[Cost of psychiatric patients by disability type].
OBJECTIVE: The study of the relation between treatment costs and disability of psychiatric patient groups. DESIGN: Perspective assessment of costs and disability of 1371 adult psychiatric patients in charge at two Operative Psychiatric Units (OPU), followed during an average period of 9 months. Data are related to all OPU's psychiatric services, including ambulatory, full or half-residential and psychiatric departments of acute hospital services. SETTING: OPUs of Magenta (MI) and Desio (MI). METHOD: The disability level has been measured by Health of the Nation Outcome Scales (HoNOS) filled in at the inclusion of the patient in the study and every three-months on average thereafter. Besides other HoNOSs have been filled in both at admission and discharge from psychiatric departments of acute hospitals, Residential Centres of psychiatric Therapies and Rehabilitation and Guarded Communities. All patients have been grouped using the main psychiatric diagnosis (first digit ICD-10) and the maximum disability level shown in the whole period of the study. Direct costs of publicly financed psychiatric services have only been considered. Their attribution to each patient has been made applying standard costs or tariffs (diagnostic procedures) to the data perspectively collected by the regional Register and a purposely designed protocol. RESULTS: Total cost of 1371 patients has been 9771.1 million lire with a cost per patient of 7,127,000 lire (sd 19,499,000) and a cost per "day in charge" of 27,172 lire (sd 68,358). The cost per day has been found unrelated with the length of observed time frame. At the inclusion the mean level of disability has been 4.26 points (sd 3.73) and 3.19 points (sd 3.26) at the end of the study. Its value, measured at maximum level shown by each problem in the whole period of study, has been 6.00 points (sd 4.64). Disability and treatment cost of each patient did result directly related (r = 0.626, p = 0.0001). All patients have been grouped in 12 classes with a significant (p = 0.0001) overall difference on both their disability level and treatment cost. CONCLUSIONS: All adult psychiatric patients could be grouped in disability related classes which sometimes have also a different treatment cost. A study on a greater number of patients is needed to confirm these results. It may also provide a more reliable basis for a new financing system of psychiatric services.