Risk factors for sudden cardiac death among patients with schizophrenia

Introduction: Patients with schizophrenia suffer from excessive premature mortality, and sudden cardiac death (SCD) is receiving growing attention as a potential cause. Aim: The present study investigated the incidence of SCD and its risk factors in a large schizophrenia cohort. Methods: We enrolled a consecutive series of 8264 patients diagnosed with schizophrenia (according to DSM-III-R and DSM-IV criteria) who were admitted to a psychiatric center in northern Taiwan from January 1, 1985 through December 31, 2008. By linking with national mortality database, 64 cases of SCD were identified. The standardized mortality ratio (SMR) for SCD was estimated. The cases were matched with controls randomly selected using risk-set sampling in a 1:2 ratio. A standardized chart review process was used to collect socio-demographic and clinical characteristics and the prescribed drugs for each study subject. Multivariate conditional logistic regression analysis was used to identify correlates of SCD at the index admission and the latest admission. Results: The SMR for SCD was 4.5. For the clinical profiles at the index admission, physical disease (adjusted risk ratio [aRR] = 2.91, P<. .01) and aggressive behaviors (aRR = 3.99, P<. .01) were associated with the risk of SCD. Regarding the latest admission, electrocardiographic abnormalities (aRR = 5.46, P<. .05) and administration of first-generation antipsychotics (aRR = 5.13, P<. .01) elevated the risk for SCD. Consistently, aggressive behaviors (aRR = 3.26, P<. .05) were associated with increased risk as well. Conclusions: Apart from cardiovascular profiles and antipsychotics, physical aggression is a crucial risk factor that deserves ongoing work for clarifying the mechanisms mediating SCD in schizophrenia.