People diagnosed with bipolar disorder, schizophrenia or schizoaffective disorder may be more susceptible to high-risk heart disorders at a younger age, according to a new study published in the American Heart Association Journal.
The study, first published on March 9, was led by Dr. Rebecca C. Rossom, a senior research investigator in behavioral health at the Center for Chronic Care Innovation at HealthPartners Institute in Minneapolis, Minnesota. The research team examined the estimated 10- and 30-year cardiovascular (CVD) risk in primary-care patients with and without serious mental illness (SMI).
Close to 600,000 adults in the US between the ages of 18-75 were included in the initial stage of the study, which took place in Minnesota and Wisconsin from January 2016 to September 2018. Analyzing the subjects during primary-care visits, the researchers placed them into groups depending on whether they had been diagnosed with SMI or not.
Then, the 10-year CVD risk in people without any preexisting heart conditions was calculated using a combination of the atherosclerotic cardiovascular disease scores (ASCVD), and the 30-year risk was calculated using Framingham risk scores.
The ASCVD risk score is a national guideline developed by the American College of Cardiology and is used to calculate the 10-year risk of a patient having a cardiovascular problem, such as a heart attack or a stroke. The Framingham risk score is similar, although it uses a gender-specific algorithm to determine cardiovascular risk in patients.
Once the risk data was collected, the researchers moved on to collecting more information from the patients’ health records, including the individual’s demographic, vital signs, medication, diagnosis and health-insurance data.
Discrepancies between independent and dependent variables were then examined through descriptive statistics, a summary statistic that summarizes features from a collection of information. This included demographic characteristics such as age, sex, race, ethnicity and health-insurance coverage. Because of the way in which these characteristics drastically differed from patient to patient, the study models were adjusted to take them into account.
Out of 591,257 patients who were assessed, 11,333 (1.9%) were considered to have a serious mental illness, while the remaining 579,924 did not.
Of those diagnosed with SMI, the majority had bipolar disorder (70.6%), followed by schizoaffective disorder (17.6%) and schizophrenia (11.7%), the researchers found. On average, patients with SMI tended to be younger and were more likely to be female, they said. There was also a higher likelihood of SMI in Black or Indigenous American patients.
While the researchers found that the 10-year CVD risk was not significantly different in patients with SMI and those without, the 30-year risk was significantly higher for patients with SMI.
Patients with SMI had a 10-year CVD risk of 9.5%, compared with 8% risk for those without SMI.
Regarding 30-year risk, 25% of patients with SMI were in the highest-risk tier for heart disease, compared with 11% of patients without SMI.
What contributes to the higher risk of heart disease?
In similar studies conducted in the past, the elevated CVD risk was largely attributed to decreased or delayed medical treatment for patients with SMI. In the new study, the researchers found there may be many other contributing factors. These factors include increased alcohol use, lower physical activity, poorer socioeconomic status and a lower-quality diet. Additionally, many of the medications used to treat various mental illnesses have side effects that increase the risk of heart conditions.
Two particular factors were especially noted by the study’s authors: higher smoking rates and higher rates of obesity in young adults with SMI.
Up to 50% of SMI patients met the criteria for obesity, compared with 36% of non-SMI patients. Similarly, 36% of patients with SMI were current smokers, compared with 12% of patients without SMI.
Among the three specified mental disorders examined in the study, patients with bipolar disorder had the highest 10-year CVD risk; those with schizoaffective disorder had the highest 30-year CVD risk.
Furthermore, due to including patients with other mental-health conditions in the “patients without SMI” group, the estimates of elevated CVD risk for “patients with SMI” may even be conservative, the study found.
“Given evidence that people with SMI die significantly earlier than their peers, increased time spent in better midlife cardiovascular health has significant benefits for cardiovascular outcomes later in life,” Rossom wrote, adding that interventions to address and treat CVD risk in patients with SMI would be more impactful if initiated earlier rather than later.
“We encourage healthcare systems and clinicians to use the 30-year cardiovascular-risk estimates for young adults with serious mental illness, as these may be used starting at age 18,” she said. “Right now, estimates of 10-year heart-disease risk are used most frequently, and they cannot be applied until people are at least 40 years old, which is too late to start addressing heart-disease risk in people with serious mental illness.”