Is less more? A preliminary investigation of the number of response categories in self-reported pain

Principal goals at school: evaluating construct validity and response scaling format

The purpose of the present study was to test the efficacy and appropriateness of the 4-point response option of the Principal's Goals Scale of the SASS (1999-2000) survey. Competing dichotomous models with various conceptualizations were constructed and tested against the original polytomous conceptualization. Participants were 8,524 principals from whom 64% were males and 36% females. Principals' goals were assessed using a 6-item scale anchored across points reflecting proximity to achieving a goal. The original polytomous conceptualization was contrasted to a dichotomous two-pole conceptualization using a model with freely estimated discriminations (two-parameter logistic model, 2PL) as well as the Rasch model assuming equal discrimination parameters. Results indicated that the 2PL dichotomous model provided the most optimal model fit. Furthermore, item-related, and person-related estimates pointed to enhanced accuracy and validity for the dichotomous model conceptualization compared to the polytomous model. It is suggested that a dichotomous scaling system is considered in subsequent measurements of the scale as a means of enhancing the accuracy and validity of the measured trait.

A comparison of brief versus explicit descriptors for verbal rating scales: interrupted time series design

BACKGROUND

Verbal rating scales (VRS) are widely used in patient-reported outcome (PRO) measures. At our institution, patients complete an online instrument using VRSs with a five-point brief response scale to assess symptoms as part of routine follow-up after ambulatory cancer surgery. We received feedback from patients that the brief VRS descriptors such as "mild" or "somewhat" were vague. We added explicit descriptors to our VRSs, for instance, "Mild: I can generally ignore my pain" for pain severity or "Somewhat: I can do some things okay, but most of my daily activities are harder because of fatigue" for fatigue interference. We then compared responses before and after this change was made.

METHODS

The symptoms investigated were pain, fatigue and nausea. Our hypothesis was that the explicit descriptors would reduce overall variance. We therefore compared the coefficient of variation of scores and tested the association between symptoms scores and known predictors thereof. We also compared time to completion between questionnaires with and without the additional descriptors.

RESULTS

A total of 17,500 patients undergoing 21,497 operations were assigned questionnaires in the period before the descriptors were added; allowing for a short transition period, 1,417 patients having 1436 operations were assigned questionnaires with the additional descriptors. Symptom scores were about 10% lower with the additional descriptors but the coefficient of variation was slightly higher. Moreover, the only statistically significant difference between groups for association with a known predictor favored the item without the additional language for nausea severity (p = 0.004). Total completion time was longer when the instrument included the additional descriptors, particularly the first and second time that the questionnaire was completed.

CONCLUSIONS

Adding descriptors to a VRS of post-operative symptoms did not improve scale properties in patients undergoing ambulatory cancer surgery. We have removed the additional descriptors from our tool. We recommend further comparative psychometric research using data from PROs collected as part of routine clinical care.

Comparing the measurement properties of visual analogue and verbal rating scales

PURPOSE

Utilising Rasch analysis on the Keratoconus Outcome Research Questionnaire (KORQ) data, we explored the hypothesis that the KORQ with discrete verbal rating scale (VRS) would demonstrate better psychometric properties and provide less noise in measurement than with a visual analogue scale (VAS).

METHODS

The KORQ is a keratoconus-specific patient-reported outcome measure; it has activity limitation and symptoms scales. The KORQ scales with two different rating scales (VAS and a discrete 4-response VRS) were completed by self-administration by people with keratoconus. For each KORQ scale, Rasch analysis-based psychometric properties were compared between the two versions. Rasch analysis was also used to optimise rating scale functioning when disordered thresholds were observed.

RESULTS

118 (mean age ± SD, 46.4 ± 0.4 years) and 169 (45.4 ± 14.7 years) people completed the KORQ with VAS and VRS, respectively. Both scales demonstrated high measurement precision. However, the VAS rating scale was disordered (6 out of 11 categories dysfunctional) and had two misfitting items. Conversely, the VRS had ordered categories and no misfitting items. For the disordered VAS, ordering was achieved only after collapsing 11 categories into four categories. In comparison to the KORQ with VRS, the repaired VAS had lower measurement precision, test information, variance explained by the measure, poor targeting, and reduced measurement range.

CONCLUSIONS

The KORQ demonstrated superior psychometric properties when measured using a VRS than with a VAS. This illustrates the advantages of verbal rating scales for a patient-reported outcome measurement over a visual analogue scale.

Regenerative Peripheral Nerve Interfaces for the Treatment of Postamputation Neuroma Pain: A Pilot Study

BACKGROUND

Originally designed for prosthetic control, regenerative peripheral nerve interfaces (RPNIs) prevent neuroma formation by providing free muscle grafts as physiological targets for peripheral nerve ingrowth. We report the first series of patients undergoing RPNI implantation for treatment of symptomatic postamputation neuromas.

METHODS

A retrospective case series of all amputees undergoing RPNI implantation for treatment of symptomatic neuromas between November 2013 and June 2015 is presented. Data were obtained via chart review and phone interviews using questions derived from the Patient Reported Outcomes Measurement Information System instruments. Statistical analyses were performed using dependent sample t tests with a significance threshold of P < 0.01.

RESULTS

Forty-six RPNIs were implanted into 16 amputees for neuroma relief (3 upper extremities and 14 lower extremities). Mean age was 53.5 years (6 females and 10 males). All patients participated in postoperative phone interviews at 7.5 ± 3.4 (range: 3-15) months. Patients reported a 71% reduction in neuroma pain and a 53% reduction in phantom pain. Most patients felt satisfied or highly satisfied with RPNI surgery (75%), reporting decreased (56%) or stable (44%) levels of analgesic use. Most patients would strongly recommend RPNI surgery to a friend (88%) and would do it again if given the option (94%). Complications included delayed wound healing (n = 4) and neuroma pain at a different site (n = 2).

CONCLUSIONS

RPNI implantation carries a reasonable complication profile while offering a simple, effective treatment for symptomatic neuromas. Most patients report a significant reduction in neuroma and phantom pain with a high level of satisfaction. The physiological basis for preventing neuroma recurrence is an intriguing benefit to this approach.

Pragmatic characteristics of patient-reported outcome measures are important for use in clinical practice

OBJECTIVES

Measures for assessing patient-reported outcomes (PROs) that may have initially been developed for research are increasingly being recommended for use in clinical practice as well. Although psychometric rigor is essential, this article focuses on pragmatic characteristics of PROs that may enhance uptake into clinical practice.

STUDY DESIGN AND SETTING

Three sources were drawn on in identifying pragmatic criteria for PROs: (1) selected literature review including recommendations by other expert groups; (2) key features of several model public domain PROs; and (3) the authors' experience in developing practical PROs.

RESULTS

Eight characteristics of a practical PRO include: (1) actionability (i.e., scores guide diagnostic or therapeutic actions/decision making); (2) appropriateness for the relevant clinical setting; (3) universality (i.e., for screening, severity assessment, and monitoring across multiple conditions); (4) self-administration; (5) item features (number of items and bundling issues); (6) response options (option number and dimensions, uniform vs. varying options, time frame, intervals between options); (7) scoring (simplicity and interpretability); and (8) accessibility (nonproprietary, downloadable, available in different languages and for vulnerable groups, and incorporated into electronic health records).

CONCLUSION

Balancing psychometric and pragmatic factors in the development of PROs is important for accelerating the incorporation of PROs into clinical practice.

Comparative responsiveness of verbal and numerical rating scales to measure pain intensity in patients with chronic pain

Verbal rating scale (VRS) and numerical rating scale (NRS) are regularly used to assess and monitor pain in chronic pain patients. Although the NRS has been generally preferred, limited comparative responsiveness evidence was reported. This study compared the responsiveness of VRS and NRS measuring current pain and investigated the influence of different references (ie, worst, least, average, and current pain or their composite) on the NRSs' responsiveness. Two hundred fifty-four chronic pain patients attended a 10-day pain self-management program and were assessed with two 6-point VRSs (assessing current pain) and four 11-point NRSs (assessing worst, least, average, and current pain) at pre- and posttreatment. A patient-reported rating of pain improvement was used as the criterion for standardized response mean and receiver operating characteristic curve analyses. Results showed that the VRSs and NRSs exhibited small responsiveness in all patients, but the magnitude of responsiveness became moderate to large in patients with improved pain. However, in patients with pain improvements, the NRS current pain item and composite score (made up of the 4 pain items) were found to have significantly larger responsiveness and greater discriminatory ability to detect the presence of improvement than other current pain VRSs and the NRSs assessing worst, least, and average pain. Potential implications for clinical practice are discussed.

PERSPECTIVE

This study shows that the current pain and composite NRSs were more responsive than the current pain VRSs and the NRSs measuring other individual pain references in patients with improved pain, undertaking a short-term, self-management program. The results help inform the selection of pain intensity measures in studies using similar types of intervention.