Does comorbidity explain trends in prescribing of newer antihypertensive agents?

Concerns exist about heavily prescribing of new drugs when the evidence on hard outcomes is still limited. This has been the case for the newer classes of antihypertensives, especially in hypertensive patients without additional comorbidity. The association between comorbidity and trends in prescribing of angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARBs) was examined for the period 1996-2000.

Data were obtained from the Integrated Primary Care Information database, which contains medical records from more than 100 general practitioners in the Netherlands. Prevalent drug use in hypertensive patients was determined per calendar year. As initial treatment, the first antihypertensive drug prescribed within 1 year after diagnosis of hypertension was considered. Logistic regression was used to estimate the likelihood of receiving either ACE-I or ARBs.

The overall prevalent ACE-I use remained stable (31%), but it increased from 33 to 41% in hypertensive patients with diabetes, heart failure, proteinuria and/or renal insufficiency. ARB use increased significantly from 2 to 12%; this trend did not differ between patients with or without specific comorbidities. Initial ACE-I use slightly decreased (from 29% to 24%), whereas initial ARB use significantly increased (from 4% to 12%). ACE-I were more likely to be the first treatment in patients with diabetes [odds ratio (OR)=3.9; 95% confidence interval (CI) 3.2-4.9] or hypercholesterolemia (OR=1.4; 95% CI 1.1-1.8). ARBs were more likely to be the initial treatment in patients with asthma/chronic obstructive pulmonary disease (OR=1.6; 1.2-2.3), diabetes (OR=2.1; 1.5-2.9) or hypercholesterolemia (OR=1.7; 1.2-2.4).

The increased use of ACE-I is mostly restricted to hypertensive patients with comorbidities for which their use has been recommended. Trends in prescribing of ARBs are not related to relevant comorbidities.