Design of randomized controlled trials in the treatment of leg ulcers: more answers with fewer patients

R. J. Prescott, E. Andrea Nelson, J. J. Dale, D. R. Harper, C. V. Ruckley

Research output: Contribution to journalArticle


Objective: To illustrate the benefit of the factorial design in randomized controlled trials of leg ulcers.
Design: A 2 × 2 × 2 factorial design.
Setting: Hospital leg ulcer clinics in Edinburgh and Falkirk.
Patients: Adults with at least one unhealed leg ulcer of determined origin, present for at least 2 months and greater than 1 cm in diameter.
Interventions: Pentoxifylline (Trental) 400 mg, three times daily, versus placebo
Main outcome measure: Complete healing of all ulcers within 24 weeks.
Results: Of 525 patients screened, 200 pure venous ulcers were randomized (58.5% healed by 24 weeks), 45 complex venous ulcers were randomized (57.8% healed) and 41 arterial patients were randomized (excluding bandaging comparisons) (19.5% healed). There were no interactions between treatments.
Conclusion: The factorial design was feasible to administer and allowed three therapeutic questions to be investigated using the same resources as would have been needed to answer a single question.
Original languageEnglish
Pages (from-to)107-112
Number of pages6
Issue number3
Publication statusPublished - 1 Sep 1998



  • randomised controlled trials
  • design
  • leg ulcers
  • dressings
  • drug therapy

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