Symptoms of depression and anxiety and adherence to antihypertensive medication

In spite of considerable advances in the treatment of hypertension, only 69% of known hypertensive patients receiving pharmacologic treatment in the United States have their blood pressure controlled.1 Hypertension control rates in other developed countries are even lower, ranging from 20 to 50%.2 Failure to control hypertension is largely due to nonadherence to prescribed treatments. In fact, adherence during the first year of treatment is about 50%3,4 and 50% of patients with refractory hypertension are in fact nonadherent.5 Nonadherence lessens the efficacy of antihypertensive drugs in preventing stroke, coronary heart disease, and chronic kidney disease.6 Moreover, increasing antihypertensive drug use by 20% would result in a fourfold return on investment, mostly attributable to a reduction in hospitalization rates.7 Although multiple risk factors have been proposed, only regimen complexity,8,9 and drug-related side effects9 have been shown to be clearly associated with prospective adherence. Owing to its high incidence and large health impact, it is imperative to identify factors associated to nonadherence, particularly those that are amenable to change. Depression and anxiety could impair cognitive focus, energy, and motivation and might affect the desire and ability of the patient to follow treatment recommendations.10 Indeed, cross-sectional studies have shown higher nonadherence in hypertensive patients with increased severity of depression symptoms,11,12 but these studies are particularly prone to selection, information, and reverse causality bias.13 The aim of our study was to assess the impact of symptoms of depression and anxiety on adherence to antihypertensive medication in a cohort of newly treated hypertensive patients.