Calcium channel blockers for primary Raynaud's phenomenon.
BACKGROUND
Calcium channel blockers are the most commonly prescribed drugs for people with primary Raynaud's phenomenon. Primary Raynaud's phenomenon is a common condition characterised by an exaggerated vasospastic response to cold or emotion: classically the digits (fingers and toes) turn white, then blue, then red.


OBJECTIVE
To assess the effects of different calcium channel blockers for primary Raynaud's phenomenon as determined by attack rates, severity scores, participant-preference scores and physiological measurements.


METHODS
The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched February 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 1). In addition the TSC searched clinical trials databases.


METHODS
Randomised controlled trials evaluating the effects of oral calcium channel blockers for the treatment of primary Raynaud's phenomenon.


METHODS
Three review authors independently assessed the trials for inclusion and their quality, and extracted the data. Data extraction included adverse events. We contacted trial authors for missing data.


RESULTS
We included seven randomised trials with 296 participants. Although overall all the trials were classed as being at low or unclear risk of bias, the sample size of the included trials was small and there was unclear reporting of outcomes. Four trials examined nifedipine and the remainder nicardipine. Comparisons were with placebo in six trials and with both dazoxiben and placebo in one trial (only the nifedipine versus placebo data were used within this review). Treatment with oral calcium channel blockers was minimally effective in primary Raynaud's phenomenon at decreasing the frequency of attacks (standardised mean difference of 0.23; 95% confidence interval (CI) 0.08 to 0.38, P = 0.003). This translates to 1.72 (95% CI 0.60 to 2.84) fewer attacks per week on calcium channel blockers compared to placebo. One trial provided details on duration of attacks reporting no statistically significant difference between the nicardipine and placebo groups (no P value reported). Only two trials provided any detail of statistical comparisons of (unvalidated) severity scores between treatment groups: one of these trials (60 participants) reported a mean severity score of 1.55 on placebo and 1.36 on nicardipine, difference 0.2 (95% CI of difference 0 to 0.4, no P value reported) and the other trial (three participants only with primary Raynaud's phenomenon) reported a median severity score of 2 on both nicardipine and placebo treatment (P > 0.999). Participant-preference scores were included in four trials, but in only two were results specific to participants with primary Raynaud's phenomenon, and scoring systems differed between trials: scores differed between treatments in only one trial, in which 33% of participants on placebo and 73% on nifedipine reported improvement in symptoms (P < 0.001). Physiological measurements were included as outcome measures in five trials (different methodologies were used in each): in none of these trials were any statistically significant between-treatment group differences found. Treatment with calcium channel blockers appeared to be associated with a number of adverse reactions, including headaches, flushing and oedema (swelling).


CONCLUSIONS
The randomised controlled trials included in this review provide moderate-quality evidence that oral calcium channel blockers are minimally effective in the treatment of primary Raynaud's phenomenon as measured by the frequency of attacks. However, the results of this review were limited by small sample sizes in the included studies and by variable data quality, particularly with regard to outcome measures.
Centre for Musculoskeletal Research, Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Science Centre, Stopford Building, Oxford Road, Manchester, UK, M13 9PT.
Holly
H
Ennis
Marina E
ME
Anderson
Jack
J
Wilkinson
Ariane L
AL
Herrick
D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D006801:Humans; D009529:Nicardipine / Q000627:therapeutic use; D009543:Nifedipine / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D011928:Raynaud Disease / Q000188:drug therapy*
D002121:Calcium Channel Blockers; D009529:Nicardipine; D009543:Nifedipine