PURPOSE: Almost half of all patients diagnosed with schizophrenia have a history of substance abuse (SA). However, data on treatment of schizophrenia with paliperidone palmitate (PP) among patients with comorbid SA are limited. The objective of this study was to compare all-cause and SA-related health care resource utilization and costs in veterans with schizophrenia and co-occurring SA who were treated with PP versus oral atypical antipsychotics (OAAs). METHODS: Veterans Health Administration electronic health record data were used to conduct a retrospective longitudinal study in veterans with schizophrenia who initiated PP or OAA between January 1, 2010 and June 30, 2016, had ≥12 months of enrollment before treatment initiation (baseline), were diagnosed with SA, and had ≥1 Global Assessment of Functioning score during baseline. Differences in baseline characteristics were adjusted for using inverse probability of treatment weighting. Adjusted cost differences and incidence rate ratios (IRR) for the association between PP versus OAA and all-cause and SA-related health care costs and health care resource utilization in the 12 months after treatment initiation were estimated with corresponding 95% CIs using weighted linear and Poisson regression models, respectively. FINDINGS: Of 6872 veterans in the study, 1684 (25%) and 5188 (75%) were treated with PP and OAA, respectively. After adjustment, PP was associated with fewer all-cause inpatient (IRR = 0.88; 95% CI, 0.85 to 0.90), mental health-related inpatient (IRR = 0.88; 95% CI, 0.85 to 0.91), and long-term care stays (IRR = 0.53; 95% CI, 0.44 to 0.64), but more frequent mental health intensive case management visits (IRR = 1.51; 95% CI, 1.49 to 1.53) compared with OAA (all P < 0.001). Similarly, PP was associated with significantly lower rates of SA-related inpatient stays (IRR = 0.80; 95% CI, 0.77 to 0.83), mental health stays (IRR = 0.85; 95% CI, 0.82 to 0.88), long-term care stays (IRR = 0.22; 95% CI, 0.15 to 0.32), and outpatient visits (IRR = 0.78; 95% CI, 0.77 to 0.79) than OAA (all P < 0.001). Relative to OAA, patients treated with PP also had lower mean annual all-cause (cost difference = -$10,473; 95% CI, -$17,827 to -$3491) and SA-related (cost difference = -$8457; 95% CI, -$12,710 to -$3638) medical costs (all P < 0.001). IMPLICATIONS: PP was associated with significant total medical cost savings resulting from fewer hospitalizations and lower rates of SA-related health care resource utilization compared with OAA in patients with schizophrenia and comorbid SA. Thus, PP appears to be a valuable treatment option for patients in this subpopulation.
PURPOSE: Almost half of all patients diagnosed with schizophrenia have a history of substance abuse (SA). However, data on treatment of schizophrenia with paliperidone palmitate (PP) among patients with comorbid SA are limited. The objective of this study was to compare all-cause and SA-related health care resource utilization and costs in veterans with schizophrenia and co-occurring SA who were treated with PP versus oral atypical antipsychotics (OAAs). METHODS: Veterans Health Administration electronic health record data were used to conduct a retrospective longitudinal study in veterans with schizophrenia who initiated PP or OAA between January 1, 2010 and June 30, 2016, had ≥12 months of enrollment before treatment initiation (baseline), were diagnosed with SA, and had ≥1 Global Assessment of Functioning score during baseline. Differences in baseline characteristics were adjusted for using inverse probability of treatment weighting. Adjusted cost differences and incidence rate ratios (IRR) for the association between PP versus OAA and all-cause and SA-related health care costs and health care resource utilization in the 12 months after treatment initiation were estimated with corresponding 95% CIs using weighted linear and Poisson regression models, respectively. FINDINGS: Of 6872 veterans in the study, 1684 (25%) and 5188 (75%) were treated with PP and OAA, respectively. After adjustment, PP was associated with fewer all-cause inpatient (IRR = 0.88; 95% CI, 0.85 to 0.90), mental health-related inpatient (IRR = 0.88; 95% CI, 0.85 to 0.91), and long-term care stays (IRR = 0.53; 95% CI, 0.44 to 0.64), but more frequent mental health intensive case management visits (IRR = 1.51; 95% CI, 1.49 to 1.53) compared with OAA (all P < 0.001). Similarly, PP was associated with significantly lower rates of SA-related inpatient stays (IRR = 0.80; 95% CI, 0.77 to 0.83), mental health stays (IRR = 0.85; 95% CI, 0.82 to 0.88), long-term care stays (IRR = 0.22; 95% CI, 0.15 to 0.32), and outpatient visits (IRR = 0.78; 95% CI, 0.77 to 0.79) than OAA (all P < 0.001). Relative to OAA, patients treated with PP also had lower mean annual all-cause (cost difference = -$10,473; 95% CI, -$17,827 to -$3491) and SA-related (cost difference = -$8457; 95% CI, -$12,710 to -$3638) medical costs (all P < 0.001). IMPLICATIONS: PP was associated with significant total medical cost savings resulting from fewer hospitalizations and lower rates of SA-related health care resource utilization compared with OAA in patients with schizophrenia and comorbid SA. Thus, PP appears to be a valuable treatment option for patients in this subpopulation.