Adherence to Antihypertensive Medications in Type 2 Diabetes: Prevalence and Determinants
Y. P. M. Van Camp *
Faculty of Medicine and Health Sciences, Universiteit Antwerpen, Centre for Research and Innovation in Care (CRIC), Wilrijk, Belgium.
B. Vrijens
Department of Biostatistics and Medical Informatics, University of Liège, Liège, Belgium and MWV, Visé, Belgium.
I. Abraham
University of Arizona, Center for Health Outcomes and Pharmacoeconomic Research (HOPE), Tucson, Arizona, USA.
B. Van Rompaey
Faculty of Medicine and Health Sciences, Universiteit Antwerpen, Centre for Research and Innovation in Care (CRIC), Wilrijk, Belgium and Department of Healthcare, Artesis University College of Antwerp, Antwerp, Belgium.
M. M. Elseviers
Faculty of Medicine and Health Sciences, Universiteit Antwerpen, Centre for Research and Innovation in Care (CRIC), Wilrijk, Belgium.
*Author to whom correspondence should be addressed.
Abstract
Aim: To estimate the extent of non-adherence to antihypertensive drugs in type 2 diabetes.
Study Design: Observational.
Place and Duration of Study: The study was conducted at three Belgian specialised diabetes centres during two months.
Methodology: Included were adult type 2 diabetes patients, treated with insulin and either ACE-inhibitors or sartans. Adherence was assessed electronically with the Medication Event Monitoring System. A standardised blood pressure measurement was taken at the study start and end.
Results: Mean age of the 130 included patients was 65 and 51% was male. Mean HbA1c was 7.5mg% (59mmol/mol), mean BMI 32kg/m2 and mean daily oral pill burden 8. Half of the patients showed perfect adherence and another fourth missed the prescribed dose on only 1 of 56 days. Mean baseline blood pressure was 143/77mmHg and 25% had controlled blood pressure (<130/<80mmHg). Higher hypertension knowledge was associated with adherence and higher daily doses of insulin with non-adherence. Adherence correlated positively to diastolic, but not systolic blood pressure. Of patients never missing a dose 78% reached controlled diastolic blood pressure compared to 68% of patients missing doses on ≥3 days.
Conclusion: Adherence to antihypertensive medications was high in this cohort followed up at specialised diabetes centres. Still, about 15-20% had suboptimal adherence and should receive adherence enhancing support, especially since high adherence seems necessary to obtain blood pressure control.
Keywords: Diabetes, hypertension, medication, adherence.