Validation of Digital Visual Analog Scale Pain Scoring With a Traditional Paper-based Visual Analog Scale in Adults

Abstract

Background: The visual analog scale (VAS) is a validated, subjective measure for acute and chronic pain. Scores are recorded by making a handwritten mark on a 10-cm line that represents a continuum between "no pain" and "worst pain."

Methods: One hundred consecutive patients aged ≥18 years who presented with a chief complaint of pain were asked to record pain scores via a paper VAS and digitally via both the laptop computer and mobile phone. Ninety-eight subjects, 51 men (age, 44 ± 16 years) and 47 women (age, 46 ± 15 years), were included. A mixed-model analysis of covariance with the Bonferroni post hoc test was used to detect differences between the paper and digital VAS scores. A Bland-Altman analysis was used to test for instrument agreement between the platforms. The minimal clinically important difference was set at 1.4 cm (14% of total scale length) for detecting clinical relevance between the three VAS platforms. A paired one-tailed Student t-test was used to determine whether differences between the digital and paper measurement platforms exceeded 14% (P < 0.05).

Results: A significant difference in scores was found between the mobile phone-based (32.9% ± 0.4%) and both the laptop computer- and paper-based platforms (31.0% ± 0.4%, P < 0.01 for both). These differences were not clinically relevant (minimal clinically important difference <1.4 cm). No statistically significant difference was observed between the paper and laptop computer platforms. Measurement agreement was found between the paper- and laptop computer-based platforms (mean difference, 0.0% ± 0.5%; no proportional bias detected) but not between the paper- and mobile phone-based platforms (mean difference, 1.9% ± 0.5%; proportional bias detected).

Conclusion: No clinically relevant difference exists between the traditional paper-based VAS assessment and VAS scores obtained from laptop computer- and mobile phone-based platforms.

Conflict of interest statement

Dr. Boutris or an immediate family member is an employee of Zimmer Biomet. Dr. McCulloch or an immediate family member has received research or institutional support from Arthrex and DePuy Synthes; serves as a board member, owner, officer, or committee member of the Journal of Knee Surgery and Orthobullets.com; and is a member of a speakers' bureau or has made paid presentations on behalf of Vericel. Dr. Moreno or an immediate family member has received research or institutional support from 4WEB Medical. Dr. Harris or an immediate family member serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the American Orthopaedic Society for Sports Medicine, Arthroscopy, the Arthroscopy Association of North America, and Frontiers In Surgery; has received research or institutional support from DePuy Synthes and Smith & Nephew; serves as a paid consultant to NIA Magellan, Össur, and Smith & Nephew; is a member of a speakers' bureau or has made paid presentations on behalf of Össur and Smith & Nephew; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from SLACK. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Ms. Delgado, Dr. Lambert, and Mr. Robbins.

Figures

Figure 1

Photographs showing a traditional paper-based visual analog scale (VAS [A]), a digital laptop-based VAS (B), and a mobile phone–based VAS (C).

Figure 2

Graph showing a comparison between mean VAS scores for mobile phone–, laptop-, and paper-based VAS platforms. Data are presented as mean ± SEM. *Significantly different from laptop- and paper-based VAS scores. Type I error was set at α = 0.05. VAS = visual analog scale.

Figure 4

Data plots representing the results of a Bland-Altman analysis for instrument agreement between mobile phone– and paper-based VAS recording (A) and laptop- and paper-based VAS recording (B). Significance for the initial detection of disagreement and post hoc regression to detect proportional bias was set at α = 0.05. VAS = visual analog scale.

Figure 3

Graph showing that the threshold for clinically significant difference (minimal clinically important difference) was set at 14 relative to each VAS scale of 0 to 100. As shown, neither the mobile phone– nor the laptop-based platform VAS scores approached or exceeded that threshold. Data are presented as mean difference scores (±SEM) calculated as difference from the paper-based VAS platform. VAS = visual analog scale.