Which Comes First, Panic Disorder or CAD?

The connection between panic disorder (PD) and coronary artery disease (CAD) has been noted for decades, but exactly how they are connected is not known. People with PD often report symptoms that overlap those of CAD, according to researchers from the University of Adelaide, University of Freiburg, and University of Ulm. Or is it a case of misdiagnosis, in which people with PD are having somatic symptoms of undiagnosed coronary conditions?

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The complicated interlinking along with the fact that PD patients have been shown to have high levels of coronary health care indicates that a meta-analysis is “both timely and warranted,” according to the researchers. They reviewed 12 published studies involving 1,131,612 patients and 58,111 cardiac events (major adverse cardiac events [MACE], structural CAD, ischemic heart disease, or other diagnosed cardiovascular disease). Incident myocardial infarction (MI) was the most common individual endpoint. In 6 studies, 18,541 MI events were reported in 953,888 patients.

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Panic disorder was associated with incident CAD even after excluding angina. The researchers found that high-quality evidence suggested that PD was an independent risk factor for incident MI; moderate evidence supported an association between PD and MACE. Only low-quality evidence indicated a link between PD and CAD, and no association was seen between PD and fatal CAD. However, the researchers note that the findings are “tempered” by heterogeneity between study estimates and risk of biases.

The risk for CAD was significantly high after excluding depression. The researchers do note that some of their review suggests that both depression and generalized anxiety could be associated with incident CAD. Adjusting for depression and antidepressant medication attenuated CAD risk attributable to PD by 24% in studies that included depression as a factor. Previous studies have reported CAD risks in the range of 30% to 90% for patients with depression. “Indeed, recent decades have focused almost exclusively on depression disorders,” they say, “which remain the primary psychiatric intervention in established CHD populations,” although posttraumatic stress disorder and anxiety disorders are taking on more importance.

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Cognitive behavioral therapy, serotonergic reuptake inhibitors, benzodiazepines, and combinations of those may have a benefit in lowering the incidence of CAD, but the effects are unclear. The researchers note that the IMPACT trial showed that collaborative depression care reduced MACE by 48% at 7-year follow-up in patients without established CAD.

Other researchers have proposed that platelet abnormalities, inflammation, changes in the QRS complex, and other mechanisms might underlie the association between PD and CAD. Recent studies have linked PD and atrial fibrillation and suggest that PD and panic attacks could lead to higher sympathetic discharge and myocardial ischemia.

However, until studies are done that remove the heterogeneity sources (eg, age, sex, length of follow-up, and diabetes mellitus) in the meta-analysis studies, the relationship between PD and CAD remains a chicken-egg conundrum.

Source: Tully PJ, Turnbull DA, Beltrame J, et al. Psychol Med. 2015;45(14):2909-2020.
doi: 10.1017/S0033291715000963.