Clinimetric Properties of Self-reported Disability Scales for Whiplash: A Systematic Review for the Whiplash Core Outcome Set (CATWAD)

OBJECTIVES

A core outcomes set (COS) for whiplash-associated disorders (WADs) has been proposed to improve consistency of outcome reporting in clinical trials. Patient-reported disability was one outcome of interest within this COS. The aim of this review was to identify the most suitable tools for measuring self-reported disability in WAD based on clinimetric performance.

METHODS

Database searches took place in 2 stages. The first identified outcome measures used to assess self-reported disability in WAD, and the second identified studies assessing the clinimetric properties of these outcome measures in WAD. Data on the study, population and outcome measure characteristics were extracted, along with clinimetric data. Quality and clinimetric performance were assessed in accordance with the Consensus-based Standards for the Selection of Health Status Measurement Instruments (COSMIN).

RESULTS

Of 19,663 records identified in stage 1 searches, 32 were retained following stage 2 searches and screening. Both the Whiplash Disability Questionnaire and Neck Disability Index performed well in reliability (intraclass correlation coefficient=0.84 to 0.98), construct validity (74% to 82% of hypotheses accepted), and responsiveness (majority of correlations in accordance with hypotheses). Both received Category B recommendations due to a lack of evidence for content validity.

DISCUSSION

This review identified the Neck Disability Index and Whiplash Disability Questionnaire as the most appropriate patient-reported outcome measures (PROMs) for assessing self-reported disability in WAD based on moderate to high-quality evidence for sufficient reliability, construct validity and responsiveness. However, the content validity of these PROMs has yet to be established in WAD, and until this is undertaken, it is not possible to recommend 1 PROM over the other for inclusion in the WAD COS.

Prognostic factors for the improvement of pain and disability following multidisciplinary rehabilitation in patients with chronic neck pain

Background

Recent clinical studies have demonstrated the effectiveness of specific, multidisciplinary, bio-psychosocial, rehabilitation programmes for chronic neck pain. However, prognostic factors for the improvement of pain and disability are mostly unknown. Therefore, the aim of this study was to explore prognostic factors associated with improvements in chronic neck pain following participation in a three-week, multidisciplinary, bio-psychosocial, rehabilitation programme.

Methods

In this observational, prospective cohort study, a total of 112 patients were assessed at the beginning, end, and 6 months following the completion of a multidisciplinary, bio-psychosocial, rehabilitation programme. Inclusion for participation in the rehabilitation programme depended upon an interdisciplinary pain assessment. The primary outcome was neck pain and disability, which was measured using the Northern American Spine Society questionnaire for pain+disability and was quantified with effect sizes (ES). Multivariable linear regression analyses were used to explore potential prognostic factors associated with improvements in pain and disability scores at discharge and at the 6-month follow-up period.

Results

The mean age of the patients was 59.7 years (standard deviation = 10.8), and 70.5% were female. Patients showed improvement in pain+disability at discharge (ES = 0.56; p < 0.001), which was sustained at the 6-month follow-up (ES = 0.56; p < 0.001). Prognostic factors associated with improvement in pain+disability scores at discharge included poor pain+disability baseline scores (partial, adjusted correlation r = 0.414, p < 0.001), older age (r = 0.223, p = 0.024), a good baseline cervical active range-of-motion (ROM) (r = 0.210, p < 0.033), and improvements in the Short-form 36 mental health scale (r = 0.197; p = 0.047) and cervical ROMs (r = 0.195, p = 0.048) from baseline values. Prognostic factors associated with improvements in pain+disability at the 6-month follow-up were similar and included poor pain+disability baseline scores (partial, adjusted correlation r = 0.364, p < 0.001), improvements in the Short-form 36 mental health scale (r = 0.232; p = 0.002), cervical ROMs (r = 0.247, p = 0.011), and better cervical ROM baseline scores. However, older age was not a factor (r = 0.134, p = 0.172).

Conclusions

Future prognostic models for treatment outcomes in chronic neck pain patients should consider cervical ROM and mental health status. Knowledge of prognostic factors may help in the adoption of individualized treatment for patients who are less likely to respond to multidisciplinary rehabilitation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04194-9.

Validity, Reliability, and Responsiveness of the Spanish Version of the OPTIMAL Instrument

BACKGROUND

The Outpatient Physical Therapy Improvement in Movement Assessment Log (OPTIMAL) is a self-report instrument developed to measure the ability to perform mobility actions.

OBJECTIVE

To validate a Spanish version of the OPTIMAL instrument.

DESIGN

Cross-cultural adaptation and validation study.

SETTING

Primary and specialized outpatient care settings.

PARTICIPANTS

Three hundred seven patients beginning physical therapy treatment and 30 subjects from the general population.

METHODS

A 2-part study was designed based on guidelines for cultural adaptation of patient-reported outcome measures.

OUTCOMES

Reliability was estimated by internal consistency (Cronbach α), SE of measurement, and test-retest reliability (intraclass correlation coefficient) at 2 weeks. Confirmatory factor analysis was performed to examine structural validity. The association with the Physical Functioning Subscale was assessed with Spearman correlation coefficients. OPTIMAL scores across different groups were compared with Mann-Whitney U and Kruskal-Wallis tests. Effect size, standardized response mean, and minimal detectable change were determined for responsiveness.

RESULTS

The Spanish version of the OPTIMAL instrument showed a similar structure to the original English questionnaire. Cronbach α was 0.95 for the difficulty and confidence scales. Intraclass correlation coefficient was 0.91 (95% CI 0.87-0.94) for the difficulty scale and 0.90 (95% CI 0.85-0.93) for the confidence scale. The SE of measurement was 5.11 for the difficulty scale and 6.54 for the confidence scale. The association with the Physical Functioning Subscale was strong and significant (P < .001). The 2 scales showed significantly different scores for each of the established patient groups. The effect size was 0.61 (95% CI 0.48-0.74) for the difficulty scale and 0.53 (95% CI 0.38-0.69) for the confidence scale. The standardized response mean was 0.97 (95% CI 0.78-1.13) for the difficulty scale and 0.76 (95% CI 0.48-1.01) for the confidence scale. The minimal detectable change, of a possible score of 100, was 14.2 for the difficulty scale and 18.1 for the confidence scale.

CONCLUSION

The Spanish version of the OPTIMAL has appropriate reliability, validity, and responsiveness and it is an adequate self-report instrument for the assessment of mobility actions.

LEVEL OF EVIDENCE

III.

Does a modified STarT Back Tool predict outcome with a broader group of musculoskeletal patients than back pain? A secondary analysis of cohort data

OBJECTIVES

The STarT Back Tool has good predictive performance for non-specific low back pain in primary care. We therefore aimed to investigate whether a modified STarT Back Tool predicted outcome with a broader group of musculoskeletal patients, and assessed the consequences of using existing risk-group cut-points across different pain regions.

SETTING

Secondary analysis of prospective data from 2 cohorts: (1) outpatient musculoskeletal physiotherapy services (PhysioDirect trial n=1887) and (2) musculoskeletal primary-secondary care interface services (SAMBA study n=1082).

PARTICIPANTS

Patients with back, neck, upper limb, lower limb or multisite pain with a completed modified STarT Back Tool (baseline) and 6-month physical health outcome (Short Form 36 (SF-36)).

OUTCOMES

Area under the receiving operator curve (AUCs) tested discriminative abilities of the tool's baseline score for identifying poor 6-month outcome (SF-36 lower tertile Physical Component Score). Risk-group cut-points were tested using sensitivity and specificity for identifying poor outcome using (1) Youden's J statistic and (2) a clinically determined rule that specificity should not fall below 0.7 (false-positive rate <30%).

RESULTS

In PhysioDirect and SAMBA, poor 6-month physical health was 18.5% and 28.2%, respectively. Modified STarT Back Tool score AUCs for predicting outcome in back pain were 0.72 and 0.79, neck 0.82 and 0.88, upper limb 0.79 and 0.86, lower limb 0.77 and 0.83, and multisite pain 0.83 and 0.82 in PhysioDirect and SAMBA, respectively. Differences between pain region AUCs were non-significant. Optimal cut-points to discriminate low-risk and medium-risk/high-risk groups depended on pain region and clinical services.

CONCLUSIONS

A modified STarT Back Tool similarly predicts 6-month physical health outcome across 5 musculoskeletal pain regions. However, the use of consistent risk-group cut-points was not possible and resulted in poor sensitivity (too many with long-term disability being missed) or specificity (too many with good outcome inaccurately classified as 'at risk') for some pain regions. The draft tool is now being refined and validated within a new programme of research for a broader musculoskeletal population.

TRIAL REGISTRATION NUMBER

ISRCTN55666618; Post results.

Good responsiveness with EuroQol 5-Dimension questionnaire and Short Form (36) Health Survey in 20-69 years old patients with a femoral neck fracture: A 2-year prospective follow-up study in 182 patients

BACKGROUND

EQ-5D and SF-36 are two questionnaires used to measure health related quality of life (HRQoL). The responsiveness of these instruments has previously been evaluated in elderly populations with hip fracture but not in a younger population. The purpose was to evaluate the responsiveness of SF-36 and EQ-5D in a younger population with femoral neck fracture.

METHODS

182 patients aged 20-69 were consecutively included. HRQoL was measured by EQ-5D and SF-36 at 4, 12 and 24 months. Pain and function were measured by Harris Hip Score (HHS) on the same occasions. The responsiveness of EQ-5D and SF-36 was evaluated by calculation of two effect sizes; standardized effect size (SES) and standardized response mean (SRM), and by analysing how changes in score correlated to changes in function and subjective state of health. External responsiveness was also evaluated by calculating receiver operating characteristic curve and area under the curve.

RESULTS

SES was large at four months for both EQ-5D and SF-36 (1.09 and 0.83 respectively) and moderate at the 12- and 24-month follow-ups. The correlation between changes (4-24 months) in HHS and changes in HRQoL were 0.44 for EQ-5D and 0.37 for SF-36. EQ-5D and SF-36 were both more sensitive than HHS in their ability to predict subjective improvements after a hip fracture.

CONCLUSIONS

The effect sizes and the ability to follow and predict the external standard indicates that both EQ-5D and SF-36 have good internal and external responsiveness in this younger population with femoral neck fracture. The generic HRQoL questionnaires were superior to a hip-specific instrument in predicting the patients' subjective feelings of an improved state of health. EQ-5D is simple to administer and shows similar responsiveness as SF-36 and may be sufficient to use as an outcome measure in clinical trials.

Quality of Life and General Health After Elective Surgery for Cervical Spine Pathologies

BACKGROUND:

As part of the Affordable Care Act, health utility metrics are being investigated to define a cost-effective, value-based health care model. EuroQOL-5D (EQ-5D) and Short Form-6D (SF-6D) are commonly used quality-of-life instruments. Domains in the EQ-5D questionnaire are thought to be less responsive in measuring quality of life after cervical surgery.

OBJECTIVE:

To evaluate the validity and responsiveness of SF-6D and EQ-5D in determining health and quality of life after elective cervical spine surgery.

METHODS:

A total of 420 patients undergoing elective cervical spine surgery over a period of 2 years were enrolled in a prospective longitudinal registry. Patient-reported outcomes Neck Disability Index (NDI), EQ-5D, and SF-12 were recorded. Based on previously published equations, SF-6D was calculated using NDI and SF-12 scores. Patients were asked whether “surgery met their expectations” (meaningful improvement). The validity and relative responsiveness of SF-6D (NDI), SF-6D (SF-12), and EQ-5D to discriminate between meaningful and nonmeaningful improvement were calculated.

RESULTS:

Sixty-six percent of patients (277) reported a level of improvement after surgery that met their expectations (meaningful improvement). SF-6D (NDI) (area under the curve [AUC] = 0.69) was a more valid discriminator of meaningful improvement compared with the SF-6D (SF-12) (AUC = 0.65) and EQ-5D (AUC = 0.62). SF-6D (NDI) was also a more responsive measure compared with SF-6D (SF-12) and EQ-5D (standardized response mean difference: 0.66, 0.48, and 0.44, respectively).

CONCLUSION:

SF-6D is a more valid and responsive measure of general health and quality of life compared with EQ-5D. SF-6D derived from disease-specific disability scores was more valid and responsive than that derived from the generic preference-based SF-12. Cost-effective studies should use SF-6D as a measure of QALY after cervical spine surgery.

Accurately measuring the quality and effectiveness of cervical spine surgery in registry efforts: determining the most valid and responsive instruments

BACKGROUND CONTEXT

There is a growing demand to measure the real-world effectiveness and value of care across all specialties and disease states. Prospective registries have emerged as a feasible way to capture real-world care across large patient populations. However, the proven validity of more robust and cumbersome patient-reported outcome instruments (PROi) must be balanced with what is feasible to apply in large-scale registry efforts. Hence, commercial registry efforts that measure quality and effectiveness of care in an attempt to guide quality improvement, pay for performance, or value-based purchasing should incorporate measures that most accurately represent patient-centered improvement.

PURPOSE

We set out to establish the relative validity and responsiveness of common PROi in accurately determining effectiveness of cervical surgery for neck and arm pain in registry efforts.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

Eighty-eight patients undergoing primary anterior cervical discectomy and fusion (ACDF) for neck and arm pain.

OUTCOME MEASURES

Patient-reported outcome measures for pain (numeric rating scale for neck pain [NRS-NP] and arm pain [NRS-AP]), disability (neck disability index [NDI]), general health (short-form 12-item survey physical component summary [SF-12 PCS] and mental component summary [SF-12 MCS]), and quality of life (Euro-Qol-5D [EQ-5D]) were assessed.

METHODS

Eighty-eight patients undergoing primary ACDF for neck and arm pain were entered into a Web-based prospective registry. Baseline and 12-month patient-reported outcomes (NRS-NP, NRS-AP, NDI, SF-12 PCS, SF-12 MCS, and EQ-5D) were assessed. Patients were also asked whether they experienced a level of improvement after ACDF that met their expectation (meaningful improvement). To assess the validity of NRS-NP, NRS-AP, and NDI (measures of pain and disability) to discriminate between meaningful and nonmeaningful improvement and the validity of SF-12 PCS, SF-12 MCS, and EQ-5D (measures of general health and quality of life) to discriminate between meaningful and nonmeaningful improvement, receiver-operating characteristic curves were generated for each outcome instrument. The greater the area under the curve (AUC), the more valid the discriminator. The difference between standardized response means (SRMs) in patients reporting meaningful improvement versus not was calculated to determine the relative responsiveness of each outcome instrument to changes in pain and QOL after surgery.

RESULTS

For pain and disability, both NDI (AUC=0.75) and NRS-AP (AUC=0.74) were valid discriminators of meaningful improvement. Numeric rating scale for neck pain (AUC=0.69) was a poor discriminator. Neck disability index was also most responsive to postoperative improvement (SRM difference 0.78), followed by NRS-AP (SRM difference 0.59) and NRS-NP (SRM difference 0.46). For general health and quality of life, SF-12 PCS (AUC=0.79) was the only valid discriminator of meaningful improvement. Euro-Qol-5D (AUC=0.68) and SF-12 MCS (AUC=0.44) were poor discriminators. Short-form 12 physical component summary (SRM difference 1.08) was also most responsive compared with EQ-5D (SRM difference 0.89) and SF-12 MCS (SRM difference 0.01).

CONCLUSIONS

For pain and disability, NDI is the most valid and responsive measure of improvement after surgery for neck and arm pain. Numeric rating scale for neck pain and NRS-AP are poor substitutes for NDI when measuring effectiveness of care in registry efforts. For health-related quality of life, only SF-12 PCS could accurately discriminate meaningful improvement after cervical surgery and was found to be most valid and responsive. Large-scale registry efforts aimed at measuring effectiveness of cervical spine surgery should use NDI and SF-12 to accurately assess improvements in pain, disability, and quality of life.

Accurately measuring the quality and effectiveness of lumbar surgery in registry efforts: determining the most valid and responsive instruments

BACKGROUND CONTEXT

Prospective registries have emerged as a feasible way to capture real-world care across large patient populations. However, the proven validity of more robust and cumbersome patient-reported outcomes instruments (PROis) must be balanced with what is feasible to apply in large-scale registry efforts.

PURPOSE

To determine the relative validity and responsiveness of common PROis in accurately determining effectiveness of lumbar fusion for degenerative lumbar spondylolisthesis in registry efforts.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

Fifty-eight patients undergoing transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar spondylolisthesis

OUTCOME MEASURES

Patient-reported outcome measures for pain (numeric rating scale for back and leg pain [NRS-BP, NRS-LP]), disability (Oswestry Disability Index [ODI]), general health (Short Form [SF]-12), quality of life (QOL) (EuroQol five dimensions [EQ-5D]), and depression (Zung depression scale [ZDS]) were assessed.

METHODS

Fifty-eight patients undergoing primary TLIF for lumbar spondylolisthesis were entered into an institutional registry and prospectively followed for 2 years. Baseline and 2-year patient-reported outcomes were assessed. To assess the validity of PROis to discriminate between effective and noneffective improvements, receiver operating characteristic curves were generated for each outcomes instrument. An area under the curve (AUC) of ≥0.80 was considered an accurate discriminator. The difference between standardized response means (SRMs) in patients reporting meaningful improvement versus not was calculated to determine the relative responsiveness of each instrument.

RESULTS

For pain and disability, ODI had AUC=0.94, suggesting it as an accurate discriminator of meaningful improvement. Oswestry Disability Index was most responsive to postoperative improvement (SRM difference: 2.18), followed by NRS-BP and NRS-LP. For general health and QOL, SF-12 physical component score (AUC: 0.90), ZDS (AUC: 0.89), and SF-12 mental component score (AUC: 0.85) were all accurate discriminators of meaningful improvement, however, EQ-5D was most accurate (AUC: 0.97). EuroQol five dimensions was also most responsive (SRM difference: 2.83).

CONCLUSIONS

For pain and disability, ODI was the most valid and responsive measure of effectiveness of lumbar fusion. Numeric rating scale-BP and NRS-LP should not be used as substitutes for ODI in measuring effectiveness of care in registry efforts. For health-related QOL, EQ-5D was the most valid and responsive measure of improvement, however, SF-12 and ZDS are valid alternatives with less responsiveness.

Factor analysis of the North American Spine Society outcome assessment instrument: a study based on a spine registry of patients treated with lumbar and cervical disc arthroplasty

BACKGROUND CONTEXT

Studies involving factor analysis (FA) of the items in the North American Spine Society (NASS) outcome assessment instrument have revealed inconsistent factor structures for the individual items.

PURPOSE

This study examined whether the factor structure of the NASS varied in relation to the severity of the back/neck problem and differed from that originally recommended by the developers of the questionnaire, by analyzing data before and after surgery in a large series of patients undergoing lumbar or cervical disc arthroplasty.

STUDY DESIGN/SETTING

Prospective multicenter observational case series.

PATIENT SAMPLE

Three hundred ninety-one patients with low back pain and 553 patients with neck pain completed questionnaires preoperatively and again at 3 to 6 and 12 months follow-ups (FUs), in connection with the SWISSspine disc arthroplasty registry.

OUTCOME MEASURES

North American Spine Society outcome assessment instrument.

METHODS

First, an exploratory FA without a priori assumptions and subsequently a confirmatory FA were performed on the 17 items of the NASS-lumbar and 19 items of the NASS-cervical collected at each assessment time point. The item-loading invariance was tested in the German version of the questionnaire for baseline and FU.

RESULTS

Both NASS-lumbar and NASS-cervical factor structures differed between baseline and postoperative data sets. The confirmatory analysis and item-loading invariance showed better fit for a three-factor (3F) structure for NASS-lumbar, containing items on "disability," "back pain," and "radiating pain, numbness, and weakness (leg/foot)" and for a 5F structure for NASS-cervical including disability, "neck pain," "radiating pain and numbness (arm/hand)," "weakness (arm/hand)," and "motor deficit (legs)."

CONCLUSIONS

The best-fitting factor structure at both baseline and FU was selected for both the lumbar- and cervical-NASS questionnaires. It differed from that proposed by the originators of the NASS instruments. Although the NASS questionnaire represents a valid outcome measure for degenerative spine diseases, it is able to distinguish among all major symptom domains (factors) in patients undergoing lumbar and cervical disc arthroplasty; overall, the item structure could be improved. Any potential revision of the NASS should consider its factorial structure; factorial invariance over time should be aimed for, to allow for more precise interpretations of treatment success.

German translation, cross-cultural adaptation and validation of the whiplash disability questionnaire

BACKGROUND

The Australian Whiplash Disability Questionnaire (WDQ) was cross-culturally translated, adapted, and tested for validity to be used in German-speaking patients. The self-administered questionnaire evaluates actual pain intensity, problems in personal care, role performance, sleep disturbances, tiredness, social and leisure activities, emotional and concentration impairments with 13 questions rated on an 11-point rating scale from zero to ten.

METHODS

In a first part, the Australian-based WDQ was forward and backward translated. In a consensus conference with all translators and health care professionals, who were experts in the treatment of patients with a whiplash associated disorder (WAD), formulations were refined. Original authors were contacted for clarification and approval of the forward-backward translated version. The German version (WDQ-G) was evaluated for comprehensiveness and clarity in a pre-study patient survey by a random sample of German-speaking patients after WAD and four healthy twelve to thirteen year old teenagers. In a second part, the WDQ-G was evaluated in a patient validation study including patients affected by a WAD. Inpatients had to complete the WDQ-G, the North American Spine Society questionnaire (NASS cervical pain), and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) at entry in the rehabilitation centre.

RESULTS

In the pre-study patient survey (response rate 31%) patients rated clarity for title 9.6 ± 0.9, instruction 9.3 ± 1.4 and questions 9.6 ± 0.7, and comprehensiveness for title 9.6 ± 0.7, instruction 9.3 ± 1.4 and questions 9.8 ± 0.4. Time needed to fill in was 13.7 ± 9.0 minutes. In total, 70 patients (47 females, age = 43.4 ± 12.5 years, time since injury: 1.5 ± 2.6 years) were included in the validation study. WDQ-G total score was 74.0 ± 21.3 points (range between 15 and 117 points). Time needed to fill in was 6.7 ± 3.4 minutes with data from 22 patients. Internal consistency was confirmed with Cronbachs's α = 0.89. Concurrent validity showed a highly significant correlation with subscale pain and disability (NASS) at r = 0.74 and subscale pain (SF-36) at r = 0.71.

CONCLUSIONS

The officially translated and adapted WDQ-G can be used in German-speaking patients affected by a WAD to evaluate patients' impairments in different domains. The WDQ-G is a self-administered outcome measure showing a high internal consistency and good concurrent validity.

German version of the whiplash disability questionnaire: reproducibility and responsiveness

BACKGROUND

The Whiplash Disability Questionnaire (WDQ) poses a validated tool for the assessment of patients who experience whiplash-associated disorders. A German translation and cross-cultural adaptation was recently produced and presented high validity and internal consistency. As a follow-up, the presented study tests the translated Whiplash Disability Questionnaire's (WDQ-G) retest reliability and responsiveness to change.

METHODS

The WDQ-G was assessed on three different measurement events: first upon entry (ME1), second four days after entry (ME2), and third at discharge (ME3). Test-retest reliability data from ME1 and ME2 was analysed in a group of stable patients to obtain the intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). To test the instrument's responsiveness, WDQ-G change data were compared to concurrent instruments. The probability of each instrument, to correctly distinguish patients of the stable phase (ME1 to ME2) from patients who deemed to have improved between from ME1 to ME3, was analysed.

RESULTS

In total, 53 patients (35 females, age=45 ± 12.2) were recruited. WDQ-G scores changed from ME1 to ME2 by 5.41 ± 11.6 points in a stable group. This corresponds to a test-retest reliability of ICC=0.91 (95% CI=0.80-0.95) with a SEM of 6.14 points. Minimal Detectable Change, at 95% confidence, was calculated to be 17 points change in scores. Area under Receiver Operator Characteristics of the WDQ-G's responsiveness revealed a probability of 84.6% (95% CI=76.2%-93%) to correctly distinguish between improved and stable patients. Optimal sensitivity (73.2%) and specificity (76.2%) was established at 11-point change.

CONCLUSIONS

High retest reliability and good responsiveness of the WDQ-G support clinical implementation of the translated version. The data suggest, that change in total score greater than eleven points can be interpreted as clinical relevant from a patient's perspective. Minimal Important Change is suggested at 15 points where there is still high specificity and a 90% confidence MDC.

Accurately Measuring Outcomes After Surgery for Adult Chiari I Malformation

BACKGROUND:

There has been a transition to using patient-reported outcome instruments (PROi) to assess surgical effectiveness. However, none of these instruments have been validated for outcomes of adult Chiari I malformation (CMI).

OBJECTIVE:

The aim of this study was to determine the relative validity and responsiveness of various PROi in measuring outcomes after surgery for CMI.

METHODS:

Fifty patients undergoing suboccipital craniotomy for adult CMI were prospectively followed for 1 year. Baseline and 1-year patient-reported outcomes (visual analog scale for head pain and visual analog scale for neck pain, Neck Disability Index [NDI], Headache Disability Index, SF-12, Zung Self-Rating Depression Scale, and EuroQol-5D [EQ-5D]) were assessed. A level of improvement in general health after surgery was defined as meaningful improvement. Receiver-operating characteristic curves were generated to assess the validity of PROi to discriminate between meaningful improvement and not. The difference between standardized response means (SRMs) in patients reporting meaningful improvement vs not as calculated to determine the relative responsiveness of each outcome instrument.

RESULTS:

For pain and disability, the NDI was the most accurate discriminator of meaningful effectiveness (area under the curve: 0.90) and also most responsive to postoperative improvement (standardized response means difference: 1.87). For general health and quality of life, the SF-12 PCS, EQ-5D, and Zung Self-Rating Depression Scale were all accurate discriminators; however, SF-12 Physical Component Scale (SF-12 PCS) and EQ-5D were most accurate. SF-12 PCS was also most responsive.

CONCLUSION:

For pain and disability, NDI is the most valid and responsive measure of improvement after surgery for CMI. For health-related quality of life, SF-12 PCS and EQ-5D are the most valid and responsive measures. NDI with SF-12 or EQ-5D is the most valid in patients with CMI and should be considered in cost-effectiveness studies.