(SLA-061) Antipsychotic-Induced Weight Gain (AIWG) Among Patients Attending a Psychiatric Clinic at the Lagos State University Teaching Hospital (LASUTH)

Background: Common adverse effects (AEs) of antipsychotics include extrapyramidal symptoms, dry mouth, sedation, agitation, blurred vision, and weight gain. Of these AEs, weight gain remains the most concerning and can negatively affect the physical health, psychological well-being, and treatment outcomes of patients. Weight gain puts patients at risk of cardiovascular diseases, diabetes and metabolic disorders. There is a dearth of information on the occurrence of AIWG among adult and pediatric populations in sub-Saharan Africa, hence this study.

Objectives: This study aimed to describe antipsychotic usage patterns and determine the prevalence of antipsychotic-induced weight gain (AIWG) among patients attending a psychiatric clinic at the Lagos State University Teaching Hospital (LASUTH).

Methods: This retrospective study included adults (≥20 years) diagnosed with psychosis at LASUTH's outpatient psychiatric clinic between January 2022 and December 2023. Patients were identified from the attendance register, and case files were reviewed. Eligibility required age ≥20 years, no medical comorbidities (e.g., diabetes, hypertension, obesity, kidney disease), diagnosis and management at LASUTH during the study period, and antipsychotic use for ≥4 weeks. Data were extracted using a standardized form. Antipsychotic-induced weight gain (AIWG) was defined as ≥3 kg increase within ≥4 weeks, reported by the patient, guardian, or physician.

Results: This study included 100 eligible patients, with equal proportions of males and females. Their median (IQR) age was 36.2 (27.5-44.4) years, baseline weight 59.7 (52.2-72.1) kg, and weight gain 9.5 (6.0-15.0) kg over 1.0 (0.5-3) years. A total of 138 antipsychotics (7 types) were prescribed, with atypical antipsychotics being most common (96; 69.6%). Olanzapine (58; 42.0%) was the most prescribed, followed by risperidone (32; 23.2%) and chlorpromazine (18; 13.0%). Among 29 patients with neuropsychiatric comorbidities, depression (14; 48.3%) was most common, with escitalopram prescribed in 10 (34.5%) cases.
All patients experienced weight gain. Olanzapine alone or with risperidone and escitalopram led to the highest gain (11-28 kg, mean 22 kg) over 0.5-1.0 years. Risperidone with chlorpromazine/aripiprazole and diazepam caused 12-14 kg gain. A Wilcoxon signed-rank test confirmed a statistically significant increase in weight from baseline to follow-up (p < 0.0001).

Conclusions: The prevalence of AIWG is high among patients on antipsychotics at a psychiatric clinic in LASUTH and the atypical antipsychotic were the most culpable. Olanzapine used singly or in combination with other antipsychotic drugs was implicated in the highest weight gain similar to previous reports globally. The potential risk of cardiovascular diseases and diabetes, following excessive weight gain, would suggest a need for AIWG monitoring antipsychotic therapy.