10-year Trends in Diagnostic Stability and Distribution among Psychiatric Inpatients in a General Hospital in China: A Retrospective Study

Abstract Background: Diagnoses of mental disorders are complex and their validity is realized by diagnostic stabilities. We aimed to evaluate the short-term and long-term stability of mental disorders diagnosed over the past decade in the psychiatry department of a general hospital, determine factors associated with consistency, and assess the distribution of diseases in the sample. Methods: A total of 20,359 psychiatric inpatients were included in this retrospective study from June 2011 to December 2020. The short-term diagnostic consistency was evaluated by comparing their first admission and discharge diagnoses. Readmission patients' first and last discharge diagnoses were also compared to analyze the relatively long-term diagnostic stability. Demographic and clinical characteristics were analyzed to identify predictors of diagnostic discrepancy during hospitalization. Results: From 2011-2020, for all psychiatric inpatients, the average length of stay decreased from 22 days to 17 days. The hospitalization rate decreased from 42.4% to 20.7% for schizophrenia and grew from 13.8% to 25.5% for depression. Diagnoses were retained by 92.6% of patients at their first discharge diagnosis, ranging from 100% for disorders of psychological development to 16.3% for unspecified mental disorders. Above one-third of diagnostic conversions were to bipolar disorder in patients having inconsistent diagnoses. However, among rehospitalizations, the diagnostic stability notably dropped to 71.3%. For rehospitalizations, mood disorders and schizophrenia spectrum disorders were relatively stable diagnoses categories, with 72.7%-76.7% of patients receiving the same diagnosis, although results of specified diagnoses within these categories ranged from 5.9% to 91%. Except for mood disorders and schizophrenia spectrum disorders, the diagnoses of all other categories were below 70%. Besides, long lengths of hospitalization and old age were associated with the diagnosis alterations. Conclusion: For first hospitalizations, even though the diagnosis was stable in the short term, longitudinal follow-up and integration of multiple aspects of information are essential for accurate diagnosis.