Translation, cross-cultural adaptation and psychometric properties of the Nepali versions of numerical pain rating scale and global rating of change

BackgroundPain intensity and patients’ impression of global improvement are widely used patient-reported outcome measures (PROMs) in clinical practice and research. They are commonly assessed using the Numerical Pain Rating Scale (NPRS) and Global Rating of Change (GROC) questionnaires. The GROC is essential as an anchor for evaluating the psychometric properties of PROMs. Both of these PROMs are translated to many languages and have shown excellent psychometric properties. Their availability in Nepali would facilitate pain research and cross-cultural comparison of research findings. Therefore, the objectives of this study were to translate and cross-culturally adapt the NPRS and GROC into Nepali and to assess the psychometric properties of the Nepali version of the NPRS (NPRS-NP).MethodsAfter translating and cross-culturally adapting the NPRS and GROC into Nepali using recommended guidelines, NPRS-NP was administered to 104 individuals with musculoskeletal pain twice. The Nepali version of the GROC (GROC-NP) was administered at the follow-up for anchor-based assessment. (1) Test-retest reliability and minimum detectable change (MDC) among the stable group, (2) construct validity (by single sample t-test within the improved group and independent sample t-test between groups), and (3) concurrent validity were assessed. Receiver operating characteristic (ROC) curves were plotted to determine the responsiveness of the NPRS-NP using the area under the curve (AUC), and minimum important changes (MIC) for small, medium and large improvements.ResultsSignificant cultural adaptations were required to obtain relevant Nepali versions of both the NPRS and GROC. The NPRS-NP showed excellent test-retest reliability and a MDC of 1.13 points. NP demonstrated a good construct validity by significant within-group difference in mean of NPRS score- t(63)= 7.57, P < 0.001 and statistically significant difference of mean score- t(98)= -4.24, P < .001 between the stable and improved groups. It demonstrated moderate concurrent correlation with the GROC-NP; r = 0.43, P < 0.01. Responsiveness of the NPRS-NP was shown at three levels with AUC = 0.68–0.82, and MIC = 1.17–1.33.ConclusionsThe NPRS and GROC were successfully translated and culturally adapted into Nepali. The NPRS-NP demonstrated good reliability, validity and responsiveness in assessing musculoskeletal pain intensity in a Nepali population.

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Single-group repeated-measures design.



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Patients (N=137) presenting to PT with a primary report of neck pain.



Not applicable.



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Both the NDI and NRS exhibit fair to moderate test-retest reliability in patients with mechanical neck pain. Both instruments also showed adequate responsiveness in this patient population. However, the MCID required to be certain that the change in scores has surpassed a level that could be contributed to measurement error for the NDI was twice that which has previously been reported. Therefore the ongoing analyses of the properties of the NDI in a patient population with neck pain are warranted.

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abstract: &NA; The purpose of this study was to determine the levels of change on standard pain scales that represent clinically important differences to patients. Data from analgesic studies are often difficult to interpret because the clinical importance of the results is not obvious. Differences between groups, as summarized by a change in mean values over time, can be difficult to apply to clinical care. Baseline scores vary widely and group mean differences could reflect large changes in a few patients, small changes in many patients, or any combination of these outcomes. Determination of the proportion of patients who have a clinically important improvement in their pain would provide a more interpretable result with direct clinical implications. However, determining a clinically important outcome requires information about the degree of change over time that is clinically important. Data from the titration phase of a multiple cross‐over randomized clinical trial of oral transmucosal fentanyl citrate (OTFC) for the treatment of cancer‐related breakthrough pain were re‐analyzed to examine the differences in pain scores between treatment episodes that did and did not yield adequate pain relief. The scales evaluated were absolute pain intensity difference (PID, 0–10 scale), percentage pain intensity difference (PID%, 0–100% scale), pain relief (PR, 0 (none), 1 (slight), 2 (moderate), 3 (lots), 4 (complete)), sum of the pain intensity difference (SPID over 60 min), percentage of maximum total pain relief (% Max TOTPAR over 60 min), and global medication performance (0 (poor), 1 (fair), 2 (good), 3 (very good), 4 (excellent)). Adequate relief was defined by the patient's decision not to use another dose of opioid medication as a rescue, in addition to the study medication, to treat each painful episode. One hundred thirty OTFC naive patients contributed data on 1268 episodes of breakthrough pain. The scales that were converted to a percentage change yielded the best accuracy in predicting adequate relief, with balanced sensitivity and specificity. The best cut‐off point for both the % Max TOTPAR and the PID% was 33%. The best cut‐off points for the absolute scales were absolute pain intensity difference of 2, pain relief of 2 (moderate), and SPID of 2. The global medication performance of 2 (good) had excellent values as well. This study presents data‐derived cut‐off points for the changes in several pain scales, each reflecting the clinically important improvement for patients treating breakthrough cancer pain episodes with OTFC. Confirmation in other patient populations and different pain syndromes will be needed. The use of consistent clinically important cut‐off points as the primary outcome in future pain therapy clinical trials will enhance their validity, comparability, and clinical applicability.

title: Minimal Clinically Important Change for Pain Intensity, Functional Status, and General Health Status in Patients With Nonspecific Low Back Pain
abstract: To estimate the Minimal Clinically Important Change (MCIC) of the pain intensity numerical rating scale (PI-NRS), the Quebec Back Pain Disability Scale (QBPDS), and the Euroqol (EQ) in patients with low back pain.  MCIC can provide valuable information for researchers, healthcare providers, and policymakers.  Data from a randomized controlled trial with 442 patients with low back pain were used. The MCIC was estimated over a 12-week period, and three different methods were used: 1) mean change scores, 2) minimal detectable change, and 3) optimal cutoff point in receiver operant curves. The global perceived effect scale (GPE) was used as an external criterion. The effect of initial scores on the MCIC was also assessed.  The MCIC of the PI-NRS ranged from 3.5 to 4.7 points in (sub)acute patients and 2.5 to 4.5 points in chronic patients with low back pain. The MCIC of the QBPDS was estimated between 17.5 to 32.9 points and 8.5 to 24.6 points for (sub)acute and chronic patients with low back pain. The MCIC for the EQ ranged from 0.07 to 0.58 in (sub)acute patients and 0.09 to 0.28 in patients with chronic low back pain.  Reporting the percentage of patients who have made a MCIC adds to the interpretability of study results. We present a range of MCIC values and advocate the choice of a single MCIC value according to the specific context.

title: Words that describe chronic musculoskeletal pain: implications for assessing pain quality across cultures
abstract: People from different cultures who speak different languages may experience pain differently. This possible variability has important implications for evaluating the validity of pain quality measures that are directly translated into different languages without cultural adaptations. The aim of this study was to evaluate the impact of language and culture on the validity of pain quality measures by comparing the words that individuals with chronic pain from Nepal use to describe their pain with those used by patients from the USA.  A total of 101 individuals with chronic musculoskeletal pain in Nepal were asked to describe their pain. The rates of the different pain descriptor domains and phrases used by the Nepali sample were then compared to the published rates of descriptors used by patients from the USA. The content validity of commonly used measures for assessing pain quality was then evaluated.  While there was some similarity between patients from Nepal and the USA in how they describe pain, there were also important differences, especially in how pain quality was described. For example, many patients from Nepal used metaphors to describe their pain. Also, the patients from Nepal often used a category of pain descriptor – which describes a physical state – not used by patients from the USA. Only the original McGill Pain Questionnaire was found to have content validity for assessing pain quality in patients from Nepal, although other existing pain quality measures could be adapted to be content valid by adding one or two additional descriptors, depending on the measure in question.  The findings indicate that direct translations of measures that are developed using samples of patients from one country or culture are not necessarily content valid for use in other countries or cultures; some adaptations may be required in order for such measures to be most useful in new language and culture.

title: Choice of external criteria in back pain research: Does it matter? Recommendations based on analysis of responsiveness
abstract: Understanding a change score is indispensable for interpretation of results from clinical studies. One way of determining the relevance of change scores is through the use of transition questions that assesses patients’ retrospective perception of treatment effect. Unfortunately, results from studies using transition questions are difficult to compare since wording of questions and definitions of important improvements vary between studies. The objectives of this study were to determine the consequence of using different transition questions on pain and disability measures and make proposals for a standardised use of such questions. Two hundred and thirty‐three patients with low back pain and/or leg pain were recruited. Participants were followed over an 8‐week period and randomised to two groups receiving a 7‐ (TQ1) and 15‐point (TQ2) transition question, respectively, in addition to a numeric rating scale evaluating the importance of the perceived change. Four external criteria were generated using both stringent and less stringent standards to dichotomise patients. Discrimination was determined using area under the receiver operating characteristic curve (ROCauc) and responsiveness using standardised response mean (SRM). Results demonstrated small variations in ROCauc across the external criteria for all outcome measures. 7% more patients were classified as improved in the group receiving the 15‐point TQ compared to the 7‐point TQ (stringent standard). SRMs were higher for the retrospective TQs in primary sector patients compared to the serial measures with no difference between TQ1 and TQ2. On the basis of our findings we have outlined a proposal for a standardised use of transition questions.

title: The psychometric properties of an Arabic numeric pain rating scale for measuring osteoarthritis knee pain
abstract: The aims of this study were to translate the numeric rating scale (NRS) into Arabic and to evaluate the test–retest reliability and convergent validity of an Arabic Numeric Pain Rating Scale (ANPRS) for measuring pain in osteoarthritis (OA) of the knee.  The English version of the NRS was translated into Arabic as per the translation process guidelines for patient-rated outcome scales. One hundred twenty-one consecutive patients with OA of the knee who had experienced pain for more than 6 months were asked to report their pain levels on the ANPRS, visual analogue scale (VAS), and verbal rating scale (VRS). A second assessment was performed 48 h after the first to assess test–retest reliability. The test–retest reliability was calculated using the intraclass correlation coefficient (ICC2,1). The convergent validity was assessed using Spearman rank correlation coefficient. In addition, the minimum detectable change (MDC) and standard error of measurement (SEM) were also assessed.  The repeatability of ANPRS was good to excellent (ICC 0.89). The SEM and MDC were 0.71 and 1.96, respectively. Significant correlations were found with the VAS and VRS scores (p <0.01).  The Arabic numeric pain rating scale is a valid and reliable scale for measuring pain levels in OA of the knee. ANPRS) is a reliable and valid instrument for measuring pain in osteoarthritis (OA) of the knee, with psychometric properties in agreement with other widely used scales. The ANPRS is well correlated with the VAS and NRS scores in patients with OA of the knee. The ANPRS appears to measure pain intensity similar to the VAS, NRS, and VRS and may provide additional advantages to Arab populations, as Arabic numbers are easily understood by this population.

title: Using ROC Curves to Choose Minimally Important Change Thresholds when Sensitivity and Specificity Are Valued Equally: The Forgotten Lesson of Pythagoras. Theoretical Considerations and an Example Application of Change in Health Status
abstract: curves are being used to identify Minimally Important Change (MIC) thresholds on scales that measure a change in health status. In quasi-continuous patient reported outcome measures, such as those that measure changes in chronic diseases with variable clinical trajectories, sensitivity and specificity are often valued equally. Notwithstanding methodologists agreeing that these should be valued equally, different approaches have been taken to estimating MIC thresholds using ROC curves.  We aimed to compare the different approaches used with a new approach, exploring the extent to which the methods choose different thresholds, and considering the effect of differences on conclusions in responder analyses.  Using graphical methods, hypothetical data, and data from a large randomised controlled trial of manual therapy for low back pain, we compared two existing approaches with a new approach that is based on the addition of the sums of squares of 1-sensitivity and 1-specificity.  There can be divergence in the thresholds chosen by different estimators. The cut-point selected by different estimators is dependent on the relationship between the cut-points in ROC space and the different contours described by the estimators. In particular, asymmetry and the number of possible cut-points affects threshold selection.  Choice of MIC estimator is important. Different methods for choosing cut-points can lead to materially different MIC thresholds and thus affect results of responder analyses and trial conclusions. An estimator based on the smallest sum of squares of 1-sensitivity and 1-specificity is preferable when sensitivity and specificity are valued equally. Unlike other methods currently in use, the cut-point chosen by the sum of squares method always and efficiently chooses the cut-point closest to the top-left corner of ROC space, regardless of the shape of the ROC curve.

title: Likert scales, levels of measurement and the “laws” of statistics
abstract: Reviewers of research reports frequently criticize the choice of statistical methods. While some of these criticisms are well-founded, frequently the use of various parametric methods such as analysis of variance, regression, correlation are faulted because: (a) the sample size is too small, (b) the data may not be normally distributed, or (c) The data are from Likert scales, which are ordinal, so parametric statistics cannot be used. In this paper, I dissect these arguments, and show that many studies, dating back to the 1930s consistently show that parametric statistics are robust with respect to violations of these assumptions. Hence, challenges like those above are unfounded, and parametric methods can be utilized without concern for “getting the wrong answer”.

title: Validity of four pain intensity rating scales
abstract: The validity of 4 common pain intensity measures is supported, although the 0–10 Numerical Rating Scale and Visual Analogue Scale evidenced the most responsivity.  The Visual Analogue Scale (VAS), Numerical Rating Scale (NRS), Verbal Rating Scale (VRS), and the Faces Pain Scale‐Revised (FPS‐R) are among the most commonly used measures of pain intensity in clinical and research settings. Although evidence supports their validity as measures of pain intensity, few studies have compared them with respect to the critical validity criteria of responsivity, and no experiment has directly compared all 4 measures in the same study. The current study compared the relative validity of VAS, NRS, VRS, and FPS‐R for detecting differences in painful stimulus intensity and differences between men and women in response to experimentally induced pain. One hundred twenty‐seven subjects underwent four 20‐second cold pressor trials with temperature order counterbalanced across 1°C, 3°C, 5°C, and 7°C and rated pain intensity using all 4 scales. Results showed statistically significant differences in pain intensity between temperatures for each scale, with lower temperatures resulting in higher pain intensity. The order of responsivity was as follows: NRS, VAS, VRS, and FPS‐R. However, there were relatively small differences in the responsivity between scales. A statistically significant sex main effect was also found for the NRS, VRS, and FPS‐R. The findings are consistent with previous studies supporting the validity of each scale. The most support emerged for the NRS as being both (1) most responsive and (2) able to detect sex differences in pain intensity. The results also provide support for the validity of the scales for use in Portuguese samples.

title: A comparison of three self-report pain scales in adults with acute pain.
abstract: Several pain rating methods are used to quantify pain. Although these instruments have been extensively studied, their inter-agreement, especially in emergency department (ED) settings, has yet to be determined.



This study was designed to assess the agreement between Visual Analog Scale (VAS), Color Analog Scale (CAS), and verbally administered Numeric Rating Scale (NRS) in the emergency setting.



A sample of 150 adult patients presenting with acute pain to two EDs was recruited. Patients' pain severity at presentation, 30 and 60 min later was assessed using the three pain scales. The agreement between pain scales was assessed using Bland-Altman method and Spearman correlation. We described a composite measure to serve as the gold standard and to be compared with each score. Factor analysis was also performed to assess the underlying construct.



Spearman correlation coefficients between NRS and CAS, NRS and VAS, and CAS and VAS were 0.95, 0.94, and 0.94, respectively (p < 0.001). On a scale of 0 to 10, the 95% limits of agreement between the paired NRS and VAS, VAS and CAS, and CAS and NRS as measured by Bland-Altman method ranged from -2.0 to 2.6, from -2.7 to 2.0, and from -2.1 to 2.0, respectively. The Kaiser-Meyer-Oklin measure of sampling adequacy was 0.785 and Bartlett's test for sphericity was significant (p < 0.001).



The three pain scales were strongly correlated at all time periods. The findings suggest that NRS, CAS, and VAS can be interchangeably applied for acute pain measurement in adult patients.