Depression is linked to the development and progression of CHF and other cardiovascular diseases (CVD) [13-16]. However, anxiety and stress have not been as clearly associated with poor clinical outcomes in CHF patients . Despite the adverse impact of depression, anxiety, and stress on CHF patients, these disorders remain underdiagnosed and undertreated in this high-risk population[17, 18]. This problem is significant in patients residing in LMIC, who generally have less sophisticated health care systems, which are often unable to optimally screen, diagnose and manage CHF patients with these comorbidities.
In our study, 52.4% of patients had symptoms of depression. This is significantly high compared to most studies in high-income countries. In a community-based study conducted in the United States of America, the prevalence of depression in CHF patients was 17% . Furthermore, Haworth et al. studied 100 outpatients with heart failure in the United Kingdom and found the prevalence rate for anxiety and depression to be 18% and 29%, respectively . The higher prevalence of symptoms of depression in our patients is likely influenced by socioeconomic factors unique to populations in LMIC. This is supported by two studies conducted in Ethiopia and Pakistan, where the prevalence of depression was reported in 51.1 % and 60%, respectively [19, 21].
Depression and anxiety are common yet underreported in CHF and should not be overlooked when managing these patients. This is particularly important since both conditions have been associated with poor outcomes with more robust evidence for depression . In a systematic review evaluating the prevalence, variance, and measurement tools for anxiety in patients with heart failure, the pooled prevalence from 38 studies ranged from 6.3 to 72.3% . In our study, anxiety and depression coexisted in 72.7% of patients. Such a finding emphasizes the need to screen for both conditions since the treatment plan differs between the two conditions.
The use of screening tools, such as the 2 and 9-item Patient Health Questionnaires , improves the recognition of these psychiatric disorders in CHF patients, and this strategy is currently endorsed by the American and European heart failure societies [23, 24]. However, to accurately diagnose depression, anxiety and stress in CHF patients may be challenging due to the overlap of somatic symptoms shared between CHF and these psychiatric disorders. Hence, the use of formal diagnostic criteria such as the Diagnostic and Statistical Manual of Mental Disorders (DSM) and a focused clinical interview are still considered best practice during patients' evaluation process [17, 18]. Furthermore, screening for psychiatric disorders in the acute admission or early post-discharge phase may help identify CHF patients with positive symptoms. However, these symptoms may regress in the sub-acute and long-term period and may not represent a true psychiatric disorder . It may also be a normal response for newly diagnosed CHF patients to present with these somatic symptoms.
Potential mechanisms linking depression and anxiety with poor heart failure outcomes include inflammation, autonomic dysfunction, enhanced platelet aggregation, endothelial dysfunction, poor diet, smoking, and reduced physical activity . There is a paucity of data on the prevalence of stress in CHF patients. However, there is a well-established relationship between prolonged emotional or physical stress and activation of the autonomic nervous system, increasing the likelihood of myocardial infarction, arrhythmias, heart failure and sudden cardiac death [26, 27].
In a study by Gottlieb et al., involving 155 patients with heart failure, 48% of the participants met the diagnostic criteria for depression, based on the Beck Depression Inventory, and had a mean MLHFQ score of 54 (SD=± 24) . In our study, patients with symptoms of depression also had a higher median MLHFQ score of 28 (IQR: 10-54) (p=0.000). However, in the multivariate logistic regression model, a higher MLHFQ score was not statistically significant as an independent predictor of depression (p = 0.054).
The six-minute walk test is a simple, reproducible test sensitive to changes in functional capacity . Furthermore, a self-perceived feeling of depression is a determinant of a shorter six-minute walk test . In our study, a longer distance walked during the six-minute walk test was associated with a reduced likelihood of symptoms of depression.
Permanent employment offers financial security and a sense of purpose in life, hence improving the health-related QoL. In our study, only 29.2% of patients with permanent employment had symptoms of depression. Moreover, in the multivariate logistic regression model, permanent employment reduced the likelihood of having symptoms of depression. Similar findings were reported in a study involving 231 hospitalised patients with CHF in Greece, where unemployment was associated with a poor quality of life, anxiety and depression .
Other published predictors of depression in heart failure include advanced age, the female gender, a low socioeconomic status, a previous depressive episode, smoking, a higher NYHA functional class and unmarried status [20, 21, 32-34]. In our cohort, the NYHA functional class was not an independent predictor of depression. Thirty-nine percent of patients in NYHA functional class I had symptoms of depression, compared to only 18.5% in NYHA functional class III, suggesting that other confounding factors, such as the socioeconomic status, could play an important role in acquiring symptoms of depression.
This study highlights the high prevalence of depression, anxiety and stress in CHF outpatients from a middle-income country. In our cohort, the presence of orthopnea and a short six-minute walk test distance were independent predictors of depressive symptoms. Furthermore, efforts to keep CHF patients economically active also need to be explored as permanent employment reduced the likelihood of having symptoms of depression. The high prevalence of depression, anxiety and stress in CHF patients warrants routine clinical screening during follow-up visits and the collaborative management of these patients by psychologists, psychiatrists, and cardiologists.
This study was limited by a small sample size and patient enrolment from a single medical centre. Patients were recruited over a short period, and only included study participants who could communicate in English. In our study, the DASS-21 questionnaire was the only tool used to assess symptoms of depression, stress and anxiety and patients were not subsequently interviewed by a psychologist or psychiatrist. We are mindful that the prevalence of the symptoms of depression is significantly influenced by the measurement tool used. There is no data suggesting that the DASS-21 questionnaire under or overestimates the prevalence of depression, stress, and anxiety. Lastly, this study was a cross-sectional analysis with no patient follow-up data to assess for progression of symptoms of depression, anxiety, or stress. Despite these limitations, our study demonstrates that depression, anxiety and stress symptoms are common in CHF patients residing in a middle-income country.