Healthcare resource utilization and direct medical costs in patients with dual diagnosis in Italy

Objectives This study is aimed at analyzing the patterns of care and annual costs of services in patients with dual diagnosis treated in an Italian Mental Health and Pathological Dependency Department (MH-PDD). Methods In this retrospective prevalence-based study, healthcare accesses of 331 patients with dual diagnosis being treated at the MH-PDD were obtained through a linkage of 7 administrative databases (Tab. I). All adult patients with at least one contact with the MH-PDD are recorded in the database, which includes demographic characteristics, the ICD-9-CM diagnosis and information on each type of service provided. The ICD-9-CM are grouped into diagnostic categories, defined in Table II. Costs were assigned using different drivers and cost objects (national, regional tariffs and ad hoc estimated MH costs). Results The study population consisted of 331 patients with a diagnosis of substance abuse and a mental health disorder who had at least one contact with the MH-PDD in 2013. Patients were 68% male, with a mean age of 45 years and 93% Italian (Tab. III). A large proportion (n = 228, 68.6%) had a > 2 year duration of contact with MH-PDD. The substance of abuse or dependence was alcohol in the large majority (n = 196, 59.2%), followed by drugs (n = 99, 29.9%) and other substances (n = 16, 4.8%). Among the MH-PDD services that patients received, psychiatric-clinical treatment and initial assessment/reassessment and were the most frequent interventions, while vocational training, psychosocial rehabilitation and day center services were uncommon (Tab. IV). Total MH-PDD costs were 867,080€ and costs per patient ranged from 25€ (three psychiatric follow-up visits) to 239,125€ in one outlier patient with psychosis and alcohol use disorder, who received 1,100 MH services and 22 home visits (Tab. V). The median cost was 279€ and the mean cost 2,620€. The amount of non-MH-PDD costs almost equaled that of MH-PDD costs, and was largely ascribable to hospitalization in psychiatric and non-psychiatric wards (Fig. 1). Overall costs per patient ranged from 45€ (first MH-PDD assessment) to €239,287 (the same outlier patient, with 1,100 MH services, 22 home visits and 4 specialty services). Median cost was 1,423€, mean cost 5.381€ and the overall total was 1,780,958€. Classification of patients in cost tertiles revealed that one third of patients accounted for 88.1% of overall costs (Fig. 2). The costs borne by the MH-PDD increased from the first to the third tertile while the vice versa was true for non-MH-PDD costs. Median costs by psychiatric diagnosis ranged from 205€ for other mental disorders to 2,085€ for dementia (Tab. V, Fig. 3). Conclusions An integrated healthcare system based on outpatient management of patients with substance abuse/dependence costs less than other countries with different healthcare systems. In the absence of outcome data, cost-effectiveness studies are warranted.