Objective : To examine the association between the combination therapy of calcium antagonists with angiotensin converting enzyme (ACE) inhibitors and underlying diseases for hypertensive patients.
Design : Cross-sectional survey of the drug utilization.
Methods : This survey included 603 hypertensive patients who had visited Toyama Medical and Pharmaceutical University Hospital, Toyama, Japan more than twice from January to June in 1996 and received the prescriptions of calcium antagonists and/or ACE inhibitors. Main outcome measure was the combined medication of calcium antagonists with ACE inhibitors. Underlying diseases under consideration were diabetes mellitus (DM), hyperlipidemia (LIPID), ischemic heart disease (IHD), chronic heart failure (CHF), and ischemic stroke (STROKE).
Results : Out of 603 hypertensive patients, 57.5% received only calcium antagonists, 23.7% received only ACE inhibitors, and 18.7% received both of them. Patients with either IHD or CHF tended to receive the combination therapy as compared to DM or LIPID. Although men tended to receive the combination therapy, a gender effect might be a confounder for the association. Logistic regression showed a 33% increase (P=0.265) in frequency of the combination therapy in patients with IHD after adjusting for age and gender.
Conclusion : Some underlying diseases were associated with more frequent prescriptions of the combination therapy for hypertensive patients, especially with ischemic heart diseases. This result should be regarded as an exploratory stage although the pattern of antihypertensive drug use could be reasonably explained from the pharmacological sense.