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Volume :
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33
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Issue :
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02
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Pages :
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260-266
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SHAM-CPAP AS A PLACEBO
Evaluation of Sham-CPAP as a Placebo in CPAP Intervention Studies
George W. Rodway, PhD, RN1; Terri E. Weaver, PhD, RN2,3; Cristina Mancini2; Jacqueline Cater, PhD4; Greg Maislin, MS, MA3,4; Bethany Staley, BA, RPSGT3; Kathleen A. Ferguson MD5; Charles F.P. George, MD5; David A. Schulman, MD, MPH6; Harly Greenberg, MD7; David M. Rapoport, MD8; Joyce A. Walsleben, RN, PhD8; Teofilo Lee-Chiong MD9; Samuel T. Kuna, MD3
1University of Utah College of Nursing and School of Medicine, Salt Lake City, UT; 2Biobehavioral and Health Sciences Division, University of Pennsylvania School of Nursing, Philadelphia, PA; 3Center for Sleep and Respiratory Neurobiology, Division of Sleep Medicine, Dept. of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA; 4Biostatistical Consulting, Wynnewood, PA; 5Division of Respirology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada; 6Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA; 7Division of Pulmonary, Critical Care and Sleep Medicine, North Shore-Long Island Jewish Health System, New Hyde Park, NY; 8Division of Pulmonary and Critical Care Medicine Department of Medicine, New York University School of Medicine, New York, NY; 9Department of Medicine, National Jewish Health, Denver, CO
Study Objectives: To evaluate the use of sham-continuous positive airway pressure (CPAP) treatment as a placebo intervention.
Design and Setting: Analysis of polysomnograms performed in fixed order without sham-CPAP and on the first night of the sham-CPAP intervention in participants in the CPAP Apnea Trial North American Program (CATNAP), a randomized, placebo controlled trial evaluating the effects of CPAP treatment on daytime function in adults with newly diagnosed mild to moderate obstructive sleep apnea (apnea hypopnea index (AHI) 5 - 30).
Participants: The first 104 CATNAP participants randomized to the sham-CPAP intervention arm.
Measurements and Results: Compared to the polysomnographic measures without sham-CPAP, the study on the first night with sham-CPAP had statistically significant differences that suggested a decrease in sleep quality: decreased sleep efficiency, increased arousal index, increased time in stage 1 NREM sleep, and prolonged latency to REM sleep. However, all of these differences had a relatively small effect size. Compared to the polysomnogram without sham-CPAP, the number of hypopneas on the sham-CPAP polysomnogram was significantly increased and the number of apneas significantly decreased. Relatively minor differences in AHI with and without sham-CPAP were present and were dependent on the criteria used to score hypopneas.
Conclusion: Comparison of polysomnograms with and without sham-CPAP revealed differences that, although statistically significant, were small in magnitude and had relatively low effect sizes suggesting minimal clinical significance. The results support the use of sham-CPAP as a placebo intervention in trials evaluating the effects of CPAP treatment in patients with obstructive sleep apnea.
Clinical Trial Information: This paper was a secondary analysis of clinical trial data. CATNAP: CPAP Apnea Trial North American Program, the trial from which the data were obtained, is registered with clinicaltrial.gov. Registration #NCT00089752.
Keywords: CPAP, randomized controlled trial, placebo, sham-CPAP, polysomnogram
Citation: Rodway GW; Weaver TE; Mancini C; Cater J; Maislin G; Staley B; Ferguson KA; George CFP; Schulman DA; Greenberg H; Rapoport DM; Walsleben JA; Lee-Choing T; Kuna ST. Evaluation of sham-CPAP as a placebo in CPAP intervention studies. SLEEP 2010;33(2):260-266.