Background
Patients with severe mental illness (SMI) have a reduced life expectancy of one to two decades as compared to the general population, with most years of life lost due to somatic diseases. Most previous studies on disorders constituting SMI, e.g. schizophrenia and bipolar disorder, have investigated the disorders separately and hence not compared the disorders in terms of mortality rates relative to the background population.
Methods
A register-based cohort study including the entire Danish population comparing mortality rates relative to the background population, controlling for age and sex, i.e. standardized mortality ratios (SMRs) in patients diagnosed with schizophrenia with those in patients diagnosed with bipolar disorder, during the study period from 1995 to 2014.
Results
The SMR of patients with SMI was significantly higher than one for each calendar year in the study period with an overall SMR of 4.58, 95% CI (4.48–4.69) in patients diagnosed with schizophrenia (n = 38,500) and of 2.57 (95% CI 2.49–2.65) in patients diagnosed with bipolar disorder (n = 23,092). When investigating time trends in SMR for schizophrenia and for bipolar disorder, respectively, an increase in SMR over time was shown with a mean increase of 0.03 per year for schizophrenia and 0.02 for bipolar disorder (p < 0.01 for both disorders). The ratio between SMR for schizophrenia and SMR for bipolar disorder for each calendar year over the study period was constant (p = 0.756).
Conclusions
Increasing SMRs over the last 20 years were found for both patients diagnosed with bipolar disorder and patients diagnosed with schizophrenia. Despite clear differences between the two disorders regarding SMRs, the increases in SMR over time were similar, which could suggest similar underlying factors influencing mortality rates in both disorders.
The mortality gap between patients with bipolar disorder and the general Danish population has widened over the past two decades, which is a cause for concern, although reasons for the increasing mortality gap are unknown.
Background
Coronary heart disease (CHD) is a major cause of increased mortality rates in patients with schizophrenia. Moreover, coronary artery calcium (CAC) score is associated with CHD. We hypothesized that patients with schizophrenia have more CAC than the general population and aimed to investigate the CAC score in patients with schizophrenia compared to norms based on the general population. Additionally, this study investigated if age, sex, diabetes, dyslipidemia and smoking were associated with the CAC score.
Methods
In a cross-sectional study, 163 patients with schizophrenia underwent cardiac computed tomography, and the CAC score was measured and compared to norms by classifying the CAC scores in relation to the age- and gender matched norm 50th, 75th and 90th percentiles. Logistic and linear regression were carried out to investigate explanatory variables for the presence and extent of CAC, respectively.
Results
A total of 127 (77.9%) patients had a CAC score below or equal to the matched 50th, 20 (12.3%) above the 75th and nine (5.5%) above the 90th percentile. Male sex (P < 0.05), age (P < 0.001) and smoking (P < 0.05) were associated with the presence of CAC while age (P < 0.001) and diabetes (P < 0.01) were associated with the extent of CAC.
Conclusions
The amount of CAC in patients with schizophrenia follows norm percentiles, and variables associated with the CAC score are similar in patients with schizophrenia and the general population. These findings indicate that the CAC score may not be sufficient to detect the risk of CHD in patients with schizophrenia. Future studies should explore other measures of subclinical CHD, including measures of peripheral atherosclerosis or cardiac autonomic neuropathy to improve early detection and intervention.
Trial registration
ClinicalTrials.gov Identifier: NCT02885792, September 1, 2016.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.