Background: The efficacy and safety of sustained-release nifedipine for the treatment of primary Raynaud phenomenon (RP) has not previously been demonstrated by a randomized, controlled trial. Temperature biofeedback has been studied in patients with primary RP but not in a large multicenter controlled trial or compared with nifedipine therapy.
Objective: To evaluate and compare the effectiveness of sustained-release nifedipine and temperature biofeedback for the treatment of primary RP.
Participants and methods: This is a randomized, controlled clinical trial, double-masked for drug and placebo but not masked for temperature and control biofeedback. It included 313 persons with primary RP as defined by medical history, physical examination findings, normal nailfold capillaries, and a history of 2 or more attacks per day during the previous cold season. Participants were randomized to 1 of 4 treatment groups: (1) sustained-release nifedipine, (2) pill placebo, (3) temperature biofeedback, or (4) control (electromyographic) biofeedback. The primary outcome measure was self-reported, color chart-verified RP attacks during 1 winter month approximately 1 year after initiation of treatment. Secondary outcome measures included verified attacks at 2 months, all attacks at 2 months and 1 year, and quality of life.
Results: Nifedipine-treated participants showed a 66% reduction in verified attacks compared with placebo recipients (P<.001); temperature biofeedback training did not reduce attacks significantly compared with control biofeedback (P = .37). Comparison of nifedipine and temperature biofeedback treatments favored nifedipine use (P = .08); similar results were obtained for the secondary end points. Adverse effects resulted in discontinuation of nifedipine treatment in 15% of participants.
Conclusions: Temperature biofeedback is not better than its control treatment and is inferior to sustained-release nifedipine for treating primary RP, whereas sustained-release nifedipine is a safe and effective treatment for this disease.