Relating Spontaneously Reported Extrapyramidal Adverse Events to Movement Disorder Rating Scales

While antipsychotic-induced extrapyramidal symptoms (EPS) and akathisia remain important concerns in the treatment of patients with schizophrenia, the relationship between movement disorder rating scales and spontaneously reported EPS-related adverse events (EPS-AEs) remains unexplored.

Data from four randomized, placebo- and haloperidol-controlled ziprasidone trials were analyzed to examine the relationship between spontaneously reported EPS-AEs with the Simpson Angus Scale (SAS) and Barnes Akathisia Rating Scale (BARS). Categorical summaries were created for each treatment group to show the frequencies of subjects with EPS-AEs in each of the SAS and BARS categories at weeks 1, 3, and 6, and agreement between ratings was quantified by means of weighted kappa (κ).

In general, we found greater frequencies of EPS-AEs with increasing severity of the SAS and BARS scores. The EPS-AEs reported with a "none" SAS score ranged from 0 to 22.2%, with a "mild" SAS score from 3.3 to 29.0%, and with a "moderate" SAS score from 0 to 100%. No subjects in any treatment group reported "severe" SAS scores or corresponding EPS-AEs. Agreement between SAS scores and EPS-AEs was poor for ziprasidone and placebo (κ < 0.2) and only slightly better for haloperidol. The EPS-AEs reported with "non questionable" BARS scores ranged from 1.9 to 9.8%, with "mild moderate" BARS scores from 12.8 to 54.6%, and with "marked severe" scores from 0 to 100%. Agreement was modest for ziprasidone and placebo (κ < 0.4) and moderate for haloperidol (κ < 0.6).

These findings may reflect either underreporting of AEs by investigators and subjects or erroneous rating scale evaluations.