Secondary prevention of cardiovascular disease could significantly reduce cardiac mortality among patients with schizophrenia, yet is underused, a study published Oct. 24 has found.
The retrospective study, which included a Danish nationwide cohort of 105,018 patients with myocardial infarction, including 684 patients with schizophrenia, showed that individuals with schizophrenia who did not receive secondary cardioprotective treatment had a more than eight times higher mortality, compared with people in the general population who did receive treatment (hazard ratio, 8.78; 95% confidence interval, 4.37-17.64), Pirathiv Kugathasan and his associates reported in JAMA Psychiatry.
In contrast, the investigators found, patients with schizophrenia who received cardioprotective treatment had a 97% higher mortality (HR, 1.97; 95% CI, 1.25-310), compared with the treated general population, which was not statistically different from individuals in the general population who did not receive treatment (HR, 2.95; 95% CI, 2.62-3.32) after adjustment for baseline characteristics.
“Given the increased cardiovascular risk among patients with schizophrenia, we believe that the current findings support the use of intensive cardioprotective treatments in patients with schizophrenia,” reported Mr. Kugathasan, a PhD candidate in the department of psychiatry at Aalborg University Hospital in Denmark.
However, 7.8% of patients diagnosed with schizophrenia received no prescriptions for cardioprotective medications after a myocardial infarction, compared with 3.3% of the general population. They were significantly less likely than were individuals from the general population to receive a prescription for antiplatelets (84.9% vs. 91.8%), vitamin K antagonists (15.9% vs. 24.2%), beta-blockers (74.1% vs. 84.9%), ACE inhibitors (70.9% vs. 86.6%), and statins (72.2% vs. 87.3%).
The mortality rates were not significantly different between untreated patients with schizophrenia and untreated participants from the general population.
When the researchers examined the effects of different treatment types, they found that mortality rates were still higher in treated patients with schizophrenia, compared with treated patients from the general population – with the exception of those treated with antiplatelets and statins. For ACE inhibitors, treated patients with schizophrenia had a twofold higher mortality than that of treated patients from the general population, while the mortality was more than twofold higher in the case of vitamin K antagonists.
“Previous studies have found that patients with schizophrenia have increased cardiovascular mortality and a lower prescription rate for cardioprotective treatment compared with the general population,” the authors wrote.
They noted that patients with schizophrenia might have more problems with medication adherence, and pointed to another study showing this in patients with schizophrenia and diabetes. Other studies also showed that patients with schizophrenia were less likely to talk to a cardiologist after a cardiac event.
“Together, ,” they wrote. “This hypothesis could explain the results of a generally increased mortality rate among patients with schizophrenia, especially when the results suggest that these patients die of cardiovascular causes that might be treatable.”
They called for patients with schizophrenia to be followed up during treatment, and to increase treatment intensity after cardiac events, “because a diagnosis of schizophrenia may be associated with an increased cardiac risk, which potentially can be countered by secondary preventive cardiac treatment.”
In patients who received triple therapy, the mortality rates were similar for those with schizophrenia and the general population. However, there were much higher mortality rate differences between patients with schizophrenia and the general population for those receiving dual or monotherapy.
Significantly more patients from the general population were readmitted with myocardial infarction and more underwent percutaneous coronary intervention than from the group of patients with schizophrenia.
The prevalence of hypertension was similar between the two populations, but more patients with schizophrenia had diabetes and substance abuse, compared with the general population.
The authors noted that they did not have information on the severity of myocardial infarction or the effect of other lifestyle factors.
“Future research should attempt to assess the degree to which these factors contribute to the increased mortality in patients with schizophrenia,” they wrote.
One author declared grants, speaking fees and advisory roles with the pharmaceutical industry. No other conflicts of interest were declared.
SOURCE: Kugathasan P et al. JAMA Psychiatry 2018. Oct 24. doi: 10.1001/jamapsychiatry.2018.2742.