It was hypothesized that Involuntary Psychiatric Admissions are associated with the increased medical cost and mortality risk. The research framework of this study involved correlations among involuntary psychiatric admissions, medical costs, and mortality risk. To select individuals with similar attributes for research and control groups and to prevent heterogeneity between selection error and the baseline [18], this study performed 1:4 PSM for patients with mental illness who had involuntary and voluntary psychiatric admissions in terms of sex, age, comorbidity severity, insured amount, mental illness type, and year of diagnosis. The research group contained 181 patients with involuntary psychiatric admissions, and the control group consisted of 724 patients with voluntary psychiatric admissions (905 patients in total). The current study was reviewed and approved by the Research Ethics Committee at China Medical University and Hospital, Taichung, Taiwan, under no. CMUH105-REC3-016. The requirement of informed consent was waived by the ethics committee.

This study used the Longitudinal Health Insurance Database (LHID), which contains the claims data of 1 million beneficiaries randomly selected from all people insured by Taiwan’s National Health Insurance program. We obtained electronic data from the National Health Research Institutes with the authorization of the Department of Health. The LHID contains information on medical care for inpatient and outpatient visits for each beneficiary from 2002 to 2013. In accordance with the Taiwan Personal Information Protection Act, the identities of insured people were recoded by randomization before data were released to researchers.

The research population consisted of patients with mental illness classified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) [19] with diagnostic codes: 290.xx-319.xx from 2002 to 2013. Because patients receiving diagnoses of mental illness in 2002 could not be validated as having first-time diagnoses of mental illness, all cases diagnosed in 2002 were excluded. In addition, because minors are a vulnerable group, to protect their rights, this study retained only patients older than 20 years as research patients.

Research variables were extracted from the database content, and most variables were obtained from the first data entries of patients during the research period as the determination basis, such as mental illness type, sex, age, insured amount, institution level, institution ownership type, primary physician seniority, insured branch, and degree of urbanization. The remaining variables were obtained from all entries input during the research period including involuntary psychiatric admissions, whether patients had multiple mental illnesses, comorbidity severity, drug use, death, and medical costs. The first entry of mental illness diagnosed between 2002 and 2013 was adopted as patients’ type of mental illness. The mental illness diagnostic codes were determined by referencing the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) [20]. In reference [19] to, comorbidity severity (Charlson comorbidity index, CCI) was grouped.

All statistical analyses were performed using SAS version 9.4 (Statistical Analysis System, SAS Institute Inc., Cary, NC, USA). The significance level of 0.05 was determined while p-value less than 0.05 was considered statistically significant. Besides, SPSS 23.0 (IBM Corp., Armonk, NY, USA) was adopted as a drawing tool of survival analysis. A chi-square independent test χ² was adopted to test the independence between independent variables, specifically the chrematistics of patients with mental illness (including characteristics of patient health, demographics, medical caregivers, and regions) and dependent variables (death, total medical costs, and average annual medical cost per person). A general linear model (GLM) was used to perform a multivariate analysis to compare the least squares (LS) means of independent variables affecting the average annual medical cost per person (patient receiving care). Since this study considered multiple independent variables, the Cox proportional hazards model was used to determine the relationship between independent variables and death, in order to show the status of mortality risk among different variables.

The life expectancy of patients with mental illness is shorter than that of an average person, compared to female patients with psychiatric disorders, male patients with psychiatric disorders likely demonstrate more unfavorable behaviors, insufficient health care use, and lower medical compliance. In addition, the average YPLL in men with psychiatric disorders are longer [21-26], and the difference in the mortality risk of patients with and without mental illness has gradually widened [27] because of the increased life expectancy of the general public [21,28]. This study demonstrated that other high-risk mortality factors of patients with mental illness including male, age ≥65 years, insured amount ≥$22,801, regional-level hospitals, primary caregiver seniority of 6-10 years, and northern insured branch. A chi-square test was performed to analyze the correlation between involuntary psychiatric admissions and death for the matched samples of patients.The sample of this study are patients with severe mental illness, and they have more life lost than those with a general mental illness. The patients with involuntary psychiatric admissions had a shorter life expectancy but did not have a significantly different mortality risk compared with patients with voluntary admissions. The medical conditions of the patients were effectively controlled during hospitalization, but patients were likely to lack health awareness and have medical attention interruptions after hospital discharge, which resulted in involuntary psychiatric readmissions that indirectly contributed to an increased mortality risk. Therefore, health authorities should use post discharge care and periodic tracking to strengthen home medical care services [29] after patients who were admitted involuntarily are discharged from the hospital to prevent the aggravation of medical conditions and death [30].

The analysis results in this study demonstrated that patients with involuntary psychiatric admissions had significantly higher medical costs than those with general psychiatric illness. This finding coincides with the results of an international study [13]. The average annual medical costs of patients with involuntary psychiatric admissions was NT$115,654, which was 5.8 times higher than that of patients with voluntary psychiatric admissions. Thus, the medical cost burden for patients with involuntary psychiatric admissions was significantly higher than that of patients with voluntary psychiatric admissions. Regarding mental illness type, the average annual medical cost per person for patients with schizophrenia was the highest at NT$93,492, whereas the medical costs for patients with drug abuse were the lowest. Some studies have indicated that the length of time required to survive the acute phase of a disease varies by mental illness. In particular, patients with schizophrenia required the longest recovery and hospitalization time [31], leading to higher medical costs such as medication, treatment, and ward fees.

Involuntary psychiatric admissions fall under the need and factors of health services utilization in Andersen’s behavioral model [32]. Patients have higher readmission rates and longer hospitalization times. They may also have higher hospitalization and treatment needs, which likely increase higher costs of drug administration and medical condition control.

Organic mental disorders accounted for the highest mortality risk in this study, whereas other mental illnesses accounted for the lowest risk. Schizophrenia accounted for the highest medical costs, whereas substance abuse accounted for the lowest costs. In this study, other factors related to the mortality risk of patients with mental illness were analyzed to determine their high-risk mortality factors, such as male, old age, high income, regional-level hospital, and lower physician seniority, which can serve as a reference for relevant government units during policy formulation.

In this study, secondary data were collected from the National Health Insurance Database of the National Health Research Institutes. Therefore, only available data patterns were explored. Because of the database limitation in this study, only medical expenses and drug use among patients with mental illness were analyzed. Follow-up research should include variables for education level, work status, and genetic history to further investigate the basic characteristics of patients with mental illness and enhance the research. This study demonstrated that some patients with involuntary psychiatric admissions were likely to be readmitted. The medical conditions of these patients were likely to be recurrent and uncontrollable. Follow-up studies may consider the factors contributing to multiple involuntary psychiatric admissions to further explore the effect of mortality risk and medical costs to enhance research completeness.

In conclusion, severe and complex conditions are characteristic of patients with involuntary psychiatric admissions. This study demonstrated no significant difference in mortality risk between patients with voluntary and involuntary psychiatric admissions. However, average annual per-person medical costs were significantly higher for patients with involuntary psychiatric admissions than for patients with voluntary psychiatric admissions. Thus, controlling their medical conditions requires more resources. Furthermore, personal, family, and social costs are a substantial burden. The government should formulate relevant health policies, engage in active planning regarding high medical costs, and plan relevant health welfare. The results in this study show that compared to voluntarily admitted patients, the potential life lost (YPLL) may be slightly longer. On the other hand, the research results also show that the average survival time, from a confirmed diagnosis of psychiatric disorders to death, of involuntarily admitted patients is 5.15 years, which is longer compared to voluntarily admitted patients. The sample of this study are patients with severe mental illness, and they have more life lost than those with a general mental illness. Treatment may effectively stabilize their condition and reduce mortality, possibly indicating the effectiveness of involuntary treatments. Compared with disease prevention plans intended only to treat diseases, cost effectiveness in disease prevention exerts a greater influence on people. Early intervention in medical institutions for patients with involuntary psychiatric admissions is recommended to provide the most effective medical care. Priority low-cost interventions targeting patients with organic mental disorders and drug abuse should be implemented to improve the quality of psychiatric care and the financial balance of the National Health Insurance program by extending integrative care in homes, communities, and medical institutions.