Quality of life and calcium channel blockade with nifedipine GITS versus amlodipine in hypertensive patients in Spain

Abstract

OBJECTIVE: Compliance with hypertension treatment is affected by treatment-related factors (complexity, side effects), efficacy and compound-specific effects that impact on quality of life. This study examined the differences in quality of life produced by two once-daily calcium channel blockers using different delivery systems: nifedipine gastrointestinal therapeutic system (GITS) and amlodipine. DESIGN: This was a double-blind, double-dummy, randomized clinical trial comparing nifedipine GITS (30 mg) and amlodipine (5 mg) for 24 weeks following a placebo run-in. Clinical, laboratory evaluations and quality-of-life data were assessed at screening, baseline randomization and three times during active therapy. SETTING: The study was conducted in 13 medical clinics in Spain. PATIENTS: The sample comprised 430 screened and 356 randomized patients with mild to moderate hypertension (diastolic blood pressure 95-114 mmHg). MAIN OUTCOME MEASURES: Change in systolic and diastolic blood pressure and in health-related quality of life were the main outcome measures. RESULTS: There were no significant differences between active treatment groups in the blood pressure changes (systolic blood pressure: nifedipine GITS -15.5 mmHg; amlodipine -15.7 mmHg). Spontaneous adverse events consistent with calcium channel blockage were not different. The nifedipine GITS group improved in all quality-of-life measures except Sexual Symptom Distress and showed a significantly greater improvement than amlodipine in overall Quality of Life (P< 0.05), General Perceived Health (P < 0.026) and its subscale Vitality (P < 0.019). The amlodipine group declined in overall Quality of Life, General Perceived Health, Vitality and Sleep Disturbance, and significantly in Sexual Symptom Distress (P < 0.045). However, this group improved in self-reported Cognitive Functioning (P=0.036), Mental Acuity (P < 0.005) and Detachment/disorientation (P=0.01). CONCLUSIONS: These results suggest compound-specific effects on quality of life that may be due to differences in the delivery system. Nifedipine GITS is short-acting (2 h half-life) and is delivered continuously over a 24 h period, while amlodipine has a half-life of 40 h, which may produce more sustained low-level effects. While a more beneficial profile was observed for nifedipine, amlodipine demonstrated potential positive effects on cognitive functioning.