The effect of schizophrenia on length of in-hospital stay and major adverse cardiac events following acute coronary syndrome in Denmark

Background: The relationship between schizophrenia and acute coronary syndrome (ACS) has already been established. This study aims to investigate the difference in length of in-hospital stay (LoS) between a population with schizophrenia and a psychiatric healthy control (PHC) population following admission for a first ACS. Methods: Data for this retrospective study was collected from three nationwide databases in Denmark; The Danish Civil Registration System, the National Patient register and the Danish Psychiatric Central Register. Patients diagnosed with a first ACS (unstable angina ICD-10 I20.0, NSTEMI ICD-10 I21.4 and STEMI ICD-10 I21.0-I21.3) between 2000–2014 were identified and screened for an additional diagnosis of narrow spectrum schizophrenia ICD-10 F20. The patients were matched 1:2 to a PHC population on gender, age and year of first ACS diagnosis. The LoS, as well as the effect of schizophrenia on major adverse cardiac events (MACE: stroke, reinfarction and all-cause mortality) was investigated using cox regression analyses. Results: A total of 1,572 patients were analysed (schizophrenia: n=524), 65.27% of the population were males and the mean age was 61.13 years. There was no difference in LoS (p>0.05) between the populations. Patients with schizophrenia had a higher prevalence of cardiac risk factors such as anemia and diabetes mellitus. Having schizophrenia had a significant effect on stroke (HR 1.47, 95% CI: 1.29–1.68)) and all-cause mortality rates (HR 2.69, 95% CI: 2.25–3.20). The results for the individual ACS diagnoses can be found in Table 1.