SU1. Tardive Dyskinesia Prevalence in the Period of Second-Generation Antipsychotic Use: A Meta-Analysis

Background: Tardive dyskinesia (TD) rates with second-generation antipsychotic (SGA) treatment were estimated to be considerably lower than with first-generation antipsychotics (FGAs). As recent data have questioned this notion, we conducted a meta-analysis on contemporaneous TD prevalence. Methods: We conducted an electronic database search (January 1, 2000–September 30, 2015) without language restriction using (“tardive dyskinesia” OR tardive) AND (antipsychotic*) plus specific names of SGAs. Of 8895 hits, we screened 203 full-text articles for cross-sectional, rating scale-based TD rates during SGA, FGA, or FGA + SGA treatments. Forty-one studies were used for random-effects meta-analysis and meta-regression. Two authors independently extracted data on overall and antipsychotic class-wise TD rates and on TD moderators (mean age and percentage of males in study population, illness duration of study cohort, study region, percent of parkinsonism). Results: The global mean TD prevalence was 25.3% (95% CI = 22.7%–28.1%) across all 41 studies (N = 11 493, mean age = 42.8 y, male = 66.4%, schizophrenia-spectrum disorders = 77.1%). TD prevalence varied greatly: Rates were lower with current SGA treatment (20.7%; 95% CI = 16.6%–25.4%, N = 5103) vs current FGA treatment (30.0%; 95% CI = 26.4%–33.8%, N = 5062; Q = 9.17, P = .002). This difference remained significant after controlling for moderators: higher age (Z = 2.85, P = .004; k = 39) and region (k = 39; Asia vs Europe, Z = 1.55, P = .12; Asia lower than United States, Z = 2.6, P = .009; Asia lower than other regions, Z = 2.42, P = .015). Additional moderators of TD prevalence included longer illness duration (R2 = 0.15; P = .03; k = 21) and frequency of parkinsonism (R2 = 0.23, P = .017; k = 19). Particularly low TD prevalence (7.2%; k = 4) was found in the treatment arms with FGA-naive subjects, relative to SGA-treated cohorts with likely prior FGA exposure (P < .001; k = 28). Lower TD prevalence of SGA relative to FGA was also confirmed in the subgroup of studies reporting on ≥2 antipsychotic classes/combinations; for SGAs vs FGAs (risk ratio = 0.80; 95% CI = 0.67–0.95, Z = −2.55, P = .011) and FGA + SGA (risk ratio = 0.80, 95% CI = 0.71–0.90, Z = −3.56, P < .001). Reports on TD severity, provided by 10 studies, were of insufficient quality for meta-analysis. Conclusion: Rating scale-based TD remains highly prevalent with an advantage of SGAs over FGAs. However, TD severity was insufficiently reported to allow for a clinical interpretation. Reasons for the high geographical variation warrant future research.