title: Validation of a claims-based antipsychotic polypharmacy measure.
abstract: Purpose Given the metabolic and neurologic side effects of antipsychotics and concerns about the increased risks associated with concomitant use, antipsychotic polypharmacy is a quality concern. This study assessed the operating characteristics of a Medicaid claims-based measure of antipsychotic polypharmacy. Methods A random sample from 10 public mental health clinics and 312 patients met criteria for this study. Medical record extractors were blind to measure status. We examined the prevalence, sensitivity, specificity, and positive predictive value (PPV) in Medicaid claims, testing nine different definitions of antipsychotic polypharmacy, including >14, >60, or >90 days concurrent use of ≥2 antipsychotic agents, each with allowable gaps of up to 0, 14, or 32 days in days' supply of antipsychotic medications. Results All Medicaid claims measure definitions tested had excellent specificity and PPV (>91%). Good to excellent sensitivity was dependent upon use of a 32-day gap allowance, particularly as duration of concurrent antipsychotic use increased. The proposed claims-based measure (90-day concurrent use of ≥2 or more antipsychotics, allowing for a 32-day gap) had excellent specificity (99.1%, 95%CI: 98.2-99.6) and PPV (90.9%, 95%CI: 83.1-95.7) with good sensitivity (79.4%, 95%CI: 70.4-86.6). The overall level of concordance between claims and medical record-based categorization of antipsychotic polypharmacy was high (96.4%, n = 301/312 clients, Cohen's K = 84.7, 95%CI: 75.9-93.5). Discrepant cases were reviewed, and implications are discussed. Conclusions Administrative claims data can be used to construct valid measures of antipsychotic polypharmacy.
authors.affiliation: New York State Office of Mental Health (NYSOMH), Albany, NY, USA; Department of Epidemiology and Biostatistics, State University of New York at Albany, School of Public Health, Rensselaer, NY, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Leckman-Westin
authors.forename: Edith
authors.initials: E
authors.lastname: Kealey
authors.forename: Nitin
authors.initials: N
authors.lastname: Gupta
authors.forename: Qingxian
authors.initials: Q
authors.lastname: Chen
authors.forename: Tobias
authors.initials: T
authors.lastname: Gerhard
authors.forename: Stephen
authors.initials: S
authors.lastname: Crystal
authors.forename: Mark
authors.initials: M
authors.lastname: Olfson
authors.forename: Molly
authors.initials: M
authors.lastname: Finnerty
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D002648:Child; D004363:Drug Utilization / Q000592:standards*; D006801:Humans; D007345:Insurance Claim Review / Q000592:standards*; D008297:Male; D008484:Medicaid / Q000592:standards*; D008875:Middle Aged; D019338:Polypharmacy; D014481:United States; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents
keywords: Medicaid; administrative data; antipsychotic polypharmacy; pharmacoepidemiology; positive predictive value; sensitivity