Association of mental disorders with costs of somatic admissions in France

Mentally ill patients have worse health outcomes when they suffer from somatic conditions compared to other patients. The objective of this study was to assess the association of mental illness with hospital inpatient costs for somatic reasons.

All adult inpatient stays for somatic reasons in acute care hospitals between 2009 and 2013 were included using French exhaustive hospital discharge databases. Total inpatient costs were calculated from the all-payer perspective and compared in patients with and without a mental disorder. Only patients who had been admitted at least once for a mental disorder (either full-time or part-time) were considered to be mentally ill in this study. Generalized linear models with and without interaction terms studied the factors associated with hospital inpatient costs.

17,728,424 patients corresponding to 37,458,810 admissions were included. 1,163,972 patients (6.57%) were identified as having a mental illness. A previous full-time or part-time admission for a mental disorder significantly increased hospital inpatient costs (+32.64%, 95%CI=1.3243-1.3284). Interaction terms found an increased impact of mental disorders on costs in patients with low socio-economic status, as well as in men, patients aged between 45 and 60, and patients with a cardiovascular disease or diabetes.

Mentally ill patients have higher hospital costs than non-mentally ill patients. Improving curative and preventive treatments in those patients could improve their health and decrease the burden on healthcare systems.