Enalapril (10 Mg/Day) in Systemic Sclerosis. In: Mallia C, Uitto J, editors. Rheumaderm. Boston: Springer US; 1999. pp. 289-93. [DOI: 10.1007/978-1-4615-4857-7_42]

Lack of efficacy of quinapril on vascular damage in limited cutaneous systemic sclerosis

Gliddon et al. conducted a randomized, double-blind, multicenter, placebo-controlled study to evaluate the efficacy of the angiotensin-converting enzyme inhibitor quinapril for the management of vascular damage in systemic sclerosis (SSc). The trial comprised 213 patients with limited cutaneous SSc or Raynaud's phenomenon (mean age 54 years, 182 females) who were randomly assigned to receive 80 mg/day, or the maximum tolerated dose, of quinapril (n = 105) or placebo (n = 108) for 2-3 years. Patients were assessed every 3 months. The number of new ischemic digital ulcers was recorded as the primary end point, while the frequency of Raynaud's phenomenon episodes, skin score, health status, pulmonary artery pressure and treatments for ischemia were also monitored as secondary end points. There were no detectable differences between patients treated with quinapril and those receiving placebo; however, although no severe adverse effects were observed, patients taking quinapril experienced significantly more adverse effects.

Design and quality considerations for randomized controlled trials in systemic sclerosis

OBJECTIVE

To appraise systematically randomized controlled trials (RCTs) on systemic sclerosis (SSc) in order to determine whether the parameter of study design and its quality may influence the reporting of efficacy for tested interventions.

METHODS

Seventy RCTs were analyzed (1965-2000) in terms of design, patient characteristics, outcomes, and reported results.

RESULTS

Median sample size was 28 patients. Fifty-nine trials were double blind, but only 16 mentioned the randomization mode and only 7 described allocation concealment. There was sufficient information on withdrawals in 37 trials. Larger trials with longer followup scored higher on quality characteristics, but had higher withdrawal rates. Only 8 trials had a followup of more than 1 year. Significant efficacy was less likely to be reported in double-blind studies (P = 0.029) and in studies with larger rates of withdrawal (P = 0.032). Specification of the following parameters improved over time: power calculations (P = 0.0003), outcomes (P = 0.001), and sample size per arm (P = 0.011).

CONCLUSIONS

Several aspects of the quality of design and conduct of SSc RCTs can be improved. Adequately powered trials with longer followup and clear outcomes are needed.