Minimal Important Difference Values Research Articles

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.

Long-term biological variation of high-sensitivity cardiac troponin T using minimal important differences and reference change values in stable outpatients with cardiovascular disease

ObjectiveTo evaluate the long term biological variation of high-sensitivity cardiac troponin T (hs-cTnT) in stable outpatients with cardiovascular disease (CVD). MethodsAfter applying 8 exclusion criteria to 965 patients, hs-cTnT was measured at index visit and at a 12-month interval in 169 stable outpatients presenting for routine follow-up visits for any CVD. Stability was defined as absence of any endpoint within the follow-up period. Reference change values (RCVs) and minimal important differences (MIDs) were determined to assess biological variation of hs-cTnT. ResultsMID and RCV for the 12 months interval in patients were 3.8 ng/L or 44.2%, respectively. MID and transformed MID values were lower than the corresponding RCV with a value of 5.1 ng/L for the transformed RCV and 28.1% for the transformed MID. Similar patterns were shown in different subgroups as sex, age, and renal function. We observed a baseline hs-cTnT value dependent change of MID and RCV with increasing values for MID and decreasing values for RCV which converge to stable values between a baseline hs-cTNT value of 11 to 25 ng/L. ConclusionsBiological variation of hs-cTnT over 12 months in stable outpatients depends on the concentration at index visit, and is consistent among important prespecified subgroups. MID shows a low biovariability over 12 months.Clinical Trials Identifier:NCT01954303

Brief communication: use of the minimal important difference for a meta-analysis on exercise and anxiety in adults with arthritis.

A recent meta-analysis reported statistically significant improvements in anxiety as a result of exercise in adults with arthritis and other rheumatic diseases (AORD) using the traditional standardized mean difference (SMD) effect size (ES). The objective of this study was to use the more recently developed and clinically relevant minimal important difference (MID) approach to examine this association. Data from a previous meta-analysis of 14 randomized controlled trials representing 926 initially enrolled adults ≥ 18years of age (539 exercise, 387 control) was used to calculate the ES using the MID approach. Minimal important difference data were derived from previously reported anchor-based values that represented the different instruments used to assess anxiety. Effect sizes were pooled using the inverse heterogeneity (IVhet) model. Overall, exercise resulted in a mean ES reduction in anxiety of - 0.80 (95% CI, - 1.60 to 0.001, p = 0.05; Q = 92.1, p < 0.001, I 2 = 83.7%, 95% CI, 74.9%, 89.5%), suggesting that overall, exercise may benefit an appreciable number of patients. Nonetheless, this effect spanned the range from many patients gaining important benefits to no patients improving. The clinically relevant effects of exercise on anxiety in adults with AORD are varied. However, these results should be interpreted with caution given the absence of anchor-based MID data specific to the instruments and questions used to assess anxiety in adults with AORD. A need exists for future research to establish instrument-specific, anchor-based MID values for questions assessing anxiety in adults with AORD.

Assessing the Impact of Growth Hormone Deficiency (GHD) in Adults: Interpreting Change of the Treatment-Related Impact Measure-Adult Growth Hormone Deficiency (TRIM-AGHD).

BackgroundThis study’s purpose was to assess the minimal important difference (MID) for the Treatment-Related Impact Measure—Adult Growth Hormone Deficiency (TRIM–AGHD), a patient-reported outcome measure assessing growth hormone deficiency (GHD) impacts. The measure was demonstrated to have adequate psychometric measurement properties, and be reliable and valid. For scores to be interpretable, the TRIM-AGHD must be responsive to treatment benefit and the MID in scores quantified.MethodsA prospective, non-interventional, observational, clinic-based survey study of naïve-to-treatment adult GHD patients (N = 98) was conducted. Key assessments were at baseline and follow-up (between 4 and approximately 8 weeks), with weekly telephone monitoring post-baseline (last n = 34 patients). Responsiveness was evaluated using the effect size of change scores from baseline to follow-up. MID estimates were derived from distribution-based (half standard deviation [0.5 SD], standard error of measurement [SEm]) and anchor-based methods (patient global rating of change [PGRC]) using change scores from baseline to initial report of minimal improvement in GHD severity. Findings from each method were converged to establish an acceptable MID.ResultsPatients were mean age 49.7 years, 65.6% female, and 76.0% Caucasian. The TRIM-AGHD was highly responsive to treatment with the total score effect size being 1.38. For the total score, the 0.5 SD was 8.09 and the SEm was 2.66. The difference found using the PGRC was 20.43. The converged MID value for the total score was 10 points.ConclusionsThe TRIM-AGHD is a highly responsive measure assessing AGHD treatment impacts. A 10-point change score is considered a clinically meaningful improvement.

The German version of the Expanded Prostate Cancer Index Composite (EPIC): translation, validation and minimal important difference estimation

BackgroundNo official German translation exists for the 50-item Expanded Prostate Cancer Index Composite (EPIC), and no minimal important difference (MID) has been established yet. The aim of the study was to translate and validate a German version of the EPIC with cultural adaptation to the different German speaking countries and to establish the MID.MethodsWe translated and culturally adapted the EPIC into German. For validation, we included a consecutive subsample of 92 patients with localized prostate cancer undergoing radical prostatectomy who participated the Prostate Cancer Outcomes Cohort. Baseline and follow-up assessments took place before and six weeks after prostatectomy in 2010 and 2011.We assessed the EPIC, EORTC QLQ-PR25, Feeling Thermometer, SF-36 and a global rating of health state change variable. We calculated the internal consistency, test-retest reliability, construct validity, responsiveness and MID.ResultsFor most EPIC domains and subscales, our a priori defined criteria for reliability were fulfilled (construct reliability: Cronbach’s alpha 0.7–0.9; test-retest reliability: intraclass-correlation coefficient ≥ 0.7). Cross-sectional and longitudinal correlations between EPIC and EORTC QLQ-PR25 domains ranged from 0.14–0.79, and 0.06–0.5 and 0.08–0.72 for Feeling Thermometer and SF-36, respectively. We established MID values of 10, 4, 12, and 6 for the urinary, bowel, sexual and hormonal domain.ConclusionThe German version of the EPIC is reliable, responsive and valid to measure HRQL in prostate cancer patients and is now available in German language. With the suggested MID we provide interpretation to what extent changes in HRQL are clinically relevant for patients. Hence, study results are of interest beyond German speaking countries.

Sensitivity and responsiveness to change for the Brazilian version of the child perceptions questionnaire for 8- to 10-year-old children

This study aimed to investigate the sensitivity and responsiveness to change for the Brazilian version of the Child Perceptions Questionnaire (CPQ8–10) after dental caries treatment. Thirty children aged 8 to 10 years old with untreated dental caries were randomly selected from public schools. They responded to the CPQ8–10 before and 1 month after finishing treatment for dental caries. Sensitivity was assessed by determining distribution changes using paired t-tests and Wilcoxon signed-rank tests. Responsiveness to change was evaluated by effect size (ES) and standardized response mean (SRM). Minimally important differences (MIDs) were also evaluated. Mean/median pre-treatment values for the total CPQ8–10 score and subscales were significantly higher than the post-treatment values (p < 0.05). ES was large (effect size ≥ 0.8) for the total CPQ8–10 score and oral symptoms (OS), functional limitations (FL) and emotional wellbeing (EW) subscales and moderate (effect size 0.3–0.7) for the social wellbeing (SW) subscale. SRM values were moderate (0.3–0.7) for the total CPQ8–10 score and FL, EW and SW subscales and high (≥ 0.8) for the OS subscale. MID values for the total CPQ8–10 score and all subscales were lower than the mean score change. The Brazilian version of the CPQ8–10 is sensitive and responsive enough to detect changes brought about by dental caries treatment.

Responsiveness of postural performance measures following balance rehabilitation in multiple sclerosis patients

IntroductionEvaluating responsiveness has an important role in design and interpretation of the interventional studies. The aim was to estimate the responsiveness and minimally important difference (MID) of postural performance measures following balance rehabilitation in patients with Multiple Sclerosis (MS, n = 38). MethodsPostural measures were evaluated at baseline and after 4 weeks intervention. Laboratory-based measures were center of pressure parameters. Clinically-based measures were Activities-specific Balance Confidence (ABC), Berg Balance Scale (BBS), Functional Gait Assessment (FGA); and walking measures 2 Minute Walk (2 MW), 10 Meter Timed Walk (10 MTW) and Timed Up and Go (TUG) performed under single and dual-task conditions. To evaluate responsiveness, we calculated the Receiver Operating Characteristics (ROC) and the Area Under the ROC Curve (AUC). The optimal values for the MID were the cutoffs corresponding to the upper left corner of the ROC curve. ResultsThe AUCs for mean and standard deviation of sway velocity were above the cutoff of 0.50 in most conditions. For the clinically-based measures, the highest AUCs were found for the ABC, and cognitive-2MW, followed by the BBS and 10 MTW. ConclusionsIn this preliminary study, the most appropriate postural performance measures and the MID values for detecting meaningful changes in MS undergoing balance rehabilitation have been provided.

Application of minimal important differences in degenerative knee disease outcomes: a systematic review and case study to inform BMJ Rapid Recommendations

ObjectivesTo identify the most credible anchor-based minimal important differences (MIDs) for patient important outcomes in patients with degenerative knee disease, and to inform BMJ Rapid Recommendations for arthroscopic surgery versus...

Asthma Control and Sputum Eosinophils: A Longitudinal Study in Daily Practice

Longitudinal trials have suggested that asthma control may be influenced by fluctuations in eosinophilic inflammation. This association has however never been confirmed in daily practice. To investigate the relationship between asthma control and sputum eosinophils in clinical practice. A retrospective longitudinal study was conducted on 187 patients with asthma with at least 2 successful sputum inductions at our Asthma Clinic. Linear mixed models were used to assess the relationship between asthma control and individual changes in sputum eosinophils. Receiver-operating characteristic curves were constructed to define minimal important differences (MIDs) of sputum eosinophils associated with a change of at least 0.5 in Asthma Control Questionnaire (ACQ) score. Then, a validation cohort of 79 patients with asthma was recruited to reassess this relationship and the accuracy of the MID values. A multivariate analysis showed that asthma controlwasindependently associated with individual fluctuationsin sputum eosinophil count (P < .001). In patients with intermittent/persistently eosinophilic asthma, we calculated a minimal important decrease of 4.3% in the percentage of sputum eosinophils (area under the curve [AUC], 0.69; P < .001) or 3.4-fold (AUC, 0.65; P= .003) for a significant improvement in asthma control and a minimal important increase of 3.5% (AUC, 0.67; P=.004) or 1.8-fold (AUC, 0.63; P= .02) for a significant worsening in asthma control. The association between asthma control and sputum eosinophils and the accuracy of the MIDs of sputum eosinophils were confirmed in the validation cohort. At the individual level, asthma control was associated with fluctuations in sputum eosinophil count over time.

Patient-reported questionnaires in MS rehabilitation: responsiveness and minimal important difference of the multiple sclerosis questionnaire for physiotherapists (MSQPT)

BackgroundThe Multiple Sclerosis Questionnaire for Physical Therapists (MSQPT) is a patient-rated outcome questionnaire for evaluating the rehabilitation of persons with multiple sclerosis (MS). Responsiveness was evaluated, and minimal important difference (MID) estimates were calculated to provide thresholds for clinical change for four items, three sections and the total score of the MSQPT.MethodsThis multicentre study used a combined distribution- and anchor-based approach with multiple anchors and multiple rating of change questions. Responsiveness was evaluated using effect size, standardized response mean (SRM), modified SRM and relative efficiency. For distribution-based MID estimates, 0.2 and 0.33 standard deviations (SD), standard error of measurement (SEM) and minimal detectable change were used. Triangulation of anchor- and distribution-based MID estimates provided a range of MID values for each of the four items, the three sections and the total score of the MSQPT. The MID values were tested for their sensitivity and specificity for amelioration and deterioration for each of the four items, the three sections and the total score of the MSQPT. The MID values of each item and section and of the total score with the best sensitivity and specificity were selected as thresholds for clinical change.The outcome measures were the MSQPT, Hamburg Quality of Life Questionnaire for Multiple Sclerosis (HAQUAMS), rating of change questionnaires, Expanded Disability Status Scale, 6-metre timed walking test, Berg Balance Scale and 6-minute walking test.ResultsThe effect size ranged from 0.46 to 1.49. The SRM data showed comparable results. The modified SRM ranged from 0.00 to 0.60. Anchor-based MID estimates were very low and were comparable with SD- and SEM-based estimates. The MSQPT was more responsive than the HAQUAMS in detecting improvement but less responsive in finding deterioration. The best MID estimates of the items, sections and total score, expressed in percentage of their maximum score, were between 5.4% (activity) and 22% (item 10) change for improvement and between 5.7% (total score) and 22% (item 10) change for deterioration.ConclusionsThe MSQPT is a responsive questionnaire with an adequate MID that may be used as threshold for change during rehabilitation of MS patients.Trial registrationThis trial was retrospectively (01/24/2015) registered in ClinicalTrials.gov as NCT02346279.

Quality of Life in the Tube Versus Trabeculectomy Study

To report the vision-specific quality-of-life (QoL) outcomes in the Tube Versus Trabeculectomy (TVT) Study. Multicenter randomized clinical trial. Setting: Seventeen clinical centers. Patients 18-85 years of age with medically uncontrolled glaucoma who had previous cataract and/or glaucoma surgery. Tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with MMC. Vision-specific QoL using the NEI VFQ-25 and estimation of minimally important differences (MID) were the main outcome measures. Cross-sectional distribution- and anchor-based approaches were used to estimate MID. Clinical anchor measures included the mean deviation (MD) and logMAR visual acuity (VA) measurements. Clinically significant changes in anchor were defined as ≥2 dB MD and ≥0.2 logMAR. No significant differences in composite scores were observed between treatment groups, and no significant change in scores were seen over time. Mean (SD; range) values of clinical anchors at baseline were-16.6 (9.3;-32 to-0.5) dB for the surgical eye and 0.2 (0.3;-0.1 to 1.3) logMAR VA in the better-vision eye. For anchor-based cross-sectional analysis, composite score MID (95% CI) was 6.3 (4.6-7.9) for better-eye VA and 1.4 (0.9-1.9) for surgical eye MD. Distribution-based MID for the composite score was 6.0. Trabeculectomy and tube shunt surgery had similar impact on patient-reported vision-specific QoL measured using the NEI VFQ-25. In this cohort of patients with advanced glaucoma, MIDs varied depending on the clinical anchor used. Distribution-based MIDs corresponded well with anchor-based MIDs based on VA measures. The MID values reported here may be useful for others wishing to interpret NEI VFQ-25 scores in their advanced glaucoma patient cohort.

Minimally Important Differences and Change Across Time in Patients Treated Surgically and Non-Surgically for Full-Thickness Rotator Cuff Tears

Objectives:The minimally important difference (MID) is the smallest change in an outcome measure that is perceived by patients as beneficial. The MIDs for the ASES and WORC scores have not been established in a homogenous population of patients with rotator cuff tears. The objective of the present study was to establish the MIDs for patients with known cuff tears who were treated both surgically and non-surgically, and to compare the MIDs over time.Methods:We included 209 subjects with known full-thickness rotator cuff tears who were followed prospectively for two years. The WORC and ASES scores were collected at baseline, 4, 8, 16, 32, and 48 weeks, 1 year and 2 years. At the final follow-up point patients filled out an end-of-study form which included questions regarding change in their condition after treatment.Results:For those that indicated being minimally better, the change from baseline for the ASES score was -20.57 (-2.94 to -38.20) and for the WORC was 418.60 (70.39 to 766.81); both indicated improvement in outcomes. When converted to the percentage change score the WORC change represented 19.93%. The plots of these new MID values for the ASES and WORC indicate that not only does the operative group improve more than the non-operative group but it does so to an extent that is greater than the MID. The non-operative group also improved across time, but the magnitude did not exceed the MID for either the WORC or the ASES.Conclusion:We found that the ASES and the WORC MIDs in patients with rotator cuff tears is different from that previously reported, and that the operative group change was greater than the non-operative group change. This information will directly improve our ability to: (1) Determine when patients with RCTs are changing in a meaningful manner; (2) Accurately power clinical studies using these outcome measures; (3) Make more informed choices of treatments in these patients. This is the first study to report MIDs for the ASES and WORC in a population of patients with strictly rotator cuff disease and to explore their changes relative to MIDs across time.

Psychometric properties of the Neck OutcOme Score, Neck Disability Index, and Short Form–36 were evaluated in patients with neck pain

ObjectiveTo assess reliability, construct validity, responsiveness, and interpretability for Neck OutcOme Score (NOOS), Neck Disability Index (NDI), and Short Form–36 (SF-36) in neck pain patients. Study Design and SettingInternal consistency was assessed by Cronbach alpha. Test-retest reliability was evaluated by intraclass correlation coefficient (ICC), and measurement error was estimated from the standard error of measurement. Responsiveness was assessed as standardized response mean (SRM) and interpretability from the minimal important difference (MID). Construct validity was tested correlating subscale scores from NOOS and SF-36 and NDI items. ResultsAt baseline, 196 neck pain patients were included. Cronbach α was adequate for most NOOS subscales, NDI, and SF-36 with few exceptions. Good to excellent reliability was found for NOOS subscales (ICC 0.88–0.95), for NDI, and for SF-36 with few exceptions. For NOOS, minimal detectable changes varied between 1.1 and 1.9, and construct validity was supported. SRMs were higher for NOOS subscales (0.19–0.42), compared to SF-36 and NDI. MID values varied between 15.0 and 24.1 for NOOS subscales. ConclusionsIn conclusion, the NOOS is a reliable, valid, and responsive measure of self-reported disability in neck pain patients, performing at least as well or better than the commonly used SF-36 and NDI.

Determining the Minimally Important Difference for the VascuQol Sumscore and Its Domains in Patients with Intermittent Claudication

The VascuQol is a questionnaire for health related quality of life (HRQL) in patients with intermittent claudication (IC), and is frequently used to evaluate treatment effects. Yet, the interpretation of change in score on a questionnaire is not always obvious. The minimally important difference (MID) represents the smallest change in score on a questionnaire that is considered relevant by patients. This study aims to determine the MID for the VascuQol sumscore and its different domains for patients with IC. A total of 118 participants were recruited from the SUPER study, a multicenter randomized controlled trial comparing angioplasty with supervised exercise therapy for alleviation of IC due to an iliac artery stenosis or occlusion. All patients completed the VascuQol and the Short Form 36 (SF-36) questionnaires at baseline and after 12 months of follow up. Two anchor based methods for MID calculation were applied. Two anchors were used: six global rating of change questions aimed at the VascuQol sumscore and subscales and the health transition item of the SF-36, both recorded at 12 months of follow up. The MID for the VascuQol sumscore ranged between 1.19 and 1.66 for improvement and 0.08 and 0.41 for deterioration. For the pain domain, MID values ranged from 1.48 to 1.91 for improvement and 0.19 to 0.34 for deterioration. Finally, for the activities domain MID values ranging from 1.55 to 2.2 and from 0.12 to 0.26 for improvement and deterioration were found, respectively. Since the correlations between the anchors and the symptom, social and emotional subscales were below the threshold of 0.3, the MID was not calculated for these subscales. The range of MID values found in this study is an indication of the smallest change score on the VascuQol questionnaire score that is considered relevant by patients with IC. They may help to better interpret trial results and set treatment goals.

Interventions for fatigue in Parkinson's disease.

Factors contributing to subjective fatigue in people with idiopathic Parkinson's disease (PD) are not well known. This makes it difficult to manage fatigue effectively in PD. To evaluate the effects of pharmacological and non-pharmacological interventions, compared to an inactive control intervention, on subjective fatigue in people with PD. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); MEDLINE (via PubMed); Ovid EMBASE; EBSCO CINAHL; Ovid PsycINFO; PEDro; and the WHO International Clinical Trials Registry Platform Search Portal up to April 2015. References of included studies and identified review articles were screened for additional studies. There were no restrictions based on language, date of publication or study setting. Randomised controlled trials (RCTs) that report on subjective fatigue in people with PD. Two review authors independently performed study selection, data collection and risk of bias assessments. Eleven studies were eligible for this systematic review, with a total of 1817 people. Three studies included only people who experienced clinically relevant fatigue (Fatigue Severity Scale score ≥ 4 out of 7 or Multidimensional Fatigue Inventory total score > 48 out of 100), whereas all other studies did not select participants on the basis of experienced fatigue. Nine studies investigated the effects of medication (i.e. levodopa-carbidopa, memantine, rasagiline, caffeine, methylphenidate, modafinil or doxepin) on subjective fatigue. All studies were placebo controlled. There was insufficient evidence to determine the effect of doxepin on the impact of fatigue on activities in daily life (ADL) or fatigue severity (one study, N = 12, standardised mean difference (SMD) = -1.50, 95% confidence interval (CI) -2.84 to -0.15; low quality evidence). We found high quality evidence that rasagiline reduced or slowed down the progression of physical aspects of fatigue (one study, N = 1176, SMD = -0.27, 95% CI -0.39 to -0.16, I(2) = 0%). None of the other pharmacological interventions affected subjective fatigue in PD. With regard to adverse effects, only levodopa-carbidopa showed an increase for the risk of nausea (one study, N = 361, risk ratio (RR) = 1.85, 95% CI 1.05 to 3.27; high quality evidence). Two studies investigated the effect of exercise on fatigue compared with usual care. We found low quality evidence for the effect of exercise on reducing the impact of fatigue on ADL or fatigue severity (two studies, N = 57, SMD = -0.45, 95% CI -1.21 to 0.32, I(2) = 44%). Based on the current evidence, no clear recommendations for the treatment of subjective fatigue in PD can be provided. Doxepin may reduce the impact of fatigue on ADL and fatigue severity; however, this finding has to be confirmed in high quality studies. Rasagiline may be effective in reducing levels of physical fatigue in PD. No evidence was found for the effectiveness of levodopa-carbidopa, memantine, caffeine, methylphenidate, modafinil or exercise. Studies are needed to investigate the effect of exercise intensity on exercise capacity and subjective fatigue. Future studies should focus on interventions that address the maladaptive behavioural or cognitive aspects of fatigue in people with PD. Characteristics, such as severity and nature of perceived fatigue and underlying mood disorders should be considered to identify responders and non-responders when studying interventions for fatigue. The development of a core-set of self-report fatigue questionnaires with established responsiveness and known minimal important difference values will facilitate the interpretation of change in fatigue scores.

Introducing the Concept of the Minimally Important Difference to Determine a Clinically Relevant Change on Patient-Reported Outcome Measures in Patients with Intermittent Claudication.

PurposeThe minimally important difference (MID) represents the smallest change in score on patient-reported outcome measures that is relevant to patients. The aim of this study was to introduce the MID for the Vascular Quality of Life Questionnaire (VascuQol) and the walking impairment questionnaire (WIQ) for patients with intermittent claudication (IC).MethodsIn this multicenter study, we recruited 294 patients with IC between July and October 2012. Patients completed the VascuQol, with scores ranging from 1 to 7 (worst to best), and the WIQ, with scores ranging from 0 to 1 (worst to best) at first visit and after 4 months follow-up. In addition, patients answered an anchor-question rating their health status compared to baseline, as being improved, unchanged, or deteriorated. The MID for improvement and deterioration was calculated by an anchor-based approach, and determined with the upper and lower limits of the 95 % confidence interval of the mean change of the group who had not changed according to the anchor-question.ResultsFor the MID analyses of the VascuQol and WIQ, 163 and 134 patients were included, respectively. The MID values for the VascuQol (mean baseline score 4.25) were 0.87 for improvement and 0.23 for deterioration. For the WIQ (mean baseline score 0.39), we found MID values of 0.11 and −0.03 for improvement and deterioration, respectively.ConclusionIn this study, we calculated the MID for the VascuQol and the WIQ. Applying these MID facilitates better interpretation of treatment outcomes and can help to set treatment goals for individual care.Electronic supplementary materialThe online version of this article (doi:10.1007/s00270-015-1060-0) contains supplementary material, which is available to authorized users.

Interpretability of the PedsQL™ Gastrointestinal Symptoms Scales and Gastrointestinal Worry Scales in Pediatric Patients With Functional and Organic Gastrointestinal Diseases.

The present study investigates the clinical interpretability of the Pediatric Quality of Life Inventory™ (PedsQL™) Gastrointestinal Symptoms Scales and Worry Scales in pediatric patients with functional gastrointestinal disorders or organic gastrointestinal diseases in comparison with healthy controls. The PedsQL™ Gastrointestinal Scales were completed by 587 patients with gastrointestinal disorders/diseases and 685 parents, and 513 healthy children and 337 parents. Minimal important difference (MID) scores were derived from the standard error of measurement (SEM). Cut-points were derived based on one and two standard deviations (SDs) from the healthy reference means. The percentages of patients below the scales' cut-points were significantly greater than the healthy controls (most p values ≤ .001). Scale scores 2 SDs from the healthy reference means were within the range of scores for pediatric patients with a gastrointestinal disorder. MID values were generated using the SEM. The findings support the clinical interpretability of the new PedsQL™ Gastrointestinal Symptoms Scales and Worry Scales.

Responsiveness and minimally important differences for selected Persian-version of outcome measures used in patients with patellofemoral pain syndrome

Purpose: To investigate the responsiveness and determine the minimally important differences (MID) of Persian versions of the Kujala patellofemoral scale (KPS), lower extremity functional scale (LEFS), and functional index questionnaire (FIQ) in patients with patellofemoral pain syndrome (PFPS). Method: Outcome measures including the Persian KPS, LEFS, and FIQ were administered to 233 patients at baseline and then again 4 weeks after physiotherapy. Moreover, the 7-point global rating scale was completed by the patients at 4 weeks. Responsiveness was evaluated using the correlation analysis and the receiver operating characteristics (ROC) method. Results: Correlation analysis showed that the relationship of all outcome measures with the global rating scale falls within the fair range of relationship (Gamma = 0.26–0.40). Moreover, the results of ROC analysis showed that the all outcome measures have acceptable high responsiveness index. Furthermore, the MIDs of 9.5, 4.5, and 1.5 points were obtained for the Persian KPS, LEFS, and FIQ, respectively. Conclusions: The Persian-versions of all outcome measures are responsive for evaluating change following physiotherapy intervention. The MID values obtained in this study will help the clinicians and researchers to determine if a patient with PFPS has experienced a true change following a physiotherapy intervention.Implications for RehabilitationPersian-versions of the KPS, LEFS, and FIQ can be used as three “responsive” outcome measures in clinical studies of patients with patellofemoral pain syndrome (PFPS).These assessment tools have clinical relevance for rehabilitation specialists working on patients with PFPS.The minimally important differences provide valuable information for the clinicians and researchers to make decision about the identification of a clinical change in health status of patients with PFPS.