >7 drinks/week at baseline, treated patients, compared to untreated patients, reported a greater reduction in weekly alcohol use by 4.18 drinks (95% CI = -5.38, -2.97), while there was no significant difference among those who drank less. There was a significant dose-response relationship between spironolactone dosage and change in drinks/week. Pending additional evidence on its safety and efficacy in individuals with AUD, spironolactone (and MR blockade, at large) may hold promise as a pharmacotherapy for AUD.

Pilot randomized placebo-controlled clinical trial of high-dose gabapentin for alcohol use disorder

BACKGROUND

Despite advances in the development of pharmacotherapy for alcohol use disorder (AUD), there remains a need for medications that can be administered to actively drinking outpatients to promote a reduction in harmful alcohol consumption. The primary aim of this pilot study was to determine whether high-dose gabapentin (3600 mg/daily) is more effective than placebo in reducing harmful alcohol consumption in outpatients with AUD.

METHODS

Forty patients (27 men) who met DSM-IV-TR criteria for alcohol dependence and reporting at least 4 heavy drinking days (HDD) per week were recruited at a single site. Participants were actively drinking at study entry and received double-blind gabapentin (3600 mg/day; n = 19) or placebo (n = 20) for 8 weeks. Study medication was titrated over 5 days and administered in three divided doses (1200 mg three times per day). The proportion of HDD (primary outcome) and percent days abstinent (PDA; secondary outcome) were analyzed using generalized longitudinal mixed models with the predictors being study arm, week, study arm by week interaction, and corresponding baseline drinking measure.

RESULTS

There was a significant interaction between study arm and week for the proportion of HDD per week, F (7, 215) = 3.33, p = 0.002 . There was also a significant interaction between study arm and week for PDA per week, F (7, 215) = 3.11, p = 0.004. The overall retention rate was 67.5% with no significant difference in time-to-dropout between treatment groups. There were no serious adverse events. No participants were removed from the trial due to the development of moderate-to-severe alcohol withdrawal (CIWA-Ar ≥ 13).

CONCLUSIONS

Gabapentin treatment rapidly titrated to a dosage of 3600 mg/day is associated with a reduction in the proportion of HDD per week and an increase in PDA per week in actively drinking outpatients with AUD. High-dose gabapentin is potentially a feasible approach to treating AUD and deserving of further study.

Prospective randomized pharmacogenetic study of topiramate for treating alcohol use disorder

In a prior study, topiramate reduced heavy drinking among individuals who sought to reduce their drinking, with the effect moderated by a single nucleotide polymorphism (SNP; rs2832407) in GRIK1, which encodes the kainate GluK1 receptor subunit (Kranzler et al. 2014). The present study sought to replicate prospectively the effect of topiramate and rs2832407 in patients with DSM-5 alcohol use disorder (AUD) who sought to reduce or stop their drinking. We stratified the randomization on genotype (rs2832407*C-allele homozygotes vs. A-allele carriers) and assigned 170 European-American participants (71.2% male) to receive 12 weeks of treatment with topiramate (N  = 85), at a maximal daily dosage of 200 mg, or matching placebo (N = 85). At each of nine treatment visits participants received brief counseling to reduce drinking and increase abstinent days. We hypothesized that topiramate-treated patients with the rs2832407*CC genotype would reduce heavy drinking days (HDDs) more than the other three groups. The rate of treatment completion was 91.8% in both groups. The mean number of HDDs per week in the placebo group was 1.67 (95% CI = (1.29, 2.16), p = 0.0001) times greater than in the topiramate group, which was confirmed by the topiramate group's significantly greater reduction in the concentration of the liver enzyme γ-glutamyltransferase and lower alcohol-related problems score. There was no significant difference in topiramate's effect on HDDs between genotype groups. Although consistent with other studies showing a reduction in heavy drinking with topiramate treatment, the prior finding of a moderating effect of rs2832407 genotype was not replicated in this prospective trial.

Impact of behavioral and medication treatment for alcohol use disorder on changes in HIV-related outcomes among patients with HIV: A longitudinal analysis

BACKGROUND

For people with HIV (PWH) and alcohol use disorder (AUD) who initiated behavioral treatment (BAUD) we: 1) describe BAUD intensity and medication (MAUD); and 2) examine whether BAUD and MAUD were associated with changes in HIV-related outcomes (CD4 cell count, HIV-1 viral load [VL], VACS Index score 2.0, and antiretroviral [ARV] adherence) from before to one year after treatment initiation.

METHODS

We used Veterans Aging Cohort Study (VACS) data to describe BAUD intensity and MAUD (acamprosate, disulfiram, and naltrexone, gabapentin or topiramate). Linear regression models estimated changes in outcomes and included BAUD, MAUD, age and race/ethnicity.

RESULTS

We identified 7830 PWH who initiated BAUD from 01/2008-09/2017. Median age was 53, 60% were African-American and 28% white. BAUD intensity groups were: 1) Single Visit - 35%; 2) Minimal - 44% recieved ∼2 visits during first month; 3) Sustained Moderate - 17% recieved ∼8 visits/month initially; and 4) Intensive - 4% started out receiving ∼14-16 visits/month. Only 9% recieved MAUD, the majority of which was gabapentin. Among those with detectable VL: all HIV-related outcomes improved more among those with more intensive BAUD. Among those with undetectable VL: adherence improved more among those with greater BAUD intensity. MAUD was associated with increased CD4 among those with detectable VL and with improved adherence among both groups.

CONCLUSION

Of those with >1 BAUD visit, only 21% received at least moderate BAUD and 9% received at least 6 months of MAUD. Increasing AUD treatment intensity may improve HIV-related outcomes, especially among those with detectable VL.

Gabapentinoids for treatment of alcohol use disorder: A systematic review and meta-analysis

OBJECTIVE

Gabapentin (GBP) and pregabalin (PGB) have been used to treat alcohol use disorder (AUD) and alcohol withdrawal, but with inconsistent results. In this meta-analysis, we explored the effects of GBP/PGB treatment on AUD and their effects on withdrawal, craving, depression, and sleep disturbance in AUD patients.

METHODS

We carried out a systematic review and meta-analysis of randomized controlled trials comparing the effects of GBP/PGB on AUD with those of a placebo or control treatment. Electronic databases were searched for relevant articles published before September 2019. The primary outcome was defined as the efficacy measure on achieving abstinence or reducing alcohol consumption in a hierarchical order. We included 16 studies in our meta-analysis.

RESULTS

Overall, GBP had no significant benefit comparing to placebo or control treatment (Hedges' g = 0.0725, p = 0.6743). For specific alcohol-related outcome, GBP had significant effect on percentage of heavy drink (Hedges' g = 0.5478, p = 0.0441) and alcohol withdrawal symptoms (Hedges' g = 0.2475, p = 0.0425). GBP/PGB did not have significant beneficial effect on craving, depressive symptoms, or sleep disturbance. Instability was shown in sensitivity analyses of some above results.

CONCLUSIONS

GBP may be helpful to reduce AUD patients' heavy drinking behavior and withdrawal, but more studies are needed for drawing conclusions.

Safety of Gabapentin Prescribed for Any Indication in a Large Clinical Cohort of 571,718 US Veterans with and without Alcohol Use Disorder

BACKGROUND

Gabapentin is prescribed for seizures and pain and has efficacy for treating alcohol use disorder (AUD) starting at doses of 900 milligrams per day (mg/d). Recent evidence suggests safety concerns associated with gabapentin including adverse neurologic effects. Individuals with hepatitis C (HCV), HIV, or AUD may be at increased risk due to comorbidities and potential medication interactions.

METHODS

We identified patients prescribed gabapentin for ≥ 60 days for any indication between 2002 and 2015. We propensity-score matched each gabapentin-exposed patient with up to 5 gabapentin-unexposed patients. We followed patients for 2 years or until diagnosed with (i) falls or fractures, or (ii) altered mental status using validated ICD-9 diagnostic codes. We used Poisson regression to estimate incidence rates and relative risk (RR) of these adverse events in association with gabapentin exposure overall and stratified by age, race/ethnicity, sex, HCV, HIV, AUD, and dose.

RESULTS

Incidence of falls or fractures was 1.81 per 100 person-years (PY) among 140,310 gabapentin-exposed and 1.34/100 PY among 431,408 gabapentin-unexposed patients (RR 1.35, 95% confidence interval [CI] 1.28 to 1.44). Incidence of altered mental status was 1.08/100 PY among exposed and 0.97/100 PY among unexposed patients, RR of 1.12 (95% CI 1.04 to 1.20). Excess risk of falls or fractures associated with gabapentin exposure was observed in all subgroups except patients with HCV, HIV, or AUD; however, these groups had elevated incidence regardless of exposure. There was a clear dose-response relationship for falls or fractures with highest risk observed among those prescribed ≥ 2,400 mg/d (RR 1.90, 95% CI 1.50 to 2.40). Patients were at increased risk for altered mental status at doses 600 to 2,399 mg/d; however, low number of events in the highest dose category limited power to detect a statistically significant association ≥ 2,400 mg/d.

CONCLUSIONS

Gabapentin is associated with falls or fractures and altered mental status. Clinicians should be monitoring gabapentin safety, especially at doses ≥ 600 mg/d, in patients with and without AUD.

On the path towards personalized medicine: Implications of pharmacogenetic studies of alcohol use disorder medications

Introduction

The heritability of alcohol use disorder (AUD) is estimated to be ~50%; however, the genetic basis of the disease is still poorly understood. The genetic variants identified thus far only explain a small percentage of AUD phenotypic variability. While genome-wide association studies (GWAS) are impacted by technical and methodological limitations, genetic variants that have been identified independently of GWAS findings can moderate the efficacy of AUD medications.

Areas Covered

This review discusses findings from clinical pharmacogenetic studies of AUD medications. While the pharmacogenetic studies reviewed involve several genetic variants in the major neurotransmitter systems, genetic loci in the opioid system have garnered the most attention.

Expert Opinion

The clinical utility of pharmacogenetics in AUD populations is uncertain at this time. There are several ongoing prospective clinical trials that will enhance knowledge regarding the applicability of pharmacogenetics in clinical populations. We recommend that future work in this area consider reverse translating from genotype to phenotype, mapping genes to stages of the addiction cycle, mapping genes to neural circuits, and harnessing large population-based cohorts.

Prospects for pharmacotherapies to treat alcohol use disorder: an update on recent human studies

PURPOSE OF REVIEW

The aim of this study was to provide an update on medication development efforts for alcohol use disorder (AUD) by reviewing recently published (past 2 years) human studies that evaluated medications' effects on alcohol-related outcomes.

RECENT FINDINGS

Forty-five publications were found suitable for this review. A variety of compounds have been tested in the past 2 years as potential pharmacological options for AUD, including medications that act on multiple targets (topiramate, aripiprazole, quetiapine), calcium channels (gabapentin), gamma-Aminobutyric acid receptors (baclofen, diazepam), glutamate receptors (ifenprodil, memantine, glycine), nicotinic acetylcholine receptors (varenicline, mecamylamine), α1 adrenergic receptors (prazosin, doxazosin), neuroendocrine pathways (oxytocin, a vasopressin receptor 1b antagonist, a ghrelin receptor inverse agonist) and others (samidorphan, ibudilast, N-acetylcysteine, citoline). Important findings and limitations regarding the effects of these medications on alcohol-related outcomes are discussed.

SUMMARY

There is a critical need to increase the armamentarium of medications for AUD. Human laboratory studies may help screen and prioritize promising targets and compounds before running large clinical trials. Given the complexity of AUD and the heterogeneity of afflicted patients, future studies should also investigate potential moderators and predictors of response to each pharmacological intervention.