Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis

Transcription

1 Chapter 5 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis Arch Phys Med Rehabil 2008; 89: F.J. van der Giesen R.G.H.H. Nelissen J.H. Arendzen Z. de Jong R.Wolterbeek T.P.M Vliet Vlieland

2 Abstract Objective To investigate the responsiveness of the Michigan Hand Outcomes Questionnaire (MHQ) in patients with rheumatoid arthritis (RA) who were treated in a multidisciplinary hand clinic. Design Observational study comparing the responsiveness of the MHQ with that of various other outcome measures for hand function. Setting Multidisciplinary hand clinic within a tertiary referral center for rheumatologic care. Participants Twenty-eight patients with problems in hand function due to RA were assessed before and 3 months after conservative and/or surgical treatment. Main Outcome Measures Assessments included, apart from a previously validated Dutch language version of the MHQ, a visual analog scale for pain, grip strength, the Sequential Occupational Dexterity Assessment, the Arthritis Impact Measurement Scales (AIMS) hand and finger function scale, and the patient s rating of subjective change in hand function. Measurements of responsiveness included the standardized response mean (SRM), effect size, and responsiveness ratio. In addition, the Spearman rank correlations (ρ) between the change scores of the MHQ and those of other measures of hand function were calculated. Results The mean MHQ total score improved significantly between baseline (mean ± standard deviation, 48.3 ± 12.2) and followup (mean, 54.7 ± 16.9) (change score, -7.2; 95% confidence interval, to -3.3). The SRM, effect size, and responsiveness ratio of the MHQ total score, were -0.72, -0.52, and -1.99, respectively. Significant associations were found between the changes of the MHQ total score and each patient s rating of subjective change in hand function (ρ =.64, P =.001) and the change score of the AIMS hand function scale (ρ =-.24, P =.260). Conclusions The MHQ proved to be a responsive measure of hand function in patients with RA who were treated in connection with a multidisciplinary hand clinic. 76

3 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis Introduction Hand function problems are common in patients with rheumatoid arthritis (RA). It is estimated that the hands and wrists are affected in 80% to 90% of the patients with RA 1. The importance of hand function in RA is underlined by the fact that the fine hand use domain is included in the recently developed preliminary International Classification of Functioning, Disability and Health (ICF) 2 core set for RA 3. For the evaluation of hand function in patients with rheumatic diseases, a number of hand function performance tests and questionnaires are available. However, knowledge about the responsiveness of these outcome measures is scarce 4,5. An instrument that is frequently used in research on hand function is the Michigan Hand Outcomes Questionnaire (MHQ). The MHQ is a multidimensional instrument which was developed to measure outcomes in patients with different types of hand disorders 6. The MHQ distinguishes itself from other outcome measures because it incorporates, apart from more common dimensions such as activities of daily living and pain, the domains work and aesthetics, which are very relevant for patients with RA. Its reliability and validity in patients with RA have previously been established 7. Although its responsiveness has been demonstrated in various populations of patients with problems in hand function 8-12, its sensitivity to change has not yet been investigated specifically in patients with RA. The aim of this study was therefore to determine the responsiveness of the MHQ in RA patients with hand function problems who were treated in a multidisciplinary hand clinic. For this purpose a previously validated Dutch language version 13 of the MHQ was used. Methods Study Design and Patients This study was conducted at the day patient clinic of the Leiden University Medical Center. This clinic offers multidisciplinary team care for patients with rheumatic diseases 14, including 2 specific multidisciplinary programs: a vocational rehabilitation program 15 and a multidisciplinary hand clinic 16. The study involved consecutive patients who visited the multidisciplinary hand clinic for the first time between January 2002 and April 2004, underwent treatment following the advice of the multidisciplinary team, and were available for followup 3 months after treatment. The Medical Ethical Committee of the Leiden University Medical Center approved the study, and all patients gave written informed consent. The Multidisciplinary Hand Clinic The working methods of this clinic have been described in detail in a previously published observational study 16. In brief, the multidisciplinary hand clinic is aimed at patients with rheumatic diseases and a complex hand function problem, defined as a problem in hand function that cannot be solved by a single intervention and/or a single health professional. Referrals were performed by rheumatologists and orthopedic surgeons. The multidisciplinary team involved an orthopedic surgeon, a rehabilitation specialist, a rheumatologist, an occupational therapist, and a physical therapist. Patients visited the hospital twice for assessment and treatment advice. At the initial visit a standardized, comprehensive analysis of hand function problems was made by a physical therapist, who was the coordinator of the team; a rheumatologist; and an occupational therapist, in succession. At the second visit, with the entire multidisciplinary team and 77

4 patient present, a synopsis of the clinical assessments was presented by the coordinator. The orthopedic surgeon and rehabilitation specialist undertook additional history taking and physical examination, and subsequently a joint treatment plan was presented and discussed with the patient. Treatment could consist of conservative or surgical therapy or a combination of both. If an intervention was instituted, a followup appointment for a formal assessment after 3 months was scheduled. Assessment Methods All clinical assessments in connection with the hand function clinic were performed by 1 trained physical therapist (FJvdG), except for the Sequential Occupational Dexterity Assessment (SODA), which was performed by 5 trained occupational therapists. To enhance the interrater reliability among these occupational therapists, they all took part in a training session, and in addition calibration moments were scheduled every 3 to 4 months during the course of the study. Sociodemographic, disease, and treatment characteristics Sociodemographic data and disease characteristics included sex, age, and disease duration. In addition, the presence of ulnar deviation, boutonnière and swan neck deformities, and the possession of wrist splints were recorded. Moreover, data on the patients most important problems in hand function and types and numbers of interventions were listed. The MHQ The MHQ is a 57-item questionnaire, covering 6 domains: (1) overall hand function, (2) activities of daily living, (3) pain, (4) work performance, (5) aesthetics, and (6) patients satisfaction with hand function. The last 4 of these domains are scored for the right and left hand separately. The scoring method is described by the original authors of the MHQ 6. Each item is scored on a 1 to 5 scale, with the domain scores ranging from 0 to 100. If both hands are affected the left- and right-hand scale scores are averaged to get the score. For every domain, a higher score indicates a better hand function, except for the pain domain where a higher score means more pain. The total score (the average of all domains) ranges from 0 to 100, with a higher score indicating a better hand function. Hand and finger function scale of the Dutch Arthritis Impact Measurement Scales 2 The Dutch Arthritis Impact Measurement Scales 2 (D-AIMS2) is a questionnaire specifically designed to assess health status in subjects with RA 17. It consists of 12 domains, of which for this study only the hand and finger function domain was used. This domain consists of 5 questions, with the final score ranging from 0 to 10, with higher scores indicating worse hand function. Dexterity Dexterity was assessed by means of the SODA 18. With the SODA, patients performed 12 standardized tasks, 6 bimanual and 6 one-handed, representing all major grips such as pinch grip, cylindrical grip and writing grip. The assessor scored whether it was possible to perform the task in the standardized way, the effort that the activity took, and the pain the patients experienced when performing the task. The combination of the possibility to perform the tasks, and the effort and the pain score formed the SODA score, ranging from 0 to 108, with a higher number meaning a better hand function. The pain patients experienced when performing the tasks formed the SODA pain score, ranging from 0 to 78

5 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis 12, with a higher score indicating more pain. The SODA proved to be reliable, valid, and responsive to clinical changes in patients with RA Pain Hand pain during rest and in motion was measured by means of a 10-cm horizontal visual analog scale (VAS) for the left and right hand separately, with the left anchor representing no pain at all and the right anchor representing maximal pain. An average score over the left and right side was calculated in case of bimanual problems. Grip strength Grip strength was measured with a Jamar dynamometer 21,a. Before every measurement, it was checked whether the apparatus indicated a 0 score. Moreover, the device was not used for other purposes than the present study and all measurements were done in the same room with a centrally climate control, so that variation due to alterations in temperature or humidity could be ruled out. Patients sat on a chair with shoulders and wrist in neutral position and the elbow in 90 of flexion. They were asked to squeeze as hard as possible in the device and were vocally encouraged. In contrast with the recommendations of the American Society of Hand Therapy 22, we used 2 attempts instead of 3 attempts, because in patients with RA and problems with the hands and/or wrists, squeezing with maximal force is often very painful. Dependent on the previous experience with squeezing and the actual level of pain at the time of the test, the variability between the values of the first and second attempts is often considerable, with either the first or the second attempt yielding the highest score. For that reason, the highest score of 2 attempts was chosen as the final score. All 4 measurements were alternated between the right and left hand. The score was calculated separately for the left and right sides. An average score over the left and right side was calculated in case of bimanual problems. Subjective opinion about change in hand function At the followup assessment, patients were asked to rate the changes in hand function by means of a 5-point Likert scale (1, much worsened; 2, worsened; 3, not changed; 4, improved; 5, much improved). Statistical Analysis In a previous study in patients with rheumatic conditions, the mean MHQ total score ± standard deviation (SD) was 48.6 ± If it is assumed that the change score of the MHQ should exceed these 11.6 points, to measure an improvement in hand function, 25 patients would be sufficient to detect a significant difference, with α being.05 and a power (1 - β) of.90. For all clinical measures mean change scores were calculated (baseline minus followup) with the 95% confidence intervals (CIs). Responsiveness was evaluated by means of various methods 23,24 : the standardized response mean (SRM = pretreatment mean - post-treatment mean divided by the SD of the change score), the effect size (pretreatment mean - posttreatment mean divided by the SD of the pretreatment mean) 25, and Guyatt s responsiveness ratio (the mean change score of the improved patients divided by the SD of the baseline score in stable patients) 23. Patients were divided into improved, stable or deteriorated patients according to their subjective opinions of changes in hand function on a Likert scale. For this purpose, the scores were recoded as follows: 4 and 5, improved; 3, stable; and 1 and 2, deteriorated. A negative value of the SRM, effect size, or responsiveness 79

6 ratio indicates that the mean baseline score was smaller than the mean followup score. Values of.20,.50, and.80 or higher were considered to represent small, moderate, and large responsiveness for all 3 measures of responsiveness, respectively 24 ; however, for the responsiveness ratio a cutoff point of 1.96 for sufficient responsiveness has also been reported 26. All analyses were repeated for surgically and conservatively treated patients separately. In case of a combination of surgical and conservative treatment, patients were analyzed in the group of surgically treated patients. Differences between the changes of the MHQ total score in improved, stable, and deteriorated patients were tested by means of the unpaired Student t-tests. To establish whether changes in the MHQ reflected changes according to other outcome measures, Spearman correlations (ρ) between the change scores of the MHQ total score and other measures of hand function were calculated. Correlations (both negative and positive) from 0.10 to 0.29, 0.30 to 0.49, and 0.5 to 1.0 were considered small, medium and large, respectively 27. In addition, associations between the MHQ total score, MHQ subscale scores, and all other outcome measures on the one side and the patient s subjective opinion on the other side were calculated using Spearman correlations. Results In total, 28 RA patients (4 men, 24 women) with a median age of 54.0 years (range, 21-80y) years were included. The median disease duration was 17.3 years (range, y). Boutonnière deformities, swan neck deformities, or ulnar deviation were present in 15 (54%), 16 (57%), and 12 (43%) patients, respectively. Fifteen (54%) patients had wrist splints. The most important problems in hand function from the patients points of view were lack of grip (21 patients, 75%), pain (14 patients, 50%), and decreased grip strength (9 patients, 32%). Grip is defined as the ability to position the fingers and thumb around an object with the intention to pick up, grab or hold that object and grip strength is defined as the ability to apply force to an object while using a specific grip 16. Treatments comprised conservative treatment only (n=18), surgical treatment only (n=7), or a combination of both conservative and surgical treatment (n=3). Conservative treatment consisted of physical therapy (n=7), occupational therapy (n=15), or local or systemic medication (n=9) (single or combined modalities). Surgical treatment consisted of joint fusion (n=4), soft tissue correction (n=4), metacarpophalangeal joint replacement, carpal tunnel release, excision of tendon nodules, and excision of skin nodules (all n=1) (single or combined modalities). Table 1 shows that overall, patients improved between baseline and followup, except for VAS pain during activities and VAS pain while resting. The improvements reached statistical significance for the MHQ total score and 4 of its 6 subscales, for the SODA total score, and for the increase in grip strength. For the MHQ total score, the SRM (-.72) and the effect size (-.52) were moderate. The SRM of the subscales ranged from.15 for the pain subscale to -.89 for the aesthetics subscale. The effect size of the subscales ranged from.19 for the pain subscale to -.72 for the satisfaction subscale. Fourteen (50%) of the 28 patients stated that their most important hand function problem had improved (n=11) or much improved (n=3), 10 (36%) patients considered their problem unchanged (stable), whereas 4 (14%) patients stated their problem had worsened (n=3) or much worsened (n=1). The responsiveness ratio of the MHQ total score was -1.99, whereas the responsiveness ratio of the MHQ subscales varied between 0.64 for the pain subscale to for the satisfaction subscale. 80

7 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis Table 1. Baseline and followup scores of 28 patients with reumatoid arthritis treated in a multidisciplinary hand clinic Measures Baseline Followup Change (95% CI)* P SRM Effect Size Responsiveness Ratio MHQ total score (0-100) 48.3± ± (-11.1 to -3.3).001* Subscales (0-100) MHQ overall hand function 45.5± ± (-11.8 to 0.8) MHQ activities of daily living 55.4± ± (11.8 to 0.9).024* MHQ work 45.7± ± (19.9 to 1.1).030* MHQ pain 48.1± ± (-4.6 to 14.8) MHQ aesthetics 58.0± ± (17.5 to 6.7) <.001* MHQ satisfaction with hand function 36.1± ± (20.9 to 6.3).001* AIMS hand function (0-10) 4.6± ± (-0.2 to 1.1) SODA total score (0-108) 75.1± ± (11.7 to 0.3).039* SODA pain score (0-12) 3.0± ± (-0.09 to 1.7) VAS pain during activities (0-100) 29.8± ± (-11.2 to 8.4) VAS pain while resting (0-100) 15.0± ± (-6.5 to 3.7) Grip strength (Jamar, kg) 9.4 ± ± (4.8 to 0.4).022* NOTE. Values are mean ± standard deviation or as otherwise indicated. For all measures a negative change score (pretreatment mean posttreatment mean) means improvement, except for the MHQ pain score, the SODA pain score, the VAS for pain during activities and resting, and the AIMS hand function score, where a positive change score means improvement. * P-value of t-test. Significance set at P <.05. For the SRM and effect size, 0.2 is a small effect, 0.5 is a moderate effect, and 0.8 is a large effect. For the responsiveness ratio >1.96 is a clinically important effect

8 Of all other measures of hand function, the responsiveness of grip strength and the SODA total score were the greatest, but overall the values of the measures of responsiveness should be interpreted as small 26. Separate analyses of the 10 surgically and the 18 conservatively treated patients showed that the numbers of patients who considered themselves improved, stable or worse were 4, 4 and 2 patients in the surgically treated group and 10, 6, and 2 patients in the conservatively treated group, respectively. Both surgically and conservatively treated patients showed in concordance with the total group, overall improvement for all outcome measures, except for the VAS pain scores (results not shown). In the surgically treated group, there was in addition a slight deterioration with respect to the SODA pain score (-0.2; 95% CI, -2.4 to 2.0). In the surgically treated group, none of the changes reached statistical significance. In the conservatively treated group, similar to the results in the total group, significant improvements were seen with respect to the MHQ total score; the MHQ subscales activities of daily living, work, aesthetics, and satisfaction; and the SODA total score in the conservatively treated group. In contrast with the result of the total group, in the conservatively treated group the improvement of grip strength did not reach statistical significance; however, the improvement of the SODA pain score did (1.4; 95% CI 0.5 to 2.2). The measures of responsiveness in the surgically and conservatively treated groups were similar to those of the total group, with overall the MHQ total score showing the largest responsiveness compared with all other measures of hand function (results not shown). However, in the surgically treated group the SRM and effect size of grip strength (-.68, -.51, respectively) were higher than those of the MHQ total score (-.51, -.36, respectively), and the same was true for effect size of AIMS hand function (.37 for AIMS hand function, -.36 for MHQ total score). In the conservatively treated group, the SRM of the SODA pain score (.81) was higher than that of the MHQ total score (-.78). In line with the results of the total group, the MHQ subscales for satisfaction and aesthetics showed the highest responsiveness compared with the other subscales. In the total group of 28 patients, the mean change scores ± SD of the MHQ total score in the groups of patients who considered their main problem improved, stable or worsened were 11.3 ± 7.2, 1.3 ± 5.7, and -3.9 ± 10.9, respectively. Change scores between improved versus stable and improved versus worsened patients were significantly different (P =.008, P =.019, respectively), whereas the difference between stable and worsened patients did not reach statistical significance (P =.384). Table 2. Spearman s correlation between the change scores of the MHQ total score and the change scores of other measures of hand function in 28 patients with RA visiting a multidisciplinary hand clinic ρ P AIMS hand function * SODA total score SODA pain score VAS pain activities VAS pain rest Grip strength *P <.05 Table 2 shows the Spearman rank correlations between the change scores of the MHQ total score and the other measures of hand function. It was found that only the association 82

9 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis between the change score of the MHQ total score and the change score of the AIMS hand function scale reached statistical significance (ρ =-.52, P =.013). Table 3 shows the Spearman rank correlations between the patients opinions on change in hand function as measured on a Likert scale and the changes in the MHQ total score, MHQ subscales, and other measures of hand function. The change scores of the MHQ total score, and the MHQ the subscales of overall hand function, pain, and satisfaction were significantly associated with the patients opinion on changes in hand function. No other measures of hand function were significantly associated with the patients opinions on improvement. Table 3. Spearman s correlations between RA patients (N=28) opinions on change in hand function and change scores of various measures of hand function ρ P MHQ total score * MHQ Subscales Overall hand function * Activities of daily Work performance Pain * Aesthetics Satisfaction.78 <.001* AIMS hand function SODA total score SODA pain score VAS pain activities VAS pain rest Grip strength *P <.05 Discussion In this study evaluating the responsiveness of the MHQ in patients with RA receiving various treatments in connection with a multidisciplinary hand clinic, the responsiveness of the MHQ appeared to be moderate to good. Overall, its responsiveness was favorable compared with other common measures of hand function. Regarding the absolute values, the effect size and SRM of the MHQ total score were found to be moderate and concerning the MHQ subscales, the effect size and the SRM were small to moderate, according to published criteria 24, except for the aesthetics subscale which was found to have good responsiveness according to the SRM. The satisfaction with hand function subscale showed overall the greatest responsiveness, whereas the pain subscale, was the least responsive according to the statistical method. The responsiveness ratio of the MHQ total score and 3 of its subscales exceeded the criterion of 0.8 (good responsiveness) 24, with the MHQ total score and the satisfaction with hand function subscale both meeting the cutoff point of 1.96 or greater 26. Compared with the responsiveness of the other measures of hand function, the performance of the MHQ total score and its subscales was very favorable. 83

10 In general, associations between the change score of the MHQ total score and the change score of other measures of hand function were weak. These weak associations may indicate that the various measures all represent different aspects of changes in hand function. The associations between the change scores of the MHQ total score and its subscales and each patient s opinion on change of hand function were overall moderate, but in general stronger than those of other measures of hand function. These findings indicate that the MHQ reflects the patients opinions on changes in hand function better than other measures of hand function. With respect to the impact of the treatment on responsiveness, our separate analyses of surgically and conservatively treated RA patients suggest that the MHQ might be useful with various treatment strategies in patients with RA. So far, 5 studies evaluating the responsiveness of the MHQ have been published In one of these studies 8, 187 patients with various chronic hand disorders, including RA patients with severe deformities, were included. According to the correlation between change scores of the MHQ and its subscales and patients self-assessment of change it was concluded that the MHQ was responsive. The Spearman correlation coefficients found in that study were similar to those in the present study and ranged between.25 and.43. Although the magnitudes of the correlation coefficients were a bit smaller, more associations reached statistical significance in that study, which is probably due to the relatively larger sample size. No other measures of responsiveness were used in that study. In studies of patients undergoing metacarpophalangeal joint arthroplasty 10, distal radius fracture treatment 12, carpal tunnel surgery 11, or toe to thumb reconstruction after thumb amputation 9, the values of the measures of responsiveness used (effect size, SRM) were in the same range 12 or somewhat higher 8-11 than in the present study. The relatively favorable responsiveness of the MHQ satisfaction subscale found in the present study was consistent with the results of the study by Kotsis and Chung 11. Various studies have to be compared with caution, however, because any given study of responsiveness can only provide information about the ability of an outcome measure to detect the specific construct of change in a specific situation 28. Indeed, the previous studies on the responsiveness of the MHQ differed largely from the present study with respect to study design, patient population, treatment, and setting. In our study, the absolute magnitude of change of the MHQ total score differed significantly between patients who judged their hand function improved (+11.3 points) and patients who considered it as worsened (-3.9 points). This finding indicates that the instrument is not uniform over the range of possible outcomes and is probably more responsive to improvements than to deterioration. A limitation of the present study is the relatively small number of patients and the mix of interventions involved. It is conceivable that these factors may have increased the variation of the outcome measures, with a resulting negative impact on the responsiveness of all outcome measures. In addition, no conclusions on the responsiveness of the MHQ in specific treatment groups can be drawn. As responsiveness of outcome measures depends on the situation it is used for 29 ; generalizing the results of this study to patients with RA with less severe hand involvement should be done with some caution. Another limitation of the present study is that neither the patients nor the observer were blinded, so that a bias towards improvement might have been introduced. The inclusion of a control group without treatment might have enhanced the contrast between patients who judged their hand function as stable or deteriorated versus the patients who considered their hand function improved. 84

11 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis The favorable results of this study suggest that the MHQ is a useful instrument to evaluate hand function in patients with RA. An advantage of this instrument over other self-administered measures is the fact that it is multidimensional. Especially the domains aesthetics and work, which are very relevant for patients with RA, are not covered by other hand function questionnaires that are available so far. Advantages of using a questionnaire instead of a performance test is that no special equipment or trained assessors are required and that it is not time consuming. On the other hand, for some purposes, the observation of patients actually performing specific activities may provide information that is valuable to gain detailed insight into the nature and extent of complex hand function problems. The ultimate choice of measurement instruments for the evaluation of hand function in patients with RA in a specific situation will therefore, apart from the psychometric properties of an instrument, be dependent on multiple aspects, such as the desired level of detail of hand function disability and its underlying factors, the nature and goal of a therapeutic strategy if applicable, whether evaluations are performed on the group or on the individual level, and the availability of trained personnel. The responsiveness of the MHQ in patients with RA who received treatment in connection with a multidisciplinary hand clinic was good and compared favorable to other measures of hand function. To enhance the credibility of the results of this study, a larger population of patients should ideally have been included. If within each diagnosis category a sufficient number of patients had been evaluated, the responsiveness of the MHQ in various rheumatic diseases, other than RA, could have been established. With respect to the impact of the treatment on responsiveness, our separate analyses of surgically and conservatively treated RA patients suggest that in patients with RA the MHQ might be equally useful with various treatment strategies. 85

12 References 1. Maini RN, Feldman M. Rheumatoid arthritis. In: Maddison PJ, Isenberg DA, Woo P, Glass DN, editors. Oxford textbook of rheumatology. Oxford: Oxford Med Publications; p World Health Organization. International classification of functioning, disability and health: ICF. Geneva: WHO; Stucki G, Cieza A. The International Classification of Functioning, Disability and Health (ICF) Core Sets for rheumatoid arthritis: a way to specify functioning. Ann Rheum Dis 2004; 63(Suppl 2):ii Poole JL. Measures of adult hand function. Arthritis Care Res 2007; 49(5 Suppl):S Poole JL, Cordova KJ, Brower LM. Reliability and validity of a self-report of hand function in persons with rheumatoid arthritis. J Hand Ther 2006;19: Chung KC, Pillsbury MS, Walters MR, Hayward RA. Reliability and validity testing of the Michigan Hand Outcomes Questionnaire. J Hand Surg [Am] 1998; 23: Massy-Westropp N, Krishnan J, Ahern M. Comparing the AUSCAN Osteoarthritis Hand Index, Michigan Hand Outcomes Questionnaire, and Sequential Occupational Dexterity Assessment for patients with rheumatoid arthritis. J Rheumatol 2004; 31: Chung KC, Hamill JB, Walters MR, Hayward RA. The Michigan Hand Outcomes Questionnaire (MHQ): assessment of responsiveness to clinical change. Ann Plast Surg 1999; 42: Chung KC, Wei FC. An outcome study of thumb reconstruction using microvascular toe transfer. J Hand Surg [Am] 2000; 25: Chung KC, Kotsis SV, Kim HM. A prospective outcomes study of Swanson metacarpophalangeal joint arthroplasty for the rheumatoid hand. J Hand Surg [Am] 2004; 29: Kotsis SV, Chung KC. Responsiveness of the Michigan Hand Outcomes Questionnaire and the Disabilities of the Arm, Shoulder and Hand questionnaire in carpal tunnel surgery. J Hand Surg [Am] 2005; 30: Kotsis SV, Lau FH, Chung KC. Responsiveness of the Michigan Hand Outcomes Questionnaire and physical measurements in outcome studies of distal radius fracture treatment. J Hand Surg [Am] 2007; 32: Huijsmans R, Sluiter H, Aufdemkampe G. Michigan Hand Outcomes Questionnaire-Dutch Language Version; een vragenlijst voor patienten met handfunctieproblemen. Fysiopraxis 2001; 9: Tijhuis GJ, Zwinderman AH, Hazes JM, Van Den Hout WB, Breedveld FC, Vliet Vlieland TP. A randomized comparison of care provided by a clinical nurse specialist, an inpatient team, and a day patient team in rheumatoid arthritis. Arthritis Rheum 2002; 47: de Buck PD, Breedveld J, van der Giesen FJ, Vlieland TP. A multidisciplinary job retention vocational rehabilitation programme for patients with chronic rheumatic diseases: patients and occupational physicians satisfaction. Ann Rheum Dis 2004; 63: van der Giesen FJ, Nelissen RG, Rozing PM, et al. A multidisciplinary hand clinic for patients with rheumatic diseases: a pilot study. J Hand Ther 2007; 20:251-60; quiz Riemsma RP, Taal E, Rasker JJ, Houtman PM, Van Paassen HC, Wiegman O. Evaluation of a Dutch version of the AIMS2 for patients with rheumatoid arthritis. Br J Rheumatol 1996; 35: van Lankveld W, van t Pad Bosch P, Bakker J, Terwindt S, Franssen M, van Riel P. Sequential occupational dexterity assessment (SODA): a new test to measure hand disability. J Hand Ther 1996; 9: van Lankveld W, van t Pad Bosch P, van der Schaaf D, Dapper M, de Waal Malefijt M, van de Putte L. Evaluating hand surgery in patients with rheumatoid arthritis: short-term effect on dexterity and pain and its relationship with patient satisfaction. J Hand Surg [Am] 2000; 25: van Lankveld WG, Graff MJ, van t Pad Bosch PJ. The Short Version of the Sequential Occupational Dexterity Assessment based on individual tasks sensitivity to change. Arthritis Care Res 1999; 12: Harkonen R, Harju R, Alaranta H. Accuracy of the Jamar dynamometer. J Hand Ther 1993; 6: Mathiowetz V, Kashman N, Volland G, Weber K, Dowe M, Rogers S. Grip and pinch strength: normative data for adults. Arch Phys Med Rehabil 1985; 66: Guyatt G, Walter S, Norman G. Measuring change over time:assessing the usefulness of evaluative 86

13 Responsiveness of the Michigan Hand Outcomes Questionnaire - Dutch Language Version in Patients With Rheumatoid Arthritis instruments. J Chronic Dis 1987; 40: Wanders AJ, Gorman JD, Davis JC, Landewe RB, van der Heijde DM. Responsiveness and discriminative capacity of the assessments in ankylosing spondylitis disease-controlling antirheumatic therapy core set and other outcome measures in a trial of etanercept in ankylosing spondylitis. Arthritis Rheum 2004; 51: Liang MH, Lew RA, Stucki G, Fortin PR, Daltroy L. Measuring clinically important changes with patientoriented questionnaires. Med Care 2002; 40(4 Suppl):II Terwee CB, Bot SD, de Boer MR, et al. Quality criteria were proposed for measurement properties of health status questionnaires. J Clin Epidemiol 2007; 60: Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Mahwah: Lawrence Erlbaum; Beaton DE, Bombardier C, Katz JN, et al. Looking for important change/differences in studies of responsiveness. OMERACT MCID Working Group. Outcome measures in rheumatology. Minimal clinically important difference. J Rheumatol 2001; 28: Beaton DE, Bombardier C, Katz JN, Wright JG. A taxonomy for responsiveness. J Clin Epidemiol 2001; 54: Supplier a. JA Preston Corp, 60 Page Rd, Clifton, NJ

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