The Raynaud's Treatment Study (RTS)

Objectives:

To evaluate and compare the effectiveness of sustained-release nifedipine, and the effectiveness of temperature biofeedback, for the treatment of patients with Primary Raynaud's Phenomenon.

Background:

Primary Raynaud's Phenomenon is a peripheral vascular disease of multiple etiologies. Patients with PRP experience episodes, or attacks of severe vasoconstriction. The extremities turn white or blue, often accompanied by numbness and pain which at times can be incapacitating. These attacks are often brought on by cold temperatures or stress. Treatment for PRP include management techniques for avoiding exposures to cold temperatures. In severe cases treatment may include use of vasodilators. Immediate release nifedipine has been shown to reduce the frequency and severity of attacks; however, side-effects also can be severe, inducing the patient to discontinue treatment. Sustained release nifedipine may be a more desirable alternative although the efficacy and adverse effects in patients with PRP has not been shown. Another alternative is non-pharmacological treatment involving temperature biofeedback. Temperature biofeedback uses voluntary control of blood flow and skin temperature, achieved by training, to reduce the frequency and severity of attacks. Temperature biofeedback may be a desirable alternative to vasodilators for patients with a preference for a non-drug treatment or have adverse reactions to vasodilators. Beginning in 1993, 313 patients were enrolled in the NHLBI sponsored, multicenter, Raynaud's Treatment Study and randomly assigned to 1 of 4 treatment groups: sustained-release nifedipine, matching pill placebo control, temperature biofeedback, or biofeedback control (frontalis muscle surface electromyographic biofeedback). Endpoints (verified attacks, all attacks) were collected during a 4 week period directly after a 2 month assessment and a 1 year assessment.

Subjects:

Subjects were eligible if they were 18-75 years of age and reported at least 2 attacks on an average day during the previous cold season. Efforts were made to exclude subjects with secondary Raynaud's Phenomenon during the medical evaluation. A total of 313 subjects were enrolled from 5 clinical centers (113 November 1993 - February 1994 and 200 November 1994 - February 1995).

Conclusions:

Nifedipine treated patients had a 66% reduction in verified attacks compared to placebo patients. There was no significant difference in temperature biofeedback compared to biofeedback control. Nifedipine patients tended to have fewer attacks than temperature biofeedback patients; however, this difference was not statistically significant. Sustained release nifedipine is a safe and effective treatment for PRP and may be superior to temperature biofeedback in reducing the frequency of attacks from PRP. (Arch Intern Med, 2000; 160:1101-1108)