Type B aortic dissection (TBAD) patients exhibit poor adherence to best medical therapy, which may play a part in the high levels of aortic morbidity and mortality seen in this patient cohort, according to research presented by Colin Bicknell (London, UK) at the 2017 Critical Issues meeting (19–20 May, Nuremberg, Germany).
“Best medical group patients do not fare well,” Bicknell told the audience, with relatively high probabilities of dissection progression and death, and poor survival out to six years.
The rate of medication adherence is unknown in TBAD patients. However, Bicknell noted, for the general hypertensive population, only 37% of patients have adequately-controlled blood pressure. Half of all hypertensive patients are non-adherent in their first year of treatment, even though it is known that higher levels of adherence results in better blood pressure controlled and reduced cardiovascular morbidity.
Bicknell and colleagues conducted a cross-sectional mixed methods study in their tertiary centre for complex aortic disease. The study considered demographics, patient disease specific knowledge, and psychological and behavioural predictors of adherence—a “Health Belief Model”. Bicknell and colleagues specifically examined self-reported adherence using validated measures.
In the 47 patients analysed, Bicknell and colleagues found a “high adherence” rate of 42.5%, a “medium adherence” rate of 36.2% and a “low adherence” rate of 21.3%.
The results indicated that “psychological behaviours have a strong bearing on adherence,” Bicknell explained. Some of the most notable demographic, psychological and behavioural predictors of adherence were:
- Previous aortic surgery (ß 0.332, p=0.03)
- Greater number of medications (ß 0.332, p=0.026)
- Fewer medication side effects (ß=0.272, p=<0.014)
- Better memory (ß=0.579, p=<0.001)
- Higher perceived benefit (ß= 0.486, p=<0.001).
Bicknell also noted that, overall, patients had poor knowledge of TBAD as a condition, posting a mean test score of 8.8/16.
“Medication adherence is poor in TBAD patients which may play a part in the high levels of aortic morbidity and mortality in this cohort and there are specific strategies that may help,” concluded Bicknell. “Can we robustly compare strategies when half of one treatment group does not receive the intervention?”