Depression: are patient’s receiving adequate treatment?

This editorial refers to ‘Cardiovascular hazards of insufficient treatment of depression among patients with known cardiovascular disease: a propensity score adjusted analysis’, by S. Bangalore et al., on page 258. It is well known that depression is a risk factor for primary and secondary adverse cardiovascular events.1,2 The American Heart Association (AHA) recognizes depression as a major risk factor for cardiovascular disease, similar to that of diabetes, hyperlipidaemia, and hypertension.3 Further, the AHA has stated that depression can promote atherosclerotic progression and increase severity of other cardiovascular risk factors.4 Approximately 20% of patients hospitalized with an acute coronary syndrome (ACS) or myocardial infarction (MI) meet the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders criteria for major depression, with even a larger proportion having some degree of depressive symptoms.2,5,6 Depression can exacerbate physical symptoms and promote poor behaviour, such as not prescribing to recommended therapies and medication compliance, all of which can affect cardiovascular health.7–9 The economic burden of depression is substantial on both an individual and population level. Costs of depression include reduced quality of life, increase in medical costs, and loss of productivity. Depression is the leading cause of disability among adults in high-income countries10 and is associated with increased mortality because of suicide and the greater likelihood of being able to effectively manage health conditions.7 Therefore, the identification and treatment of depressive symptoms is of utmost importance. Often, depressive symptoms are undiagnosed, underestimated, or mischaracterized as cardiac symptoms. Estimates suggest that depressive symptoms are diagnosed and treated in less than 15% of cases11 and without standardized screening tools, false-negatives can be as high as 75% among MI patients.12 Current evidence indicates that approximately half of cardiologists treat depression. Reasons may be because of the belief that depressive feelings after a stressful life event (i.e. MI) are common and will subside after resumption of normal life activities. Another reason may be the uneasiness of treating the depression or that it is the responsibility of the primary care physician. However, depression is a risk factor for cardiovascular disease and therefore, these depressive symptoms could have occurred well before the event. Continuation of symptoms beyond the cardiovascular event puts patients at a higher risk for subsequent adverse events and mortality. Therefore, the use of standardized screening tools is the most effective way of determining depression and depressive symptoms. The AHA, at a minimum, recommends the Patient Health Questionnaire-2 (PHQ-2), with further evaluation if positive.13 Studies have shown that treatment of depressive symptoms among patients with cardiovascular disease result in a risk reduction for subsequent cardiovascular events and death.3,13 Because of this risk reduction, effective treatment of depression is essential. The study by Bangalore et al.14 in this issue of the journal addresses the issue of treatment adequacy for depression among patients who first received treatment for major depression disorder following a new diagnosis of MI or stroke. Depression care adequacy was assessed during the 3 months following the depression diagnosis and determined by dosage and duration adequacy. While this study is limited by identifying depression through International Classification Disease codes and not a standardized questionnaire, it certainly provides an important measure of treatment adequacy and a basis for future investigations. In this study, a total of 6763 patients were identified as having a major depressive disorder. However, only 1568 (23.2%) received antidepressant treatment. This very low proportion of patients even being treated for depression is an important finding and represents an area that can be greatly improved. While this study is limited to claims data, it is unknown whether the treating physician referred the patient to their primary care provider for treatment, the patient did not fill a prescription, or was just not treated. Regardless of the reason, there is a breakdown in the process from diagnosis to treatment. There is the possibility that patients chose to receive cognitive behaviour therapy or some other type of non-pharmacologic intervention instead of antidepressants. However, antidepressant medications are recommended to be the first treatment modality by the American Psychiatric Association and usually the first choice for treatment by clinicians.15 This study highlights the need for methods and processes that ensure that patients receive the required care for their depression. Of the 1568 patients treated for depression in the 3 months following their depression diagnosis, only 631 (40.2%) received adequate care. Those who did not receive adequate care had more baseline comorbidities and more follow-up hospitalizations. After adjustment by propensity score, inadequate antidepressant treatment was associated with an increased risk for the composite cardiovascular outcome of follow-up MI, stroke, angina, and heart failure. However, when evaluated as separate outcomes, MI and heart failure were not statistically significant. Though subsequent MI was not significantly different between those treated adequately and inadequately, the hazard ratio (1.37) is clinically relevant. This non-significance is probably attributable to the lower event rate for follow-up MI, which is most likely due to the majority of the patients within this study having a stroke (81%) compared to a MI (19%) as their baseline entry event. As with all observational studies, there are limitations to this study. Namely the use of claims data that does not allow for the assessment of the level of depressive symptoms and the large majority of patients having a stroke as their baseline entry event. Future studies, should evaluate other disease aetiologies. However, this study highlights some very important findings and areas of improvement. First, the low number of patients being treated after being identified as having a major depression disorder. Secondly, of those treated, the majority not receiving adequate treatment with antidepressants. If we are going to make progress in diminishing the impact of depression on cardiovascular disease and its influence on many of the associated deleterious behaviour and physiological effects, this study highlights those needs. The creation and institution of care process models for depression screening, diagnosis, and treating can help alleviate many of these insufficiencies. They would streamline diagnosis, ensure treatment, and provide pathways so that patients will receive adequate treatment. Conflict of interest: none declared.