By Crystal Phend, Senior Staff Writer, MedPage Today
Published: April 19, 2013
Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner
ROME -- Easily distressed individuals may be at higher risk of heart disease, a Danish population-based study showed.
People who scored high for "mental vulnerability" were 37% more likely to develop fatal or nonfatal cardiovascular disease during a mean 15 years of follow-up after adjustment for top risk factors, Anders Borglykke, MSc, PhD, of the Research Center for Prevention and Health at Denmark's Glostrup University Hospital, and colleagues found.
Intermediate scores on the scale also significantly raised the risk by 23%, the group reported here at the European Association for Cardiovascular Prevention and Rehabilitation's EuroPRevent meeting.
However, mental vulnerability score added only slightly to a conventional risk stratification model suggesting "little if any role in risk stratification," the researchers concluded.
Mental vulnerability was measured on a 12-item questionnaire asking about physical and psychological symptoms such as frequent loss of appetite, sleeplessness, tiredness, as well as hands that shake easily, being easily bothered by things, feeling misunderstood, and troubling thoughts.
The measure may have been just a surrogate for some factor that has a more direct impact on the heart, Borglykke suggested in an interview.
"We think this is actually a measure for chronic stress," he told MedPage Today. "It correlates very well with stress, and stress is a risk factor for cardiovascular disease."
While the scale is unlikely to make it to the clinic, the results do add to those of prior studies suggesting a negative impact of certain personality types and depression and argue for more awareness of these nontraditional factors in cardiovascular risk assessment, Borglykke said.
His study pooled together data from three Danish population-based prospective cohort studies (Monica I and III and Inter99) for a total of 10,943 cardiovascular disease-free individuals at baseline.
About one in 10 (21%) scored as at least latently vulnerable, with three or more "yes" answers; 9% were considered vulnerable with five or more of the items reported.
The intermediate group was 17% more likely to have incident fatal or nonfatal cardiovascular disease during the mean 15.2 years of follow-up (hazard ratio 1.17, 95% confidence interval 1.06 to 1.29).
That risk was elevated 29% with a higher mental vulnerability score (95% CI 1.14 to 1.45).
These associations remained significant and actually strengthened to hazard ratios of 1.37 and 1.23, respectively, after controlling for the classic risk factors of age, sex, smoking, systolic blood pressure, and total cholesterol.
Adding mental vulnerability as a factor atop the conventional factors did significantly increase the C-index as a measure of predictive ability but the effect was small and there were small significantly negative effects for the integrated discrimination improvement and net reclassification improvement as well (differences of 0.004, -0.028, and -0.088, respectively).
The scale could still have some clinical utility in patient subgroups, Borglykke told attendees gathered at his poster discussion.
"Perhaps it could play a role if we break our population down in groups, like women or the younger age groups and so on," he said.
Men in the cohorts tended to have lower scores on the scale than women, albeit not a significant difference (P=0.09 for interaction). Higher scores were associated with higher rates of smoking, from 45% among individuals with a score of 2 or less to 49% at 3 to 4 and 57% at 5 or higher.
However, the study left out one of the "famous three confounders -- age, sex, and socioeconomic status," cautioned Simon Capewell, MD, DSc, a public health and policy professor at the University of Liverpool, England, noting the absence of socioeconomic data. Capewell lead the poster discussion.
Other factors not controlled for were stress biomarkers, diet, and alcohol intake, Borglykke acknowledged.
The researchers reported having no conflicts of interest to disclose.
Primary source: EuroPRevent Source reference: Borglykke A, et al "Mental vulnerability as a predictor of cardiovascular disease and death" EuroPRevent 2013; Abstract P52.