ABSTRACT
OBJECTIVE: The aim of the study is to explore the incidence and the risks associated with major osteoporotic fractures, all-cause mortality with osteoporotic fractures and the effect of the psychiatric drug exposure in patients with schizophrenia during a 10-year follow-up period. METHODS: Two nationwide cohorts were selected from the Taiwan National Health Insurance Research Database (NHIRD) consisting of 30,335 patients with schizophrenia (age ≥ 40 years) and 121,340 age- and sex-matched control participants without schizophrenia. The psychiatric proportion of days covered (PDC) is an indicator of the intensity of drug exposure in patients with schizophrenia. The incidence and risk factors of major osteoporotic fractures were calculated for both cohorts. Additionally, the patient survival rate after major osteoporotic fractures was also calculated. RESULTS: During a 10-year follow-up period, 1677 (5.53%) schizophrenia and 4257 (3.51%) control subjects had major osteoporotic fractures (P < 0.001). The schizophrenia patients with a PDC > 0.1 showed a significantly higher incidence of major osteoporotic fractures than did the non-schizophrenia controls; however, those with a psychiatric PDC ≤ 0.1 did not. After adjustment, the psychiatric PDC was significantly and independently associated with the risk of major osteoporotic fractures except some medical morbidities but the schizophrenia diagnosis was not. In addition, among all 5934 patients with major osteoporotic fracture, the adjusted mortality hazard ratio for psychiatric PDC was 1.92 (95% CI = 1.63-2.26). CONCLUSIONS: Patients with schizophrenia are at a higher risk for major osteoporotic fractures than the general population and also have a higher mortality rate due to major osteoporotic fractures. These findings may be caused by psychiatric drug use rather than schizophrenia, which suggests that directions can be taken in future studies.
