Patterns of Serum Prolactin Elevation Associated with Nine Second-Generation Antipsychotics in a Large Cohort of Patients with Schizophrenia.

Background: Prolactin elevation associated with antipsychotic use significantly affects medication adherence and long-term treatment outcomes in patients with schizophrenia. The currently available data are insufficient to guide the monitoring and management of elevated prolactin levels in patients on antipsychotic medications. This study aimed to explore the patterns of prolactin level elevation associated with nine second-generation antipsychotics (SGAs) in a real-world setting and compare the associated risks.

Methods: This retrospective cohort study utilized data from the inpatient electronic medical records of a large mental health center in China from 2007 to 2019. The study included patients diagnosed with schizophrenia (ICD-10 criteria) who received SGA therapy and whose serum prolactin levels were measured. Exposures were the use of nine specific SGAs (amisulpride, risperidone, paliperidone, ziprasidone, olanzapine, perospirone, quetiapine, clozapine, or aripiprazole), including polytherapy and monotherapy. The primary outcome was incident prolactin elevation in patients during hospitalization. An adjusted stratified Cox proportional hazards regression analysis was used to compare the hazard ratios (HRs) of prolactin level elevation across the nine SGAs. In addition, a dose-response analysis of these SGAs was conducted using the defined daily dose (DDD) method. Dose categories were as follows: < 0.6 DDDs/day (low dose), 0.6 to < 1.1 DDDs/day (medium dose), and ≥ 1.1 DDDs/day (high dose).

Results: This study included 6489 patients with schizophrenia (mean [SD] age, 35.1 [14.2] years; 3396 males [52.3%]). Compared with the nonexposure, amisulpride (HR 2.76, 95% confidence interval [CI] 2.12-3.59), risperidone (HR 2.70, 95% CI 2.30-3.16), paliperidone (HR 1.84, 95% CI 1.37-2.46), and ziprasidone (HR 1.36, 95% CI 1.06-1.76) were associated with the highest risk of prolactin elevation. In contrast, quetiapine (HR 0.73, 95% CI 0.61-0.87), clozapine (HR 0.59, 95% CI 0.46-0.76), and aripiprazole (HR 0.30, 95% CI 0.23-0.37) were associated with the lowest risk. Amisulpride posed the highest risk among male patients, whereas risperidone posed the highest risk among female patients. Different types of dose-response associations were detected in seven SGAs.

Conclusion: This cohort study, conducted in an inpatient setting, identified different risks of prolactin elevation associated with SGAs, along with their dose-response curves. Sex and age must be considered when prolactin elevation is analyzed in patients with schizophrenia who are treated with SGAs.

Trial Registration: ClinicalTrials.gov identifier: NCT04002258.