Variations in Study Outcomes Relative to Intention-to-treat and Per-protocol Data Analysis Techniques in the Evaluation of Efficacy for Treatment of Venous Leg Ulcers With Dehydrated Human Amnion/Chorion Membrane Allograft

Introduction. Statistical interpretation of data collected in a randomized controlled trial (RCT) is conducted on the intention-to-treat (ITT) and/or the per-protocol (PP) study populations. An ITT analysis is a comparison of treatment groups including all patients as originally allocated after randomization regardless if treatment was initiated or completed. A PP analysis is a comparison of treatment groups including only those patients who completed the treatment as originally allocated, though this is often criticized due to its potential to instill bias. A previous report from an RCT conducted to evaluate the efficacy of dehydrated human amnion/chorion membrane allograft (dHACM) as an adjunct to standard care consisting of moist dressings and multilayer compression in the healing of venous leg ulcers (VLUs) only reported PP study results (n = 109; 52 dHACM, 57 standard care patients) though there were 128 patients randomized: 64 to the dHACM group and 64 to the standard care group. The primary study outcome was the incidence of healing at 12 weeks.

Objective. The purpose of the present study is to report ITT results on all 128 randomized patients and assess if both ITT and PP data analysis arrive at the same conclusion of efficacy for dHACM as a treatment for VLUs.

Results. Healing rates for the ITT and PP populations were 50% and 60% for those receiving dHACM and 31% and 35%, respectively, for those in standard care. Within both ITT and PP analyses, these differences were statistically significant (P =.0473, ITT; P = .0128, PP). Kaplan-Meier plot of time-to-heal within 12 weeks for the ITT and PP populations demonstrated a superior wound healing trajectory for dHACM compared with VLUs treated with standard care alone. 

Conclusions. These data provide clinicians and health policy makers an additional level of assurance regarding the effectiveness of dHACM.

Citation: Bianchi C, Tettelbach W, Istwan N, et al. Variations in study outcomes relative to intention-to-treat and per-protocol data analysis techniques in the evaluation of efficacy for treatment of venous leg ulcers with dehydrated human amnion/chorion membrane allograft. Poster presented at: Symposium on Advanced Wound Care Spring; May 7-11, 2019; San Antonio, TX.

Products: EpiFix, MiMedx Group Inc., Marietta GA

Sponsor: MiMedx Group Inc., Marietta GA

This abstract was not subject to the WOUNDS^® peer-review process.

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