Effects of topiramate therapy on serum bicarbonate concentration in a sample of 10,279 veterans.

BACKGROUND: Topiramate, which is increasingly being used to treat alcohol use disorder (AUD), is commonly associated with reduced serum bicarbonate concentrations. However, estimates of the prevalence and magnitude of this effect are from small samples and do not address whether topiramate's effects on acid-base balance differ in the presence of an AUD or by topiramate dosage. METHODS: Veterans Health Administration electronic health record (EHR) data were used to identify patients with a minimum of 180 days of topiramate prescription for any indication and a propensity score-matched control group. We differentiated patients into two subgroups based on the presence of a diagnosis of AUD in the EHR. Baseline alcohol consumption was determined using Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) scores in the EHR. Analysis also included a three-level measure representing mean daily dosage. The topiramate-associated changes in serum bicarbonate concentration were estimated in difference-in-differences linear regression models. A serum bicarbonate concentration <17 mEq/L was considered to represent possible clinically significant metabolic acidosis. RESULTS: The cohort comprised 4287 topiramate-treated patients and 5992 propensity score-matched controls with a mean follow-up period of 417 days. The mean topiramate-associated reductions in serum bicarbonate concentration were <2 mEq/L in the low (≤88.75), medium (>88.75 and ≤141.70), and high (>141.70) mg/day dosage tertiles, irrespective of AUD history. Concentrations <17 mEq/L occurred in 1.1% of topiramate-treated patients and 0.3% of controls and were not associated with alcohol consumption or an AUD diagnosis. CONCLUSIONS: The excess prevalence of metabolic acidosis associated with topiramate treatment does not differ with dosage, alcohol consumption, or the presence of an AUD. Baseline and periodic serum bicarbonate concentration measurements are recommended during topiramate therapy. Patients prescribed topiramate should be educated about the symptoms of metabolic acidosis and urged to report their occurrence promptly to a healthcare provider.

Predictors of Treatment Referral after AUDIT-C Screening for Heavy Drinking.

OBJECTIVES: The Veterans Health Administration has implemented annual screening for heavy drinking during primary care encounters using the 3-item Alcohol Use Disorders Identification Test - Consumption (AUDIT-C) questionnaire and made specialized services available to patients with alcohol use disorders (AUDs). We sought to identify the factors that influence whether a patient who has an elevated AUDIT-C score receives appropriate care in the context of an integrated mental health services program. We focused on higher AUDIT-C scores, as these are seen in individuals who are most likely to have a moderate-to-severe AUD and more severe alcohol-related consequences. METHODS: Utilizing electronic health record data, we conducted a four-year retrospective study of veterans at high-risk for an AUD, based upon an AUDIT-C score >=8 recorded during a primary care encounter at a Veterans Affairs Medical Center and its community-based outpatient clinics. RESULTS: In multivariate analysis, the predictors of treatment referral were younger age, being non-white, higher AUDIT-C score, and main campus location. Among patients referred for treatment, younger age and being white were associated with an increased likelihood of completing a pre-treatment assessment. CONCLUSIONS: Efforts to increase the consistency of treatment referrals, according to established clinical guidelines, could enhance the effectiveness of AUDIT-C screening during primary care visits. Subgroups of patients who may benefit from such efforts include individuals with high-risk but sub-maximal AUDIT-C scores, older patients, and patients who are seen at community-based outpatient clinics.