Comparison between a bid and a tid regimen: improved compliance with no improved antihypertensive effect. The EOL Research Group

Abstract

Objectives: To compare compliance with an antihypertensive treatment administered either twice daily or three times daily. The two formulations of the antihypertensive treatment used (nicardipine) "regular tablets" (t.d.) and "slow release tablets" (b.d.) are bioequivalent at the daily dosage used in the study.

Study design: Open, controlled, parallel designed study with centralised, randomised allocation to the treatment groups: TID group: A nicardipine 20 mg tablet, three times daily for 3 months. BID group: A capsule of slow release (SR) nicardipine, 50 mg twice daily for 3 months.

Patients: 7274 hypertensive patients were investigated by 2.651 general practitioners. Compliance with the nicardipine was assessed by means of standardised interviews with the patients and by a questionnaire for the investigators.

Results: Compliance was slightly higher in the BID than in the TID group; 71.2% and 24.5% of patients in the first group declared their compliance was 100% and 80% compared to 82.3% and 15% in the second group. A statistically significant relationship was shown between compliance with nicardipine and the decrease in blood pressure after three months of therapy. However, no significant difference was noticed between the two groups of patients in the absolute decrease in blood pressure after the treatment period: 25.7/14.7 mm Hg in the TID group compared with 25.9/15.0 mm Hg in the BID group.

Conclusions: A difference in compliance between the bioequivalent BID and TID formulations of the same active agent was shown in hypertensive patients. However, the difference was not large enough to lead to a difference either in the number of controlled patients or in the decrease in blood pressure. Reducing the number of daily doses does not automatically lead to greater efficacy of treatment.