Minimal Important Difference Values Research Articles

Minimal important difference of the 12-item World Health Organization Disability Assessment Schedule (WHODAS) 2.0 in persons with chronic low back pain

BackgroundThe World Health Organization Disability Assessment Schedule 2.0 12-item survey (WHODAS-12) is a questionnaire developed by the WHO to measure functioning across health conditions, cultures, and settings. WHODAS-12 consists of a subset of the 36 items of WHODAS-2.0 36-item questionnaire. Little is known about the minimal important difference (MID) of WHODAS-12 in persons with chronic low back pain (LBP), which would be useful to determine whether rehabilitation improves functioning to an extent that is meaningful for people experiencing the condition. Our objective was to estimate an anchor-based MID for WHODAS-12 questionnaire in persons with chronic LBP.MethodsWe analyzed data from two cohort studies (identified in our previous systematic review) conducted in Europe that measured functioning using the WHODAS-36 in adults with chronic LBP. Eligible participants were adults with chronic LBP with scores on another measure as an anchor to indicate participants with small but important changes in functioning over time [Short-form-36 Physical Functioning (SF36-PF) or Oswestry Disability Index (ODI)] at baseline and follow-up (study 1: 3-months post-treatment; study 2: 1-month post-discharge from hospital). WHODAS-12 scores were constructed as sums of the 12 items (scored 0–4), with possible scores ranging from 0 to 48. We calculated the mean WHODAS-12 score in participants who achieved a small but meaningful improvement on SF36-PF or ODI at follow-up. A meaningful improvement was an MID of 4–16 on ODI or 5–16 on SF36-PF.ResultsOf 70 eligible participants in study 1 (mean age = 54.1 years, SD = 14.7; 69% female), 18 achieved a small meaningful improvement based on SF-36 PF. Corresponding mean WHODAS-12 change score was − 3.22/48 (95% CI -4.79 to -1.64). Of 89 eligible participants in study 2 (mean age = 65.5 years, SD = 11.5; 61% female), 50 achieved a small meaningful improvement based on ODI. Corresponding mean WHODAS-12 change score was − 5.99/48 (95% CI − 7.20 to -4.79).ConclusionsUsing an anchor-based approach, the MID of WHODAS-12 is estimated at -3.22 (95% CI -4.79 to -1.64) or -5.99 (95% CI − 7.20 to -4.79) in adults with chronic LBP. These MID values inform the utility of WHODAS-12 in measuring functioning to determine whether rehabilitation or other health services achieve a minimal difference that is meaningful to patients with chronic LBP.

Responsiveness of the late life disability instrument to pulmonary rehabilitation in people with COPD

PurposeTo establish the responsiveness of the disability component of the Late Life Function and Disability Instrument (LLDI) and its Computer Adaptive Test (LLDI-CAT) in people with chronic obstructive pulmonary disease (COPD). MethodParticipants completed the LLDI, LLDI-CAT and measures of physical function, health-related quality of life (HRQOL) and symptom severity before and after pulmonary rehabilitation (PR), and global rating of change (GRC) scales at the end of PR. Responsiveness was explored by calculating correlations between LLDI and LLDI-CAT change scores and change scores on the other measures, and calculating the area under the receiver operating characteristic curve (AUC) for the ability of the LLDI and LLDI-CAT to discriminate between participants who were improved versus unchanged. We hypothesized fair correlations (−0.3 to −0.5 or 0.3 to 0.5) with other measures and considered an AUC≥0.7 acceptable. Minimal important differences (MIDs) were estimated using anchor- and distribution-based approaches. ResultsFifty participants (mean (SD) age 69.8 (7.9) years) completed the study. Only the limitation dimension of the LLDI showed improvement at follow-up (z = 2.4, p = 0.018) and was able to discriminate between participants who were improved versus unchanged (AUC 0.7 (95% CI 0.6–0.9)). Correlations between change scores were as hypothesized between the participation measures and measures of at least two other constructs. ConclusionThis study provides MID values for the LLDI and LLDI-CAT to support their clinical application. The limitation dimension of the LLDI appears to be particularly responsive to PR in people with COPD.

The minimal important difference of six-minute walk test in subjects with chronic pulmonary aspergillosis treated with six-months of oral itraconazole.

The minimal important difference of six-minute walk test in subjects with chronic pulmonary aspergillosis treated with six-months of oral itraconazole.

Minimal important difference and patient acceptable symptom state for common outcome instruments in patients with a closed humeral shaft fracture - analysis of the FISH randomised clinical trial data

BackgroundTwo common ways of assessing the clinical relevance of treatment outcomes are the minimal important difference (MID) and the patient acceptable symptom state (PASS). The former represents the smallest change in the given outcome that makes people feel better, while the latter is the symptom level at which patients feel well.MethodsWe recruited 124 patients with a humeral shaft fracture to a randomised controlled trial comparing surgery to nonsurgical care. Outcome instruments included the Disabilities of Arm, Shoulder, and Hand (DASH) score, the Constant-Murley score, and two numerical rating scales (NRS) for pain (at rest and on activities). A reduction in DASH and pain scores, and increase in the Constant-Murley score represents improvement. We used four methods (receiver operating characteristic [ROC] curve, the mean difference of change, the mean change, and predictive modelling methods) to determine the MID, and two methods (the ROC and 75th percentile) for the PASS. As an anchor for the analyses, we assessed patients’ satisfaction regarding the injured arm using a 7-item Likert-scale.ResultsThe change in the anchor question was strongly correlated with the change in DASH, moderately correlated with the change of the Constant-Murley score and pain on activities, and poorly correlated with the change in pain at rest (Spearman’s rho 0.51, -0.40, 0.36, and 0.15, respectively).Depending on the method, the MID estimates for DASH ranged from -6.7 to -11.2, pain on activities from -0.5 to -1.3, and the Constant-Murley score from 6.3 to 13.5.The ROC method provided reliable estimates for DASH (-6.7 points, Area Under Curve [AUC] 0.77), the Constant-Murley Score (7.6 points, AUC 0.71), and pain on activities (-0.5 points, AUC 0.68).The PASS estimates were 14 and 10 for DASH, 2.5 and 2 for pain on activities, and 68 and 74 for the Constant-Murley score with the ROC and 75th percentile methods, respectively.ConclusionOur study provides credible estimates for the MID and PASS values of DASH, pain on activities and the Constant-Murley score, but not for pain at rest. The suggested cut-offs can be used in future studies and for assessing treatment success in patients with humeral shaft fracture.Trial registrationClinicalTrials.gov NCT01719887, first registration 01/11/2012.

Toward a rigorous assessment of the statistical performances of methods to estimate the Minimal Important Difference of Patient-Reported Outcomes: A protocol for a large-scale simulation study.

Interpreting observed changes over time in Patient-Reported Outcomes (PRO) measures is still considered a challenge. Indeed, concluding an observed change at group level is statistically significant does not necessarily equate this change is meaningful from the perspective of the patient. To help interpret within and/or between group changes in the measure over time, the estimation of the Minimal Important Difference (MID) of the instrument - the smallest value that patients consider as a perceived change - is useful. In the last 30years, a plethora of methods and estimators have been proposed to derive this MID value using clinical data from sample of patients. MIDs for hundreds of PROs have been estimated, with frequently a substantial variability in the results depending on the method used. Nonetheless, a rigorous assessment of the statistical performances of numerous proposed methods for estimating MIDs by experimental design such as Monte-Carlo study has never been performed. The purpose of this paper is to thoroughly depict a protocol for a large-scale simulation study designed to investigate the statistical performances, especially bias against a true populational value, of the common proposed estimators for MID. This paper depicts how investigated methods and estimators were retained after the conduct of a systematic review, the design of a conceptual model that formally defines what is the true populational MID value and the translation of the conceptual model into a model allowing the simulation of responses of items to a hypothetical PRO at two times of measurement along with the response to a Patient Global Rating of Change at the second time under the constraint of a known true MID value. A statistical analysis plan is depicted in order to conclude if working hypotheses on what could be appropriate MID estimators will be verified. Strengths, assumptions, and limits of the simulation model are exposed. Finally, we show how this protocol could be the basis for fostering future methodological research on the issue of interpreting changes in PRO measures.

The Meaning and Reliability of Minimal Important Differences (MIDs) for Clinician-Reported Outcome Measures (ClinROMs) in Dermatology-A Scoping Review.

Background: Clinician-reported outcome measures (ClinROMs) are frequently used in clinical trials and daily practice to evaluate the disease status and evolution of skin disorders. The minimal important difference (MID) represents the smallest difference that decreases the disease impact enough to make a treatment change worthwhile for patients. As no clear guidance exists on the preferred method to calculate MIDs for ClinROMs, we evaluated how the published values for different skin disorders should be interpreted. Methods: A systematic search was performed for MIDs of ClinROMs that focus on skin disorders and/or symptoms. The results of the questions in the credibility instrument for MIDs of Devji et al., 2020 were analyzed to gain insights into the meaning of these MIDs. Results: 29 MIDs were identified. The most common skin diseases were atopic dermatitis/eczema, followed by bullous disorders and psoriasis. A minimal important difference from the patients’ perspective was determined in 31% of the cases. However, in 41.4% of the cases, it concerned a substantial rather than a minimal difference in disease severity rated by physicians. Over half (55.1%) of the studies contained an inadequate number of patients (n < 150). MID values increased substantially in patients with severe compared to mild disease. Conclusions: MIDs of ClinROMs for skin disorders should be carefully interpreted due to the substantial differences in methodology between the studies. There is an urgent need for a consensus method to report reliable MIDs. Otherwise, this lack of uniformity could not only affect the design and conclusion of clinical trials but also skew treatment decisions.

The CARe Burn Scale—Adult Form: Identifying the Responsiveness and Minimal Important Difference (MID) Values of a Patient Reported Outcome Measure (PROM) to Assess Quality of Life for Adults with a Burn Injury

The CARe Burn Scales are a suite of burn-specific PROMs for adults, children, young people, and parents affected by burns. This study aimed to determine the responsiveness and minimal important difference (MID) values of the Adult Form for use in adult burn care and research. Participants were recruited by 11 UK Burn Services. They completed online or paper versions of the CARe Burn Scale –Adult Form and a set of appropriate comparison validated measures and anchor questions at baseline (T1, up to 4 weeks post-burn), 3 months (T2), and 6 months post-burn (T3). A total of 269 participants took part at baseline and 226 (84%) were retained at the 6-month follow-up. Spearman’s correlation analysis and effect sizes based on Cohen’s d thresholds were reported and MID values calculated. MID values were created for all subscales and ranged from 4–15. The CARe Burn Scale–Adult Form is responsive to change over time and can therefore be used to reliably inform the management of adults’ burn injury treatment and recovery. It is freely available for clinical and research use.

The Minimal Important Difference of the Fecal Incontinence Quality of Life (FIQL) Questionnaire for Patients with Posterior Compartment Prolapse: A Prospective Cohort Study.

Objectives: The minimally important difference (MID) of the Fecal Incontinence Quality of Life (FIQL) scale has never been determined. Thus, in this study, we aimed to estimate the MID of the Japanese FIQL for patients with posterior compartment prolapse (PCP). Methods: For 3-months after surgery, we followed a prospective cohort of 136 patients with PCP combined with fecal incontinence (FI) who had undergone ventral rectopexy between 2012 and 2018. Usable data from 114 patients were analyzed. Patients have both completed the FIQL and the 36-Item Short Forum Health Survey (SF-36) before and after surgery. Distribution-based MID values were estimated at 1/2 SD and the standard error of measurement (SEM) for domain and total scores across time points. Changes in the domain scores anchored to changes in a SF-36 overall health assessment question were used to estimate anchor-based MID. To be interpreted as true change, the median, anchor-based MID values that were greater than the corresponding SEM were proposed as estimates of the MID for the FIQL. Results: Distribution-based MID of 1/2 SD for each domain and total score ranged between 0.3 and 0.4, whereas SEM ranges were between 0.2 and 0.3. The anchor-based approach resulted in the median MID estimates of 0.4 to 1.0. Final estimates of MID for each FIQL and total score were as follows: lifestyle (0.6-1.1), coping/behavior (0.8-1.4), depression/self-perception (0.4-0.8), embarrassment (1.0-1.6), and total score (0.7-1.1). Conclusions: The results provide a basis for clinically important differences in FIQL scores after surgery for patients with PCP and FI.

Vascular Quality of Life Questionnaire-6 Before and After Supervised Exercise Therapy in Patients with Intermittent Claudication

The Vascular Quality of Life Questionnaire-6 (VascuQoL-6) is a short, disease specific instrument used to determine health related quality of life (HRQoL) in patients with peripheral arterial disease. This study aimed to assess the minimally important difference (MID) and substantial clinical benefit (SCB) of the VascuQoL-6 in Dutch patients with intermittent claudication (IC) receiving supervised exercise therapy (SET). Consecutive patients with IC who were recruited from a single centre between January 2016 and December 2016 completed the VascuQoL-6 before initiation and after three months of SET. They subsequently answered an anchor question rating their current health status as much improved, improved, unchanged, deteriorated, or much deteriorated, compared with baseline. The MID for improvement and deterioration and SCB were calculated using anchor based and distribution based methods. A total of 124 patients with IC (58% male, mean age 68 years) completed the study protocol. Baseline VascuQoL-6 scores increased from 16.3 ± 4.4 to 18.7 ± 3.8 after three months of SET (p < .001). MID values ranged from+2.0 to+3.8 points regarding HRQoL improvement and from+0.2 to -2.2 points regarding HRQoL deterioration. The SCB ranged from+3.7 to+5.0 points. Depending on the MID approach, 32% - 41% of patients achieved a clinically meaningful improvement in HRQoL. Approximately one in three patients with IC reported a clinically meaningful improvement in HRQoL after three months of SET. The range of MID and SCB values provides caregivers with an idea of how much change in VascuQoL-6 scores is considered relevant or substantial by their patients. Applying cutoff points for MID and SCB may optimise the interpretation of trial results and may help to set a benchmark for success of SET.

Testing the Responsiveness of and Defining Minimal Important Difference (MID) Values for the CARe Burn Scales: Patient-Reported Outcome Measures to Assess Quality of Life for Children and Young People Affected by Burn Injuries, and Their Parents/Caregivers

The CARe Burn Scales are a portfolio of burn-specific PROMs for people affected by burns, including a Child Form (for children &lt; 8 years (parent-proxy)), a Young Person Form (for young people aged 8–17 years), an Adult Form, and a Parent Form (for parents/carers of children aged 0–17 years). This study aimed to determine the responsiveness and minimal important difference (MID) values of the three scales developed for use in paediatric burn services and research. Participants were recruited by 15 UK Burn Services. Participants completed the appropriate CARe Burn Scale and a set of appropriate comparison validated measures, at three time points: 4 weeks (T1), 3 months (T2) and 6 months (T3) post-burn injury. Spearman’s correlation analysis and effect sizes based on Cohen’s d thresholds were reported and MID values were calculated. At baseline, 250 participants completed the Child Form, 69 completed the Young Person Form, and 320 completed the Parent Form. A total of 85–92% of participants were retained at follow up. The tested CARe Burn Scales were all responsive to change over time. MID values were created for all subscales and ranged from 2 to 11 for the Child Form, 3 to 14 for the Young Person Form and 3 to 10 for the Parent Form. The CARe Burn Scales for children, young people and parents are responsive to change over time. The scales are freely available for clinical and research use.

Methodological approach for determining the Minimal Important Difference and Minimal Important Change scores for the European Organisation for Research and Treatment of Cancer Head and Neck Cancer Module (EORTC QLQ-HN43) exemplified by the Swallowing scale

PurposeThe aim of this study was to explore what methods should be used to determine the minimal important difference (MID) and minimal important change (MIC) in scores for the European Organisation for Research and Treatment of Cancer Head and Neck Cancer Module, the EORTC QLQ-HN43.MethodsIn an international multi-centre study, patients with head and neck cancer completed the EORTC QLQ-HN43 before the onset of treatment (t1), three months after baseline (t2), and six months after baseline (t3). The methods explored for determining the MID were: (1) group comparisons based on performance status; (2) 0.5 and 0.3 standard deviation and standard error of the mean. The methods examined for the MIC were patients' subjective change ratings and receiver-operating characteristics (ROC) curves, predictive modelling, standard deviation, and standard error of the mean. The EORTC QLQ-HN43 Swallowing scale was used to investigate these methods.ResultsFrom 28 hospitals in 18 countries, 503 patients participated. Correlations with the performance status were |r|< 0.4 in 17 out of 19 scales; hence, performance status was regarded as an unsuitable anchor. The ROC approach yielded an implausible MIC and was also discarded. The remaining approaches worked well and delivered MID values ranging from 10 to 14; the MIC for deterioration ranged from 8 to 16 and the MIC for improvement from − 3 to − 14.ConclusionsFor determining MIDs of the remaining scales of the EORTC QLQ-HN43, we will omit comparisons of groups based on the Karnofsky Performance Score. Other external anchors are needed instead. Distribution-based methods worked well and will be applied as a starting strategy for analyses. For the calculation of MICs, subjective change ratings, predictive modelling, and standard-deviation based approaches are suitable methods whereas ROC analyses seem to be inappropriate.

Sensitivity to Change and Responsiveness of the Original and the Shortened Version of the Community Balance and Mobility Scale for Young Seniors

ObjectiveTo examine sensitivity to change and responsiveness of the Community Balance and Mobility Scale (CBM) and shortened CBM (s-CBM). DesignSecondary analysis using data of a randomized controlled trial. SettingGeneral community. ParticipantsYoung community-dwelling seniors aged 61-70 years (N=134; mean age, 66.2±2.5y). InterventionsParticipants underwent 12 months of exercise intervention. Main Outcome MeasuresCBM and s-CBM. Sensitivity to change was assessed using standardized response mean (SRM) and paired t tests as appropriate. Responsiveness was assessed using 2 minimal important difference (MID) estimates. Analyses were conducted for the full sample and for the subgroups “high-balance” and “low-balance,” divided by median split. ResultsInferential statistics revealed a significant CBM (P<.001) and s-CBM (P<.001) improvement within the full sample and the subgroups (high-balance: P=.001, P=.019; low-balance: P<.001, P<.001). CBM and s-CBM were moderately sensitive to change (SRM, 0.48 vs 0.38) within the full sample. In the high-balance subgroup, moderate SRM values (0.70) were found for the CBM and small values for the s-CBM (0.29). In the low-balance subgroup, moderate SRM values were found for the CBM (0.67) and high values for the s-CBM (0.80). For the full sample, CBM and s-CBM exceeded the lower but not the higher MID value. In the high-balance subgroup, the CBM exceeded both MID values, but the s-CBM exceeded only the lower. In the low-balance subgroup, CBM and s-CBM exceeded both MID values. ConclusionsThe CBM is a suitable tool to detect intervention-related changes of balance and mobility in young, high-performing seniors. Both versions of the CBM scale show good sensitivity to change and responsiveness, particularly in young seniors with low balance.

Commentary: Online Platform of Minimal Important Difference estimates for patient reported outcomes: potential and challenges

Carrasco-Labra et al. [ [1] Carrasco-Labra A, Devji T, Qasim A, Phillips MR, Wang Y, Johnston BC, et al. Minimal important difference estimates for patient-reported outcomes: a systematic survey. J Clin Epidemiol (in press). Google Scholar ] are to be congratulated for opening the door to more useful and useable information resulting from reviews of outcome measurement instruments. Rather than existing in the files of the authors, and reported in an article, they have moved the findings from a thorough review of the literature onto an online, searchable database of 5,324 minimally important difference (MID) values extracted for 526 instruments from 585 studies. At a minimum, they have just saved researchers, clinicians and policy makers needing estimates of MIDs countless hours of work finding these often elusive values within the literature and leaving the work of finding that data to people skilled in systematic reviews of available evidence. MID values are challenging to find. A less than thorough search may identify only some of the studies, or mistakenly lead people to settle on the first value found. However, MIDs play an important role in clinical trial planning, so all potentially relevant evidence should be brought to bear on the final decision. Sharing this information on an online platform will make clinical research more efficient to do, and more interpretable in policymaking and clinical care. This idea of developing interactive repositories of measurement study results with key data extracted from each study to enable its use is valuable in and of itself. But this article also provides the high-level results of this review.

Effect of Patient Demographics on Minimally Important Difference of Ankle Osteoarthritis Scale Among End-Stage Ankle Arthritis Patients.

Background:Ankle replacement and ankle arthrodesis are standard treatments for treating end-stage ankle arthritis when conservative treatment fails. Comparing patient-reported outcome scores to the instrument’s minimal important difference (MID) helps physicians and researchers infer whether a meaningful change in health from the patient’s perspective has occurred following treatment. The objective of this study was to estimate the MID of the Ankle Osteoarthritis Scale among a cohort of operatively treated end-stage ankle arthritis patients undergoing ankle replacement or arthrodesis.Methods:A survey package including the Ankle Osteoarthritis Scale was completed by participants preoperatively and 2 years postoperatively. Distribution and anchor-based approaches to calculating the MID were used to estimate the MID of the Ankle Osteoarthritis Scale and its 2 domains. The distribution-based approaches used were the small and medium effect size methods, while the mean absolute change method and linear regression method were the anchor-based approaches. Bootstrap sampling was used to obtain the variance of MID estimates. The MID was estimated for sex, age, operative, and baseline health subgroups. The cohort comprised 283 participants, totaling 298 ankles.Results:The MID did not vary with sex or operative procedure. Age-based differences in MID values may exist for the Ankle Osteoarthritis Scale total score, and MID values were generally smallest among the oldest patients. Patients with the best and worst ankle-related health preoperatively had higher MID values than patients reporting mid-range Ankle Osteoarthritis Scale values preoperatively.Conclusion:The best estimate of the MID of the Ankle Osteoarthritis Scale total score is 5.81. Our findings indicate that the MID of the Ankle Osteoarthritis Scale may not vary by sex or operative subgroups but likely varies by age and preoperative Ankle Osteoarthritis Scale score.Level of Evidence:Level II, prospective comparative study.

Hyperhidrosis Quality of Life Index (HidroQoL©): further validation and clinical application in patients with axillary hyperhidrosis using data from a phase III randomized controlled trial.

The Hyperhidrosis Quality of Life Index (HidroQoL©) is a validated patient-reported outcome measure capturing the quality of life of people affected by hyperhidrosis. We aimed to extend the validity evidence to physician-confirmed diagnosis of primary axillary hyperhidrosis. Data from a phase III randomized placebo-controlled clinical trial were used (n = 171). Confirmatory factor analysis was carried out to confirm the a priori two-factor structure of the HidroQoL. Internal consistency was assessed using Cronbach's α. Intraclass correlation coefficients (ICCs) were calculated to evaluate test-retest reliability after days -7 to -4. Convergent validity was assessed using correlations with the Dermatology Life Quality Index (DLQI), the Hyperhidrosis Disease Severity Scale (HDSS) and gravimetric sweat production. Known groups were analysed to evaluate discriminative validity. Responsiveness after 29 days was assessed and minimal important difference (MID) values were calculated using both anchor- and distribution-based approaches. All analyses were carried out for total HidroQoL and its two domains. The two-factor structure of the HidroQoL was confirmed. Internal consistency and test-retest reliability were strong (Cronbach's α 0·81-0·90; ICCs 0·89-0·93). Correlations with other outcome measures were in line with a priori hypotheses. The HidroQoL discriminated between different severity groups (P ≤ 0·001) and showed sensitivity to change towards improvement (P < 0·001). An MID value of 4 is proposed for the total scale. This study supports excellent measurement properties including clinical applicability of the HidroQoL in primary axillary hyperhidrosis and suggests a MID of 4 be applied to clinical trial data.

Minimally important differences for interpreting European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 scores in patients with head and neck cancer.

We aimed to estimate minimally important difference (MID) for interpreting group-level change over time for European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire core 30 (EORTC QLQ-C30) scores in head and neck cancer. Data were derived retrospectively from two published EORTC trials. Clinical anchors were selected using correlation strength and clinical plausibility of the given anchor/QLQ-C30 scale pair. MIDs for within-group and between-group change were estimated via the mean change method and linear regression, respectively. Distribution-based MIDs were also examined. MIDs for two of the scales, dyspnea and nausea/vomiting, are more uncertain considering their low correlations with the anchors. Anchor-based MIDs could be determined for deterioration in 7 of the 14 QLQ-C30 scales assessed, and in 3 scales for improvement. MIDs varied by scale, direction of change, and anchor. Absolute MID values ranged from 5 to 15 points for within-group change and 4 to 12 for between-group change. Most MIDs were within 4 to 10 points. Our findings, if confirmed, will aid interpreting changes in selected QLQ-C30 scale scores over time and inform sample size calculations in future clinical trials in head and neck cancer.

The running shoe comfort assessment tool (RUN-CAT): Development and evaluation of a new multi-item assessment tool for evaluating the comfort of running footwear

ABSTRACT Comfort is important for running shoe prescription in athletes to enhance performance and potentially decrease injury risk. A three-stage process was used to develop a new running footwear comfort assessment tool (RUN-CAT): (i) a survey of 282 runners to identify meaningful items of comfort, (ii-a) field testing of 100 runners who assessed the comfort of different shoes, (ii-b) item reduction using bootstrap aggregation and weightings using multiple regressions to identify a final set of items, and (iii) defining test-retest reliability, standard error of measurement (SEM), minimal detectable difference (MDD90) and minimal important difference (MID) values for the final tool. Of the 19 initial items, after item reduction, four were included in the final tool: heel cushioning, shoe stability, forefoot cushioning and forefoot flexibility. Reliability of the overall comfort score was good to excellent (within-day ICC 0.88, between-day 0.70) with all four components displaying good reliability (ICC >0.70). The SEM of the comfort score was 2.8 points and the MDD90 was 6.5 mm. Subject nominated MID values ranged from 9.3 to 9.9 mm. The RUN-CAT demonstrates excellent reliability, acceptable measurement error and can discriminate between footwear models. Clinicians and researchers can incorporate the RUN-CAT to optimise running shoe comfort in athletes.

Determination of the minimally important difference in a nasal symptom score in house dust mite allergy

House dust mite (HDM) allergens are responsible for the most prevalent persistent respiratory allergies. Clinical trials in this field often use a four-component nasal symptom score (T4NSS) as a measure of efficacy. The present observational, prospective, multinational, multicenter study determined the minimal important difference (MID) for a T4NSS in children, adolescents, and adults with physician-diagnosed HDM-induced allergic rhinoconjunctivitis (AR). Patients rated the T4NSS daily, a 15-point global rating of change scale (GRCS)and the Rhinoconjunctivitis Quality of Life Questionnaire weekly. The MID was determined primarily by using a regression method with a GRCS threshold of 2. A total of 546 patients (210 adults, 133 adolescents, and 203 children) were included; 92.6% of the patients had moderate-to-severe AR, and 30.1% had concomitant mild asthma. During the first week, the mean±standard deviation T4NSS was 5.68±2.76 in adults, 5.34±2.66 in adolescents, and 5.07±2.48 in children. In a GRCS regression analysis, the MID [95% confidence interval] for the T4NSS was -0.90 [-1.06;-0.75] overall (n=509), -0.94 [-1.19;-0.69] in children (n=187), -0.74 [-1.07;-0.41] in adolescents (n=125), and -1.04 [-1.29;-0.79] in adults (n=197). The MID did not differ greatly from one disease severity tertile to another. Confirmatory distribution-based analyses yielded overall MID values of -0.87 for the first week of the study and -0.93 for the week 2-week 1 difference. The MID for improvement in the T4NSS is at least -0.90 units in children, adolescents, and adults suffering from HDM-induced AR This value could be rounded up to -1 unit for convenience.

Clinical efficacy of bronchodilators in equine asthma: Looking for minimal important difference.

Airway obstruction is the main trait of severe equine asthma that affects respiratory function and elicits detrimental effects on clinical presentation. Only few and underpowered clinical studies have investigated the impact of improvement in lung function induced by bronchodilators on the clinical signs of asthma-affected horses. To identify the minimal important difference (MID) in lung function elicited by bronchodilator leading to a meaningful improvement in clinical signs. Pairwise meta-analysis and meta-regression analysis. Literature searches were performed for studies that investigated the effect of bronchodilator therapy on lung function and clinical condition of asthmatic horses. The relationship between the change in lung function variables and clinical score was analysed via random-effect meta-regression. One-point change of the Improved clinically Detectable Equine Asthma Scoring System (IDEASS) score was used to identify the MID. A significant (P<0.05) relationship was found between the changes in IDEASS score and maximum change in transpulmonary pressure (ΔPplmax ) or pulmonary resistance (RL ). Since only the model resulting for RL passed through the origin (Y-intercept when X=0: -0.31, 95% CI -0.75 to 0.14), this variable was used to identify the MID correlated with a meaningful improvement in clinical signs. The resulting MID value was a change in RL of 0.63cmH2 O/L/s (95% CI 0.33-0.94), representing the slope of meta-regression model (high quality of evidence). No long-term studies investigated the effect of bronchodilator agents on both lung function and clinical signs in asthmatic horses. In conclusion, bronchodilator pharmacotherapy in equine asthma elicits clinically meaningful effect when RL increases ≥1cmH2 O/L/s, a value indicating the MID. Assessing the MID based on change in RL may improve the quality of evidence and the scientific impact of future clinical trials as it extends beyond the simple, and limiting, evaluation of statistical significance.

The cross-cultural validation of the English version of RhinAsthma patient’s perspective (RAPP)

Objective: No validated instrument is currently available in English for use in daily practice to assess Health Related Quality of Life (HRQoL) in asthma and comorbid allergic rhinitis (AR). The aim of this study was to validate and assess the psychometric characteristics of an English language version of RhinAsthma Patient Perspective (RAPP).Methods: The study was performed in the Philippines. The RAPP was translated into English. Adult patients, diagnosed with asthma and AR, were recruited. Clinical and functional data were collected on two occasion with a 4-week interval between visits. At both visits patients completed the following questionnaires: RAPP, Short Form Heath Survey-12 (SF-12), asthma control test (ACT), and rhinitis symptom Visual Analog Scale (VAS). Scale dimensions, internal consistency and convergent validity, reliability, discriminant ability, responsiveness, and minimal important difference (MID) were evaluated.Results: About 150 patients (mean age 39.3 years) completed the study. Exploratory and confirmatory factor analysis identified a uni-dimensional structure of the questionnaire. Internal consistency was satisfactory (0.87 at visit 1; 0.89 at visit 2). The tool showed good discriminant and convergent validity at both visits (p < 0.01). High reliability was confirmed by an ICC of 0.97 and a CCC of 0.95. Responsiveness was shown by a significant association with VAS (r = 0.34, p < 0.01) and ACT (r = −0.35, p < 0.01). The MID value was 2.Conclusions: The English version of RAPP was shown to have good psychometric properties and is a valid tool for assessing asthma and AR HRQoL in clinical practice.