Validity of QuickDASH at day of surgery versus day of initial consultation: Does informed consent make a difference?

The trend toward requiring explicit consent from patients participating in observational research increases time and resources required to perform such research. Informed consent introduces the potential for "consent bias"-either through selection bias or through the "Hawthorne effect," where patients may alter responses based upon the awareness of participation in a study, thus potentially limiting its applicability to a generalized orthopedic practice. We hypothesized that administering Quick Disabilities of the Arm, Shoulder, and Hand Questionnaire (QuickDASH) to patients on the day of surgery with informed consent would alter responses in a statistically and clinically meaningful way compared to patients who complete QuickDASH as a quality control measure.

We previously instituted the QuickDASH questionnaire as the standard new patient intake and postoperative questionnaire for quality assurance purposes. We retrospectively reviewed data on a cohort of patients who underwent isolated carpal tunnel release (CTR) who had completed preoperative and postoperative QuickDASH forms without providing consent for study participation. Next, a cohort of patients scheduled to undergo isolated CTR who completed the intake questionnaire was approached on the day of surgery for consent to participate in the study. After obtaining consent but prior to surgery, these patients completed a second questionnaire and then completed a postoperative questionnaire on follow-up at a mean of 8 weeks postoperatively.

Thirty-nine patients and 35 patients were included in the retrospective and prospective cohorts, respectively. No significant differences were observed in age, gender, symptom duration, nerve conduction study/electromyography results, or disease severity between the two groups. We identified no statistically significant difference in preoperative or postoperative QuickDASH score between the retrospective and prospective cohorts (39.8 ± 22.7 vs. 39.7 ± 19.1 preoperatively; 27.3 ± 24.7 vs. 18.7 ± 13.3 postoperatively) or within the prospective cohort before and after obtaining informed consent.

Informed consent did not significantly alter patient responses to the QuickDASH questionnaire. These results suggest that both "opt-in" and "opt-out" approaches to observational research in hand surgery provide results that may be applicable to a generalized orthopedic practice.

This study provides evidence that will inform the interpretation of observational research findings in hand surgery.