Health Care Resource Utilization and Cost Before Initial Schizophrenia Diagnosis

The management of schizophrenia, a chronic, multifaceted mental health condition, is associated with considerable health care resource utilization (HCRU) and costs. Current evidence indicates that a high-risk and costly prodromal period, during which patients are likely symptomatic, precedes diagnosis. Better characterization and disease management during this stage could help to improve patient outcomes.

To describe and compare HCRU and costs for up to 5 years before diagnosis in a cohort with schizophrenia versus a demographically matched cohort without schizophrenia in a commercially insured U.S.

This retrospective study identified newly diagnosed schizophrenia patients using enrollee claims in the HealthCore Integrated Research Database between January 1, 2007, and April 30, 2016. The index date was defined as the date of the first medical claim with a schizophrenia diagnosis code. Schizophrenia patients were directly matched (1:4) by age, sex, and region to comparators without schizophrenia who were assigned the same index dates as their matched schizophrenia counterparts. Observation periods were 0-12, 13-24, 25-36, 37-48, and 49-60 months before the index date. Outcomes included HCRU and costs for inpatient admissions, emergency room visits, outpatient care (office visits and other outpatient services), and medications. Means, standard deviations, medians, and 95% confidence intervals were calculated for continuous variables; relative frequencies and percentages were calculated for categorical variables. Cohorts were compared with t-tests for continuous variables and chi-square tests for categorical variables. Differences across cohorts were estimated with individual generalized linear models for each observation period, controlling for gender, age, geographic region of residence, health plan type and subscriber status, behavioral pre-index comorbidities and chronic comorbidities during the period before diagnosis.

6,732 schizophrenia patients were matched to 26,928 patients without schizophrenia. All-cause inpatient admissions were more prevalent among schizophrenia patients than their comparators for all time periods (49-60 months prediagnosis: 9% vs. 4%; 0-12 months prediagnosis: 33% vs. 4%). The schizophrenia cohort had higher adjusted all-cause per-patient per-month health care costs relative to comparators from the earliest period of 49-60 months prediagnosis ($557 [95% CI = 474-639] vs. $321 [95% CI = 288-355]) through 0-12 months prediagnosis ($1,058 [95% CI = 998-1,115] vs. $338 [95% CI = 320-355]). Behavioral health-related costs were different in each time period as were cost ratios (schizophrenia costs: comparator costs), which increased from 5.4 in the earliest period to 14.8 in the year before diagnosis.

Schizophrenia patients had higher all-cause and behavioral health-related HCRU and costs before diagnosis than matched controls. Costs increased from 5 years to 1 year prediagnosis for schizophrenia patients driven primarily by inpatient hospital stays and prescription drug costs, but remained stable for comparators. Additional research is needed for the development of predictive models to aid in the identification of high-risk patients.

This study was sponsored by Boehringer Ingelheim Pharmaceuticals. Barron is an employee of HealthCore, which received funding from Boehringer Ingelheim to conduct this study. Wallace and York were employed by HealthCore at time of this study. Isenberg is an employee of Anthem. Franchino-Elder, Sidovar, and Sand are employees of Boehringer Ingelheim.