Study: Cognitive symptoms of depression cannot be discarded as risk factors for heart disease progression

Nov 11 2010

Cognitive symptoms of depression cannot be simply discarded as risk factors for heart disease progression. When using a structured diagnostic interview, both somatic and cognitive symptoms of depression are associated with adverse cardiac outcome after adjusting for potential confounders.

Evidence indicates that self-reported somatic/affective but not cognitive/affective symptoms of depression are highly prevalent in cardiac patients, and are predictive of cardiovascular mortality and cardiac events, even after somatic health status has been controlled for. These findings may help to develop symptom-targeted interventions to reduce both depression and cardiac disease progression. However, one major disadvantage of the analyses conducted so far is that they relied on self-report instruments, such as the Beck Depression Inventory. A drawback of self-reported depressive symptoms is that no weighing of symptoms is performed, as is carried out when establishing a psychiatric diagnosis with a structured interview. In the latter, symptoms only count when they are present most of the time, for at least 2 weeks, affect daily functioning and are not a consequence of a physical condition. As a result, it remains unclear to what extent findings using self-reported symptoms reflect clinically meaningful information.

The Authors of this study therefore evaluated the independent association between cardiovascular prognosis and ratings of the individual depressive symptoms based on a structured diagnostic interview. They used data from the Depression after Myocardial Infarction study (DepreMI), a naturalistic follow-up study which took place in 4 hospitals in the northern part of the Netherlands. The study included 468 MI patients, of whom 118 met DSM-IV criteria for post-MI depressive disorder, and 115 had a cardiac event during a mean follow-up of 2.5 ± 0.8 years. They used an adapted version of the Composite International Diagnostic Interview (CIDI) version 1.1, a fully standardized psychiatric diagnostic interview that can be used to assess mental disorders according to the definitions and criteria of DSM-IV. Thus, using symptom-specific data from a structured diagnostic interview, the following findings were obtained. First, they confirmed that, after adjusting for potential confounders, the presence of somatic symptoms of depression was associated with an increased risk of cardiovascular events. Second, in contrast with previous studies using self-report data, interview ratings of cognitive symptoms of depression were also associated with a significantly increased risk in multivariate analysis, although less strongly than somatic symptoms (HR = 1.20 and 1.39, respectively). Third, contrary to previous studies, adjustment for potential confounders resulted in higher effect estimates, while generally in studies using self-report data adjustment leads to lower estimates. These discrepancies may be explained by the fact that interview-based symptoms are based on strict criteria derived from the DSM, based on their presence, severity, consequences and etiology. This may result in less attenuation of the estimates by potential confounders compared to self-report data. The use of interview-based measurement may be more sensitive in detecting clinically relevant cognitive symptoms, and it is possible that these clinically relevant cognitive symptoms result in a higher level of cardiotoxicity.

In conclusion, when using a structured diagnostic interview, both somatic and cognitive symptoms of depression were associated with adverse cardiac outcome after adjusting for potential confounders. Cognitive symptoms of depression cannot be simply discarded as risk factors for heart disease progression. Rather, for a better understanding of the association between depression and cardiovascular disease progression, a more thorough assessment of depressive symptoms is needed by using interview-based ratings in addition to self-report data.

SOURCE alphagalileo.org