In the present study we found that depressive, hypertensive participants at high cardiovascular risk had better BP values.
Although depression is considered an independent risk factor for hypertension incidence, and a number of authors have found it related to higher BP levels [19–21], its role in the control of BP values remains unclear . Limited data have reported that hypertensive patients taking antidepressants have lower blood pressure levels . One possible explanation for the effect of antidepressants on lowering blood pressure could be a reduction in vagal activity, decreased heart rate variability and baroreflex sensitivity , and neuro-endocrine pathways [25–29]. Our results concur with other studies performed in general populations [12, 13, 24, 30]. Research analyzing a group of people with hypertension who were taking antihypertensive drugs has also shown that individuals with episodes, or symptoms of depression, tended to have lower SBP and DBP . It is not clear whether depression is the cause or the consequence of differences in the control of BP values [32, 33]. Confounders related to both hypertension and depression, such as physical activity, low-fat diet, non-smoking, and alcohol intake, were included in our analysis . Some antidepressant, anti-anxiety, and antipsychotic agents, either alone or in combination with cardiovascular therapies including antihypertensive drugs, have been reported to induce a drop in BP [35–37]. Our participants diagnosed with depression, and those taking antidepressant treatments, received more antihypertensive drugs. Nevertheless, the association observed between depression and better blood pressure values persisted after adjusting for this variable in the multivariate analysis, which indicates that this association may be independent, as has been shown in previous studies [24, 33].
It could be hypothesized, moreover, that the frequent use of health services by depressive patients could contribute to an accurate follow-up and good control of their hypertension. The Spanish Health System guarantees a free and universal access to primary healthcare services. In addition, family doctors have access to well-established chronic care protocols, which ensure the better control and follow-up of patients with co-morbidity (hypertension and depression).
Implication of our results
Our findings indicate the relevance of performing a holistic approach to the co-morbidity when tackling the care of chronic patients attended in primary care. Preventions among family physicians toward the use of antidepressants in hypertensive patients with depression should be addressed individually since many studies have shown an improvement in BP control.
Study limitations and strengths
The cross-sectional design of our study does not allow causal inferences to be drawn. Future observational research studies are needed to establish the role of psychosocial factors in the good control of cardiovascular risk factors and the prognosis of cardiovascular diseases, especially in hypertensive individuals or those at high cardiovascular risk.
For reasons of statistical power the different antidepressants were grouped together. It is possible that a larger sample could establish variations according to the antidepressant analyzed. The time elapsed from the first diagnosis of depression could not be used as a proxy for the current prevalence of depression as the only way to establish the current state of the disease is through the prescription of antidepressants, and no specific tests were conducted in the participants. We had information about the family history of cardiovascular diseases history but none concerning about family history of depression and hypertension.