Drug adherence and psychological factors in patients with apparently treatment-resistant hypertension: Yes but which ones?

The aim of the study was to assess drug adherence, as well as association of psychological factors with both drug adherence and severity of hypertension in two subtypes of patients with apparently treatment-resistant hypertension (ATRH): younger patients with uncomplicated hypertension (YURHTN) versus patients ≥60-year-old and/or with a history of cardio- or cerebrovascular complication (OCRHTN). Drug adherence was assessed in urine by targeted Liquid Chromatography-Mass Spectrometry. The severity of hypertension was assessed by 24-h ambulatory blood pressure adjusted for the number of antihypertensive drugs and for drug adherence. Psychological profile was assessed using five validated questionnaires. The proportion of totally non-adherent patients was three times higher (24.1 vs. 7.1%, P = 0.026) in the YURHTN (n = 54) than in OCRHTN subgroup (n = 43). Independent predictors of drug adherence in YURHTN were ability to use adaptive strategies, male sex and family history of hypertension, accounting for 39% of variability in drug adherence. In the same subgroup, independent predictors of severity of hypertension were somatization and lower recourse to planification, accounting for 40% of variability in the severity of hypertension. In contrast, in the OCRHTN subgroup, independent predictors of drug adherence and severity of hypertension were limited to the number of yearly admissions to the emergency room and the total number of prescribed drugs. In conclusion, poor drug adherence and altered psychological profiles appear to play a major role in younger patients with ATRH devoid of cardiovascular complication. This subgroup should be prioritized for chemical detection of drug adherence and psychological evaluation.