Coronary artery disease (CAD) remains one of the leading causes of morbidity and
mortality worldwide, with multiple risk factors influencing its onset and progression.
Among the psychosocial factors associated with CAD, depression plays a particularly
prominent role. Research indicates that while 17% to 27% of patients with CAD have major
depression, a significantly larger percentage experience subsyndromal depressive
symptoms. This highlights a widespread issue where depressive symptoms, even if not
clinically classified as major depression, still contribute to poorer health outcomes in
CAD patients. Major depression is not only prevalent among CAD patients but is also
linked to an increased risk for developing CAD and higher mortality from the disease.
However, the exact mechanisms through which depression impacts cardiovascular health
remain unclear.
Coronary heart disease (CHD), a major manifestation of CAD, typically results from the
rupture or erosion of an atherosclerotic plaque in the epicardial coronary arteries. Over
60 risk factors and markers have been associated with the initiation and progression of
these plaques. When a plaque ruptures, it can stimulate acute thrombosis within the
artery, leading to an acute coronary syndrome (ACS), which may present as a myocardial
infarction (MI), unstable angina, or even sudden cardiac death. These risk factors can be
broadly categorized into three groups: lifestyle, biological, and psychosocial.
Depression, as a psychosocial risk factor, not only increases the likelihood of
developing CAD but also contributes to worse outcomes in patients who already have the
disease.
The impact of depression extends beyond its role in the progression of CAD; it
significantly affects the quality of life (QOL) of patients with coronary disease. While
treating depression may not necessarily reduce depression's role as a direct risk factor
for CAD, improving the quality of life should be considered a primary goal of treatment.
Defining and measuring QOL remains a challenge, but recent studies have shown a clear
relationship between QOL, depression, and mortality risk in CAD patients. This
underscores the importance of addressing both the psychological and physical health of
CAD patients in clinical care.
Moreover, the PHQ-9 (Patient Health Questionnaire-9) is a widely used, self-administered
tool designed to assess the severity of depression in individuals. Comprising nine
simple, straightforward questions, the PHQ-9 evaluates the frequency of common depressive
symptoms over the past two weeks, such as feelings of sadness, loss of interest, sleep
disturbances, and fatigue. Each response is scored on a scale from 0 to 3, and the total
score helps determine the severity of depression, ranging from minimal to severe.
Originally developed as a screening tool, the PHQ-9 is now a key instrument in both
clinical practice and research for diagnosing major depressive disorder (MDD), monitoring
treatment progress, and identifying individuals at risk for worsening symptoms. A
meta-analysis conducted in 2015, which included 36 studies with over 21,000 participants,
evaluated the sensitivity and specificity of various cut-off scores ranging from 7 to 15.
The analysis found that the standard cut-off of 10 had a pooled sensitivity of 0.78 and
specificity of 0.87, suggesting it is a reasonably effective screening tool. However, the
study also noted significant limitations, such as incomplete reporting on cut-off scores
other than 10, which led to misleading results indicating that sensitivity increased with
higher cut-off scores, possibly due to selective reporting in some studies.
Despite the well-established connection between depression and CAD in many parts of the
world, there is a notable gap in research on this topic within Iraq. This study aims to
assess the prevalence and severity of depression among CAD patients in Baghdad using the
Patient Health Questionnaire-9 (PHQ-9), a widely recognized tool for diagnosing
depression. By exploring the burden of depression in this patient population, this
research will provide important insights into the mental health needs of CAD patients in
Iraq and contribute to improving both cardiovascular outcomes and quality of life in this
underserved region.
