Risk Factors for Tardive Dyskinesia in Patients Taking Antipsychotics

Investigators identified several risk factors for tardive dyskinesia (TD) in patients taking antipsychotics, including age, schizophrenia diagnosis, high antipsychotic dosage, and comorbid psychiatric disorders, according to study data published in BMC Neurology.

Investigators conducted a retrospective cohort study with data abstracted from a Medicaid claims database. The database comprised Medicaid claims from six US states between 1997 and 2016. Adult patients with schizophrenia, major depressive disorder, or bipolar disorder taking antipsychotic medications were selected for inclusion in the study. Patients who developed TD within one year after the first observed antipsychotics claim were compared with patients who did not develop TD. Univariate Cox analyses were performed to identify TD risk factors, expressed as hazard ratios (HRs). The least absolute shrinkage and selection operator regression method was then used to develop a Cox proportional hazards model for predicting TD diagnosis.  

The study cohort comprised 189,415 eligible patients of mean age 42.8 years, 38.1% men. The average daily dose of antipsychotic medication was 220 mg of chlorpromazine equivalent, and the majority of patients (86.7%) were prescribed a second-generation antipsychotic at index date. Of 151,280 patients with at least one year of continuous eligibility after the index date, 381 (0.3%). developed TD. The multivariate Cox prediction model was well-calibrated (P =.32 for Hosmer-Lemeshow goodness-of-fit test) and displayed acceptable concordance (70.6%), or ability to discriminate between low and high-risk patients. Per this model, the following patient characteristics were significantly associated with increased risk for TD: age (HR, 1.04; P <.001); diagnosis of schizophrenia vs bipolar disorder (HR, 1.99; P <.001); antipsychotic dosage (up to 100 mg/day of chlorpromazine equivalent; HR, 1.65; P <.01); and comorbid bipolar and related disorders (HR, 1.39; P <.01).

Additional potential risk factors included history of extrapyramidal symptoms (HR, 1.35; P =.33), diabetes (HR, 1.13; P =.14), and other movement disorders including parkinsonism (HR, 1.43; P =.55), bradykinesia (HR, 1.44; P =.25), tremors (HR, 2.12; P =.06), and myoclonus (HR, 2.33; P =.25). Compared with first-generation antipsychotics, use of second-generation antipsychotics was associated with a nominally lower risk for TD (HR, 0.85; P =.09).

As the present study population was limited to patients in the Medicaid database, results must be extrapolated with care.

“This study identified factors associated with development of TD among patients taking antipsychotics. The prediction model described herein can enable physicians to better monitor patients at high risk for TD and recommend appropriate treatment plans to help maintain quality of life,” investigators concluded.

Reference

Patterson-Lomba O, Ayyagari R, Carroll B. Risk assessment and prediction of TD incidence in psychiatric patients taking concomitant antipsychotics: a retrospective data analysis. BMC Neurol. 2019;19(1):174.