Pediatrics/original research
Validity and Reliability of the Verbal Numerical Rating Scale for Children Aged 4 to 17 Years With Acute Pain

https://doi.org/10.1016/j.annemergmed.2017.09.009Get rights and content

Study objective

The Verbal Numerical Rating Scale is the most commonly used self-report measure of pain intensity. It is unclear how the validity and reliability of the scale scores vary across children’s ages. We aimed to determine the validity and reliability of the scale for children presenting to the emergency department across a comprehensive spectrum of age.

Methods

This was a cross-sectional study of children aged 4 to 17 years. Children self-reported their pain intensity, using the Verbal Numerical Rating Scale and Faces Pain Scale–Revised at 2 serial assessments. We evaluated convergent validity (strong validity defined as correlation coefficient ≥0.60), agreement (difference between concurrent Verbal Numerical Rating Scale and Faces Pain Scale–Revised scores), known-groups validity (difference in score between children with painful versus nonpainful conditions), responsivity (decrease in score after analgesic administration), and reliability (test-retest at 2 serial assessments) in the total sample and subgroups based on age.

Results

We enrolled 760 children; 27 did not understand the Verbal Numerical Rating Scale and were removed. Of the remainder, Pearson correlations were strong to very strong (0.62 to 0.96) in all years of age except 4 and 5 years, and agreement was strong for children aged 8 and older. Known-groups validity and responsivity were strong in all years of age. Reliability was strong in all age subgroups, including each year of age from 4 to 7 years.

Conclusion

Convergent validity, known-groups validity, responsivity, and reliability of the Verbal Numerical Rating Scale were strong for children aged 6 to 17 years. Convergent validity was not strong for children aged 4 and 5 years. Our findings support the use of the Verbal Numerical Rating Scale for most children aged 6 years and older, but not for those aged 4 and 5 years.

Introduction

Pain is one of the most common reasons that a child presents to the emergency department (ED).1, 2, 3 The appropriate treatment of pain depends on the ability to readily and accurately assess a child’s pain intensity. The Verbal Numerical Rating Scale is the most frequently used self-report measure of pain intensity in older children and adults with acute pain because of its simplicity and ease of use.4, 5, 6, 7, 8, 9, 10, 11 It involves verbally asking for an estimate of pain intensity, using numbers from 0 (no pain) to 10 (maximal pain), and requires no equipment to administer or score.

Editor’s Capsule Summary

What is already known on this topic

The Verbal Numerical Rating Scale, commonly used to assess pain intensity, is validated for children 8 years and older, but its utility in younger children is unknown.

What question this study addressed

The authors examined validity and reliability of the Verbal Numeric Rating Scale in pediatric emergency department patients aged 4 to 17 years.

What this study adds to our knowledge

In this study of 733 children, convergent validity compared with the validated Faces Pain Scale–Revised, known-groups validity, responsivity, and reliability were strong in all ages, except that convergent validity was not strong for children aged 4 and 5 years.

How this is relevant to clinical practice

The Verbal Numerical Rating Scale may be used to assess pain in most children 6 years and older, but not in those aged 4 and 5 years.

The Verbal Numerical Rating Scale is frequently used for children with acute pain who are aged 8 years or older and has strong validity and reliability in this population.10, 11 However, it is unclear whether the scale has strong psychometric properties in younger children or whether these properties vary according to patient characteristics. For example, children aged 7 years or younger are often considered unable to accurately use the Verbal Numerical Rating Scale because they lack the necessary developmental skills, although recent studies suggest otherwise.12, 13, 14 In addition, the validity and reliability of Verbal Numerical Rating Scale scores may vary according to patient characteristics such as sex, race and ethnicity, or a child’s primary language, which have been shown to be related to a child’s ability to describe pain, as well as his or her perception of, sensitivity to, and experience with pain.15, 16, 17, 18, 19, 20, 21 Therefore, it is important to identify any differences in validity and reliability according to patient characteristics, particularly for children aged 7 years or younger because such findings would affect the generalizability and implementation of the Verbal Numerical Rating Scale for children presenting to the ED with acute pain.

We aimed to determine the validity and reliability of the Verbal Numerical Rating Scale for children presenting to the ED across a comprehensive spectrum of age (4 to 17 years) and other patient characteristics. Our main hypothesis was that children aged 4 to 17 years would demonstrate strong convergent validity (Pearson correlation coefficient ≥0.60) when the Verbal Numerical Rating Scale was compared with the Faces Pain Scale–Revised within older (8 to 17 years) and younger (4 to 7 years) age groups. Our secondary aims were to determine agreement (another measure of convergent validity), known-groups validity, responsivity, and reliability within older and younger age groups; and to determine convergent validity (Pearson correlation coefficient), agreement, known-groups validity, responsivity, and reliability within each year of age for 4 to 7 years for the purpose of identifying a potential lower age limit of validity for the Verbal Numerical Rating Scale. Our exploratory aims were to evaluate these types of validity and reliability in subgroups according to patient characteristics of sex, race or ethnicity, and primary language.

Section snippets

Study Design and Setting

We conducted an observational cross-sectional study in a pediatric ED with an annual census of approximately 55,000 visits. The institutional review board approved this study with verbal informed consent.

Selection of Participants

From April 2014 to March 2016, we enrolled a convenience sample of children aged 4 to 17 years with painful and nonpainful conditions as identified by the triage nurse and confirmed by the study team by asking children themselves whether they had “any pain” or “any hurt.” Children who responded

Characteristics of Study Subjects

We enrolled 760 children; data for 27 children were removed from analyses because they did not understand the Verbal Numerical Rating Scale. The number (and proportion) of children whose data were removed from analysis in each age group was 14 (14%) aged 4 years, 7 (7%) aged 5 years, 5 (5%) aged 6 years, and 1 (1%) aged 7 years. All children aged 8 years or older understood the Verbal Numerical Rating Scale. Figure 2 shows the number of children analyzed for each type of validity and

Limitations

Limitations of the study include enrolling a convenience sample rather than consecutive patients, although our sample included a diverse representation of conditions and a wide distribution of pain intensities. Although selection bias could have occurred because of convenience sampling, bias was less likely because investigators were unable to discern each child’s ability to use or understand the pain scales before being approached for the study. Furthermore, study team members did not enroll

Discussion

In this cross-sectional study, we found that convergent validity, known-groups validity, and responsivity of the Verbal Numerical Rating Scale was strong for children aged 8 to 17 years, as well as for those aged 6 and 7 years. However, the degree of convergent validity was variable for children aged 4 and 5 years. Validity was strong in subgroups based on patient characteristics other than age, except for poor agreement in certain subgroups of race or ethnicity and primary language.

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  • Cited by (0)

    Please see page 692 for the Editor’s Capsule Summary of this article.

    Supervising editor: Kelly D. Young, MD, MS

    Author contributions: DST, CLvB, and PSD conceptualized and designed the study. DST supervised the conduct of the study and data collection. DST and VP undertook recruitment of participating patients. DST and CLvB conducted the statistical analyses for the study. DST drafted the article, and all authors contributed substantially to its revision. DST takes responsibility for the paper as a whole.

    All authors attest to meeting the four ICMJE.org authorship criteria: (1) Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND (2) Drafting the work or revising it critically for important intellectual content; AND (3) Final approval of the version to be published; AND (4) Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.”

    Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist. This publication was supported by the National Center for Advancing Translational Sciences, National Institutes of Health, through grant UL1 TR000040.

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