Medication Dosage Impact on Mortality in Old-Age Individuals with Schizophrenia: A National Cohort Study

Abstract

As the prevalence of old-age individuals with schizophrenia (OAS) increases in a society undergoing demographic aging, the exploration of medication choices becomes increasingly crucial. Due to the current scarcity of literature on OAS, this study seeks to examine how the utilization and cumulative dosages of psychotropic medications influence both overall and cause-specific mortality risks within this population. A national cohort of 6433 individuals diagnosed with OAS was followed up for 5 years. This study involved comparing the mortality rates associated with low, moderate, and high dosages of antipsychotics, antidepressants, mood stabilizers, and sedative/hypnotic drugs against the ‘no exposure’ category, based on individual dosages. Cox regression was employed for survival analyses to compare overall mortality and specific-cause mortality across various dosage groups. The exposure variable examined was the dosage of a specific psychotropic medication. Covariates were adjusted accordingly. The analysis revealed that patients on low/moderate antipsychotic doses had improved survival compared to non-exposed individuals. Moderate antipsychotic use corresponded to reduced cardiovascular disease mortality risk. Similarly, those exposed to antidepressants had enhanced survival in low and moderate doses. Sedative-hypnotic exposure was linked to decreased mortality risk in low doses. This study observed that low/moderate antipsychotic doses in older adults with schizophrenia were associated with decreased all-cause mortality, emphasizing the significance of precise medication selection and dosing. It underscores the need for vigilant polypharmacy management and tailored medication strategies in addressing the complexities of treating OAS.