Heleen Beckerman

How to measure comorbidity. a critical review of available methods.

The object of this article was to systematically review available methods to measure comorbidity and to assess their validity and reliability. A search was made in Medline and Embase, with the keywords comorbidity and multi-morbidity, to identify articles in which a method to measure comorbidity was described. The references of these articles were also checked, and using a standardized checklist the relevant data were extracted from these articles. An assessment was made of the content, concurrent, predictive and construct validity, and the reliability. Thirteen different methods to measure comorbidity were identified: one disease count and 12 indexes. Data on content and predictive validity were available for all measures, while data on construct validity were available for nine methods, data on concurrent validity, and interrater reliability for eight methods, and data on intrarater reliability for three methods. The Charlson Index is the most extensively studied comorbidity index for predicting mortality. The Cumulative Illness Rating Scale (CIRS) addresses all relevant body systems without using specific diagnoses. The Index of Coexisting Disease (ICED) has a two-dimensional structure, measuring disease severity and disability, which can be useful when mortality and disability are the outcomes of interest. The Kaplan Index was specifically developed for use in diabetes research. The Charlson Index, the CIRS, the ICED and the Kaplan Index are valid and reliable methods to measure comorbidity that can be used in clinical research. For the other indexes, insufficient data on the clinimetric properties are available.

Smallest real difference, a link between reproducibility and responsiveness.

The aim of this study is to show the relationship between test-retest reproducibility and responsiveness and to introduce the smallest real difference (SRD) approach, using the sickness impact profile (SIP) in chronic stroke patients as an example. Forty chronic stroke patients were interviewed twice by the same examiner, with a 1-week interval. All patients were interviewed during the qualification period preceding a randomized clinical trial. Test-retest reproducibility has been quantified by the intraclass correlation coefficient (ICC), the standard error of measurement (SEM) and the related smallest real difference (SRD). Responsiveness was defined as the ratio of the clinically relevant change to the SD of the within-stable-subject test-retest differences. The ICC for the total SIP was 0.92, whereas the ICCs for the specified SIP categories varied from 0.63 for the category ‘recreation and pastime’ to 0.88 for the category ‘work’. However, both the SEM and the SRD far more capture the essence of the reproducibility of a measurement instrument. For instance, a total SIP score of an individual patient of 28.3% (which is taken as an example, being the mean score in the study population) should decrease by at least 9.26% or approximately 13 items, before any improvement beyond reproducibility noise can be detected. The responsiveness to change of a health status measurement instrument is closely related to its test-retest reproducibility. This relationship becomes more evident when the SEM and the SRD are used to quantify reproducibility, than when ICC or other correlation coefficients are used.

Minimal changes in health status questionnaires: distinction between minimally detectable change and minimally important change

Changes in scores on health status questionnaires are difficult to interpret. Several methods to determine minimally important changes (MICs) have been proposed which can broadly be divided in distribution-based and anchor-based methods. Comparisons of these methods have led to insight into essential differences between these approaches. Some authors have tried to come to a uniform measure for the MIC, such as 0.5 standard deviation and the value of one standard error of measurement (SEM). Others have emphasized the diversity of MIC values, depending on the type of anchor, the definition of minimal importance on the anchor, and characteristics of the disease under study. A closer look makes clear that some distribution-based methods have been merely focused on minimally detectable changes. For assessing minimally important changes, anchor-based methods are preferred, as they include a definition of what is minimally important. Acknowledging the distinction between minimally detectable and minimally important changes is useful, not only to avoid confusion among MIC methods, but also to gain information on two important benchmarks on the scale of a health status measurement instrument. Appreciating the distinction, it becomes possible to judge whether the minimally detectable change of a measurement instrument is sufficiently small to detect minimally important changes.

Clinimetric Properties of the Motor Activity Log for the Assessment of Arm Use in Hemiparetic Patients

Background and Purpose— The Motor Activity Log (MAL) is a semistructured interview for hemiparetic stroke patients to assess the use of their paretic arm and hand (amount of use [AOU]) and quality of movement [QOM]) during activities of daily living. Scores range from 0 to 5. The following clinimetric properties of the MAL were quantified: internal consistency (Cronbach α), test–retest agreement (Bland and Altman method), cross-sectional construct validity (correlation between AOU and QOM and with the Action Research Arm [ARA] test), longitudinal construct validity (correlation of change on the MAL during the intervention with a global change rating [GCR] and with change on the ARA), and responsiveness (effect size). Methods— Two baseline measurements 2 weeks apart and 1 follow-up measurement immediately after 2 weeks of intensive exercise therapy either with or without immobilization of the unimpaired arm (forced use) were performed in 56 chronic stroke patients. Results— Internal consistency was high (AOU: α=0.88; QOM: α=0.91). The limits of agreement were −0.70 to 0.85 and −0.61 to 0.71 for AOU and QOM, respectively. The correlation with the ARA score (Spearman ρ) was 0.63 (AOU and QOM). However, the improvement on the MAL during the intervention was only weakly related to the GCR and to the improvement on the ARA, Spearman ρ was between 0.16 and 0.22. The responsiveness ratio was 1.9 (AOU) and 2.0 (QOM). Conclusion— The MAL is internally consistent and relatively stable in chronic stroke patients not undergoing an intervention. The cross-sectional construct validity of the MAL is reasonable, but the results raise doubt about its longitudinal construct validity.

The responsiveness of the Action Research Arm test and the Fugl-Meyer Assessment scale in chronic stroke patients.

The responsiveness of the Action Research Arm (ARA) test and the upper extremity motor section of the Fugl-Meyer Assessment (FMA) scale were compared in a cohort of 22 chronic stroke patients undergoing intensive forced use treatment aimed at improvement of upper extremity function. The cohort consisted of 13 men and 9 women, median age 58.5 years, median time since stroke 3.6 years. Responsiveness was defined as the sensitivity of an instrument to real change. Two baseline measurements were performed with a 2-week interval before the intervention, and a follow-up measurement after 2 weeks of intensive forced use treatment. The limits of agreement, according to the Bland-Altman method, were computed as a measure of the test-retest reliability. Two different measures of responsiveness were compared: (i) the number of patients who improved more than the upper limit of agreement during the intervention; (ii) the responsiveness ratio. The limits of agreement, designating the interval comprising 95% of the differences between two measurements in a stable individual, were -5.7 to 6.2 and -5.0 to 6.6 for the ARA test and the FMA scale, respectively. The possible sum scores range from 0 to 57 (ARA) and from 0 to 66 (FMA). The number of patients who improved more than the upper limit were 12 (54.5%) and 2 (9.1%); and the responsiveness ratios were 2.03 and 0.41 for the ARA test and the FMA scale, respectively. These results strongly suggest that the ARA test is more responsive to improvement in upper extremity function than the FMA scale in chronic stroke patients undergoing forced use treatment.

Physiotherapy exercises and back pain: a blinded review.

OBJECTIVE--To determine the quality of randomised controlled trials of exercise therapy for back pain. DESIGN--Computer aided search of published papers and blinded assessment of the methods of studies. SUBJECTS--23 randomised controlled trials, of which 16 studied exercise therapy given by physiotherapists to individual patients with back pain. Other conservative treatments could be included. MAIN OUTCOME MEASURES--Score for quality of methods (based on four main categories: study population, interventions, measurement of effect, and data presentation and analysis) and main conclusion of author(s) with regard to exercise therapy. RESULTS--Only four studies scored more than 50 points (maximum 100), indicating that most were of poor quality. Six studies found that exercise was better than reference treatments and 10 reported it to be no better or worse than the reference treatment. Those reporting positive results tended to have higher methods scores (4/6 positive v 4/10 negative scored greater than or equal to 42). CONCLUSIONS--No conclusion can be drawn about whether exercise therapy is better than other conservative treatments for back pain or whether a specific type of exercise is more effective. Further trials are needed in which greater attention is paid to methods of study.

Exercise therapy for arm function in stroke patients: a systematic review of randomized controlled trials

Objective: Assessment of the available evidence for the effectiveness of exercise therapy to improve arm function in patients who have suffered from a stroke. Methods: A systematic search of bibliographical databases and reference checking were performed to identify publications on randomized controlled trials (RCTs) which evaluated the effect of exercise therapy on arm function in stroke patients. The methodological quality was assessed systematically by two raters, based on a standardized list of methodological criteria. Study characteristics, such as the chronicity and severity of impairment of the patient population, the amount and duration of interventions, and specific methodological criteria, were related to reported effects. Results: Thirteen RCTs were identified, six of which reported positive results on an arm function test. In five of these six studies there was a contrast in amount or duration of exercise therapy between groups. Methodological scores ranged from 5 to 15 (maximum possible score: 19 points). Conclusion: Insufficient evidence made it impossible to draw definitive conclusions about the effectiveness of exercise therapy on arm function in stroke patients. The difference in results between studies with and without contrast in the amount or duration of exercise therapy between groups suggests that more exercise therapy may be beneficial.

Minimally important change determined by a visual method integrating an anchor-based and a distribution-based approach

Background:Minimally important changes (MIC) in scores help interpret results from health status instruments. Various distribution-based and anchor-based approaches have been proposed to assess MIC.Objectives:To describe and apply a visual method, called the anchor-based MIC distribution method, which integrates both approaches.Method:Using an anchor, patients are categorized as persons with an important improvement, an important deterioration, or without important change. For these three groups the distribution of the change scores on the health status instrument are depicted in a graph. We present two cut-off points for an MIC: the ROC cut-off point and the 95% limit cut-off point.Results:We illustrate our anchor-based MIC distribution method determining the MIC for the Pain Intensity Numerical Rating Scale in patients with low back pain, using two conceivable definitions of minimal important change on the anchor. The graph shows the distribution of the scores of the health status instrument for the relevant categories on the anchor, and also the consequences of choosing the ROC cut-off point or the 95% limit cut-off point.Discussion:The anchor-based MIC distribution method provides a general framework, applicable to all kind of anchors. This method forces researchers to choose and justify their choice of an appropriate anchor and to define minimal importance on that anchor. The MIC is not an invariable characteristic of a measurement instrument, but may depend, among other things, on the perspective from which minimal importance is considered and the baseline values on the measurement instrument under study. A balance needs to be struck between the practicality of a single MIC value and the validity of a range of MIC values.

Effect of Triamcinolone Acetonide Injections on Hemiplegic Shoulder Pain: A Randomized Clinical Trial

Background and Purpose Hemiplegic shoulder pain is not uncommon after stroke. Its origin is still unknown, and although many different methods of treatment are applied, none have yet been proved to be effective. We sought to study the efficacy of 3 injections of intra-articular triamcinolone acetonide on pain and arm function in stroke patients with hemiplegic shoulder pain. Methods In a multicenter, randomized, placebo-controlled clinical trial, patients with hemiplegic shoulder pain received either 3 intra-articular injections of 40 mg triamcinolone acetonide or 1 mL physiological saline solution (placebo). Primary outcomes were pain measured according to 3 visual analogue scales (score range, 0 to 10), and arm function was measured by means of the Action Research Arm test and the Fugl-Meyer assessment scale; secondary outcomes were passive external rotation of the shoulder and general functioning measured according to Barthel Index and the Rehabilitation Activities Profile. Results In the triamcinolone group (n=18), the median decrease in pain, 3 weeks after the last injection, was 2.3 (interquartile range, 0.3 to 4.3) versus 0.2 (interquartile range, −0.5 to 2.2) in the placebo group. This result was not statistically significant. The change in the other outcome measures did not differ significantly between the 2 treatment groups. Twenty-five patients reported side effects. Conclusions In the 37 participants included in this study, triamcinolone injections seemed to decrease hemiplegic shoulder pain and to accelerate recovery, but this effect was not statistically significant. Therefore, on the basis of the results of this study, these injections cannot be recommended for the treatment of patients with hemiplegic shoulder pain.

Physical Activity Behavior of People With Multiple Sclerosis: Understanding How They Can Become More Physically Active

Background People with multiple sclerosis (MS) are less physically active than those without the disease. Understanding the modifiable factors that are related to physical inactivity is important for developing effective physical activity programs. Objective The objectives of this study were to determine levels of physical activity and to determine factors related to the physical activity behavior of adults with MS by use of the Physical Activity for People With a Disability (PAD) model. The PAD model combines the International Classification of Functioning, Disability and Health framework of disability and theoretical models of physical activity behavior. Design This investigation was a cross-sectional study. Methods The study participants were 106 people who had MS and who, since their definite diagnosis, had been participating in a prospective cohort study. Physical activity was assessed with the Short Questionnaire to Assess Health-Enhancing Physical Activity. The independent roles of disease characteristics and demographic, cognitive-behavioral, and environmental factors were determined using questionnaires for which reliability and validity have been established. Results The median total level of physical activity of participants with MS (mean age=42.8 years, median Expanded Disability Status Scale score=3, disease duration=6 years) was 10.68 metabolic equivalents × h/d (interquartile range=3.69–16.57). On average, participants spent 30 h/wk on activities with metabolic equivalents of 2 or more (interquartile range=10.7–45.0 h/wk). The regression models predicting physical activity behavior on the basis of demographic (29.4%) and disease-related (28.3%) variables explained more variance than the models based on cognitive-behavioral (12.0%) and environmental (9.1%) variables. Combining significant variables yielded a final regression model that explained 37.2% of the variance in physical activity. Significant determinants were disease severity, a disability pension, and having children to care for. Limitations Changes in physical activity behavior were not measured. Conclusions Participants with MS were less active if their disease was more severe, if they received a disability pension, or if they had children to care for. The PAD model was helpful in understanding the physical activity behavior of participants with MS.