Recruitment and inclusion procedures as “pain killers” in clinical trials?

Abstract

H Nothnagel,1–3 M Brown Menard4,5, G Kvarstein,6 AJ Norheim,3 T Weiss,7 C Puta1,8, SD Mist,9 F Musial31Department of Sports Medicine and Health Promotion, Friedrich Schiller University Jena, Jena, Germany; 2Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; 3Department of Community Medicine, The National Research Center for Complementary and Alternative Medicine (NAFKAM), UiT The Arctic University of Norway, Tromsø, Norway; 4Crocker Institute, Kiawah Island, SC, USA; 5School of Integrative Medicine and Health Sciences, Saybrook University, Oakland, CA, USA; 6Pain clinic, University Hospital of Northern Norway, UiT The Arctic University of Norway, Tromsø, Norway; 7Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany; 8Center for Interdisciplinary Prevention of Diseases related to Professional Activities, Friedrich Schiller University, Jena, Germany; 9Oregon Health & Science University, Portland, OR, USABackground: Recruitment and inclusion procedures in clinical trials are time critical. This holds particularly true for studies investigating patients with fluctuating symptom patterns, like those with chronic neck pain. In a feasibility study on neck pain, we found a clinically relevant decrease in pain ratings within the recruitment period. This paper analyses the phenomenon and gives recommendations for recruitment procedures in clinical trials on pain.Methods: Changes in pain intensity scores of 44 chronic neck pain patients (6 males and 36 females; mean age: 45.3±13.2 years) between the first telephone contact and baseline assessment were analyzed. Inclusion criterion was a mean pain intensity of ≥40 on a 0–100 numerical rating scale during the last three months. Statistical analyses were performed using ANOVA and parametric/non-parametric correlation coefficients.Results: Average pain intensity score decreased significantly from 60.3±13.3 at telephone interview to 38.1±21.7 at baseline assessment. This represents a relative change of 36.8%. A weak but significant negative correlation was found between number of days between assessments and pain rating differences. There was a positive correlation between change of pain intensity and the pain level at the first contact, indicating that the decreased pain ratings over time were also dependent on the initial pain rating.Conclusions: The clinically significant changes in pain intensity were weakly related to waiting time and moderately dependent on initial pain intensity, suggesting regression to the mean. The natural course of the disease and the Hawthorne effect are also discussed as contributing factors.Keywords: chronic neck pain, Hawthorne effect, natural course of the disease, regression to the mean, clinical trial, recruitment

Keywords

• Chronic neck pain
• Hawthorne effect
• Natural course of the disease
• Regression to the mean
• Clinical trial
• Recruitment