Nationwide analysis of medical utilization in people with severe mental illness receiving home care case management.

Aim: This nationwide study investigated the change in medical utilization of psychiatric home care case management (CM).

Methods: This nationwide study enrolled patients receiving CM (N = 10,274) from January 1, 1999 to December 31, 2010, from Taiwan's National Health Insurance Research Database. Through a 2-year mirror-image comparison weighted by the contributed person-time for each subject, we evaluated changes in medical utilization. Furthermore, a case-crossover analysis was used to verify the independent effect of CM in changing medical utilization by adjusting the time-variant variables between the pre-2-year (within 2 years before receiving CM) and post-2-year (within years after receiving CM) periods. The same methodology was applied for the subsequent 2-year comparison to assess the maintenance effect.

Results: Of the 10,274 patients receiving CM, 69.7% had schizophrenia. The results showed a chronological trend for the intervention of CM. The adjusted mirror-image analysis revealed a significant decrement of psychiatric and involuntary admissions after the intervention, and the utilization shifted toward psychiatric outpatient service. The case-crossover analysis with the adjustment of time-variant covariates confirmed the independent effect of CM on the changes of medical utilization. The comparable effect persisted after the next 2 years of intervention. However, CM showed no impact on lowering the admission rate for comorbid physical illnesses after the intervention.

Conclusions: The CM model can effectively reduce psychiatric hospitalization and involuntary admission frequency but has no effect on comorbid physical illnesses. Care models aimed at ameliorating physical problems in such patients are needed.