Efficacy, tolerability and influence on "quality of life" of nifedipine GITS versus amlodipine in elderly patients with mild-moderate hypertension.

OBJECTIVE

The main purpose of this study was to compare efficacy, tolerability and influence on quality of life (QOL) of nifedipine gastrointestinal therapeutic system (NI) 30-60 mg once a day vs amlodipine (AM) 5-10 mg once a day in elderly patients with mild-moderate hypertension.

DESIGN

This was a randomized, double-blind, parallel-group, multicenter study. After a 2-week single-blind placebo run-in, patients were randomized to either NI 30 mg or AM 5 mg. Responders continued on the same dosage for 16 additional weeks, while non-responders were titrated to 60 mg NI or 10 mg AM.

METHODS

Blood pressure was measured by mercury sphygmomanometer and efficacy equivalence of NI and AM tested by covariance analysis. Diastolic blood pressure (DBP) was the primary efficacy parameter, its baseline value being taken as covariate while centers effect and treatment interaction were included as fixed effects in the analysis model. The secondary efficacy variables systolic blood pressure (SBP) and scores for QOL were analyzed according to the same model.

RESULTS

At the end of the study, overall mean DBPs, calculated as least-square means (LSMEANS), in the "by protocol" population were 87.5 mmHg for NI and 86.7 for AM (difference 0.8 mmHg with 90% CI -1.2 to 2.8 mmHg). In the "by intention to treat" (ITT) population LSMEANS were 87.6 mmHg for NI and 86.4 mmHg for AM (difference 1.2 mmHg with 90% CI -0.6 to 3.1 mmHg). SBP LSMEANS in the "by protocol" population were 147.7 mmHg for NI and 147.3 mmHg for AM (difference 0.3 mmHg, with 90% CI -3.7 to 4.3); corresponding values in the "by ITT" population were 148.0 mmHg for NI and 147.2 for AM (difference 0.8 mmHg, with 90% CI -2.8 to 4.6). Mean values for QOL parameters were not significantly different. A total of 173 episodes of adverse events were documented in 54 patients (26 NI and 28 AM), dropouts were 15 (20% of group) on NI and 21 (28%) on AM.

CONCLUSIONS

NI 30-60 mg was shown to be as efficacious and safe as AM 5-10 mg in elderly patients with mild-moderate hypertension. QOL improved compared to baseline with no significant difference between the two drugs, thus confirming a positive class effect for calcium antagonists.