Elsevier

Clinical Therapeutics

Volume 33, Issue 1, January 2011, Pages 121-134
Clinical Therapeutics

Pharmaceutical economics & health policy
Original research
Medication Adherence Affects Treatment Modifications in Patients With Type 2 Diabetes

https://doi.org/10.1016/j.clinthera.2011.01.024Get rights and content
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open access

Abstract

Background

Low rates of treatment modification in patients with insufficiently controlled risk factors are common in type 2 diabetes. Although adherence problems are often mentioned in surveys as a reason for not intensifying treatment, observational studies have shown inconclusive results.

Objective

To assess how medication adherence affects treatment modifications for hypertension and hyperglycemia in patients with type 2 diabetes.

Methods

This was a cohort study of 11,268 primary care patients with type 2 diabetes in the Netherlands. Inclusion criteria were diagnosis before 2007, ≥1 prescription to antihypertensive or glucose-regulating medication in the preceding 6 months, and a systolic blood pressure level ≥140 mm Hg or glycosylated hemoglobin ≥7% in 2007. Patients on maximal treatment were excluded. Treatment modifications as observed from prescriptions were classified as none, dose increase, dose decrease, class switch, class addition, or class discontinuation. Refill adherence was assessed as medication possession ratio or length of last gap between refills. We performed multilevel multinomial regression analysis to test for associations.

Results

We included 4980 diabetic patients with elevated blood pressure and 2945 diabetic patients with elevated glycosylated hemoglobin levels. Patients with lower adherence for antihypertensive drugs were more likely to have those medications discontinued (odds ratio [OR] for every 10% lower medication possession ratio =1.22; 95% CI, 1.11–1.33) or the dose decreased (OR = 1.14; CI 1.01–1.28). For glucose-regulating medication, dose increases (OR = 0.92; 95% CI, 0.85–0.98) and medication additions (OR = 0.90; 95% CI, 0.82–0.99) were less likely in patients with lower adherence levels.

Conclusions

Low adherence inhibits the intensification of glucose-regulating but not antihypertensive medication in type 2 diabetic patients with insufficiently controlled risk factors in the Netherlands. Adherence problems may lead to diminished or even discontinued antihypertensive treatment.

Key words

hyperglycemia
hypertension
medication adherence
primary care
therapy modification
type 2 diabetes

Cited by (0)

Members of GIANNT are listed in the Acknowledgments.