Ningbo Schizophrenia Cohort (NSC)—a longitudinal ambispective cohort based on electronic health records: cohort profile

PURPOSE: Electronic health records (EHR) passively generate large datasets on real-world patient populations in easily retrievable form, allowing the cost-efficient and timely execution of epidemiological cohorts on a broad array of topics. However, EHR-based cohorts specialising in mental disorders have not yet been reported. Ningbo has made significant achievements in healthcare data management in China. This study, relying on the Ningbo Mental Health Information System and the Ningbo Regional Health Information Platform, has established the Ningbo Schizophrenia Cohort (NSC), providing an exemplary study for cohort studies on schizophrenia. PARTICIPANTS: This population-based ambispective cohort study included patients with schizophrenia aged 18-65 years at the time of diagnosis who were eligible for healthcare services in Ningbo, China. Participants were identified using the Ningbo Mental Health Information System between 1 January 2010, and 31 December 2023. Once an individual enters the NSC, they are followed up continuously until death or relocation. A total of 26 899 patients with schizophrenia are included in the NSC. FINDINGS TO DATE: Among 26 899 patients, 55.4% were female and 53.1% had less than 7 years of education. Until 31 December 2023, 4505 deaths occurred, and 97.83% of patients had at least one electronic medical record. The median age at diagnosis for non-survivors (median (IQR): 40 (29-51) years) was higher than that of survivors (median (IQR): 34 (26-45) years). FUTURE PLANS: The NSC will continue to collect longitudinal data to capture the full life cycle of schizophrenia, including pre-onset, diagnosis, follow-up, recovery or death. This will result in a continuous, complete and multidimensional EHR for patients with schizophrenia. Planned future research aims to generate new real-world evidence on the aetiology of schizophrenia, investigate comorbidities to facilitate co-management and develop predictive models for schizophrenia and related cardiovascular diseases. TRIAL REGISTRATION NUMBER: NCT06370793.