Minimal clinically important difference for 7 measures of fatigue in patients with systemic lupus erythematosus

OBJECTIVE

To determine the minimal clinically important difference (MCID) for 7 measures of fatigue in patients with systemic lupus erythematosus (SLE).

METHODS

Study subjects completed 7 fatigue instruments [Fatigue Severity Scale (FSS), Multidimensional Assessment of Fatigue (MAF), Multidimensional Fatigue Inventory (MFI), Vitality scale of the MOS-SF-36, Chalder Fatigue Scale (CFS), Functional Assessment of Chronic Illness Therapy-Fatigue, and a global Rating Scale (RS)] and then participated in a series of interviews with other study participants comparing their fatigue with one another. Each interview participant rated the difference in their fatigue levels on a 7-point transition scale. The MCID was estimated from the mean difference in fatigue scores between each pair of interview participants based on their subjective rating of fatigue contrast. The MCID was also estimated using linear regression modeling.

RESULTS

Eighty patients with SLE participated. Patients reported significant levels of fatigue [mean normalized (0 = none, 100 = maximum) fatigue scores for the 7 instruments ranged from 49.8 (CFS) to 71.1 (FSS)]. The MCID of "a little more" fatigue tended to be greater than the MCID for a "little less fatigue" and differed significantly for FSS and MAF. The MCID of normalized scores estimated by linear regression ranged from 7.0 (CFS) to 14.3 (MFI).

CONCLUSION

Fatigue is a common and debilitating component of SLE. Estimates of MCID will help to interpret changes observed in a fatigue score and will be critical in estimating sample size requirements for clinical trials including fatigue as an outcome.

Determination of the minimal clinically important difference for seven fatigue measures in rheumatoid arthritis

OBJECTIVE

To estimate the minimal clinically important difference (MCID) of seven measures of fatigue in rheumatoid arthritis.

STUDY DESIGN AND SETTING

A cross-sectional study design based on interindividual comparisons was used. Six to eight subjects participated in a single meeting and completed seven fatigue questionnaires (nine sessions were organized and 61 subjects participated). After completion of the questionnaires, the subjects had five one-on-one 10-minute conversations with different people in the group to discuss their fatigue. After each conversation, each patient compared their fatigue to their conversational partners on a global rating. Ratings were compared to the scores of the fatigue measures to estimate the MCID. Both nonparametric and linear regression analyses were used.

RESULTS

Nonparametric estimates for the MCID relative to "little more fatigue" tended to be smaller than those for "little less fatigue." The global MCIDs estimated by linear regression were: Fatigue Severity Scale, 20.2; Vitality scale of the MOS-SF36, 14.8; Multidimensional Assessment of Fatigue, 18.7; Multidimensional Fatigue Inventory, 16.6; Functional Assessment of Chronic Illness Therapy-Fatigue, 15.9; Chalder Fatigue Scale, 9.9; 10-point numerical Rating Scale, 19.7, for normalized scores (0-100). The standardized MCIDs for the seven measures were roughly similar (0.67-0.76).

CONCLUSION

These estimates of MCID will help to interpret changes observed in a fatigue score and will be critical in estimating sample size requirements.

Perceptions in 7700 patients with rheumatoid arthritis compared to their families and physicians

OBJECTIVE

To compare perceptions of patients with rheumatoid arthritis (RA) to those of their families and usual physicians regarding pain and subjective experience of the disease.

METHODS

Questionnaires were mailed to patients listed in the files of a non-profit patient organization (Association Française des Polyarthritiques). Each patient, one family member (or close friend), and the usual physician were each asked to complete a questionnaire. Concordance among replies made by patients, family/friends, and physicians was evaluated using the kappa coefficient.

RESULTS

Questionnaires were sent to 20,468 patients, among whom 7702 (38%) mailed back adequate data. The family member was usually the spouse (70%) and the usual physician a rheumatologist (68%). Joint pain was described by patients as variable (80%) and unpredictable (68%). Patients reported a need to push themselves (86%), frustration (86%), anxiety about possible disease progression (89%), and being prevented from making plans for the future (6%). A negative impact was reported on recreational activities (84%), work (56%), and family life and sexuality (51%). Concordance was excellent for pain severity (kappa>0.90) and good for the main joint-pain characteristics and experience of the disease (kappa>0.70), although family members tended to overestimate, and physicians to underestimate, the intensity of the pain.

CONCLUSION

We found good overall agreement between perceptions of patients, their families, and their physicians, despite differences between these last two groups. Our qualitative analysis showed not only a major physical impact of the disease, but also marked negative psychosocial effects.

Content of quality-of-life instruments is affected by item-generation methods

BACKGROUND

Methods used to generate items for complex measurement scales are heterogeneous and probably produce heterogeneous data, yet nothing is known about the advantages of one method over another.

OBJECTIVE

We aimed to compare methods of generating items for tools designed to measure quality-of-life for patients.

METHODS

We used five methods to develop a quality-of-life instrument for patients with lower-limb osteoarthritis: individual interviews with patients involving two different techniques (semi-structured and cognitive), individual interviews with health professionals, and focus groups of patients and health professionals. The process generated 80 items, of which 37 were excluded after content and psychometric analysis. With the final 43-item scale used as a 'reference standard', we estimated the contribution of each method.

RESULTS

For health professionals, the focus group and individual interviews produced 35 and 81% of the items, respectively. For patients, the focus groups produced 74% of the items and both interview techniques 100% of the items. Health professionals provided a narrower picture of the effects of the disease on quality-of-life. Focus groups contributed less to social domains than did individual interviews. The two patient interview techniques highlighted different themes.

CONCLUSION

In developing a complex measurement scale for patients, we found individual interviews with patients the best method for formulating items; other methods such as physician interviews and focus groups contributed no additional information. Reports of instrument generation should include details of the item-generation step, the methods used to develop items and the number of people involved.

Rhabdomyolyse massive révélant une maladie de McArdle

INTRODUCTION

McArdle's disease is an autosomal recessive glycogenosis caused by deficiency of muscle glycogen phosphorylase resulting in glycogen accumulation in the skeletal muscle. Typically, McArdle's disease is characterized by exercise intolerance with muscle cramps and myoglobinuria.

CASE REPORT

We report a 20-year-old woman with massive rhabdomyolysis and acute renal failure revealing a McArdle's disease.

DISCUSSION

Although muscle impairment is constant in McArdle's disease, massive rhabdomyolysis with severe acute renal failure has been rarely reported as a presenting feature. The mechanisms and therapeutic implications of renal injury are discussed.

A Gray Zone Assigned to Inconclusive Results of Quantitative Diagnostic Tests: Application to the Use of Brain Natriuretic Peptide for Diagnosis of Heart Failure in Acute Dyspneic Patients

Background: Most quantitative diagnostic tests do not perfectly differentiate between persons with and without a given disease. We present a simple method to construct a 3-zone partition for quantitative tests results, including positive and negative zones and a gray zone between, and we describe its use in the diagnosis of heart failure by brain natriuretic peptide (BNP) measurement in acute dyspneic patients.

Methods: We conducted a prospective cohort study of 699 consecutive patients with acute dyspnea who were treated at the emergency department of 3 participating hospitals. Heart failure (acute or decompensated) was assessed independently at discharge by cardiologists blind to the results of BNP measurements.

Results: The discriminatory performance of BNP was insufficient to provide a single cutoff value that could be used to correctly diagnose heart failure in clinical practice. Also, the discriminatory performance differed between patients with and without a history of chronic heart failure. The gray zone of inconclusive results was 167–472 ng/L for those without and 0–334 ng/L for those with such a history. Diagnosis of the current episode of heart failure by BNP results and history of heart failure was not enhanced by data from any other sources, including electrocardiography.

Conclusions: The gray zone approach applied to the diagnosis of heart failure by BNP might allow sensible cutoff values to be determined for clinical practice according to relevant subgroups of patients. The gray zone approach might be usefully applied to many other quantitative tests and clinical diagnostic or screening problems.

Development and testing of a specific quality-of-life questionnaire for knee and hip osteoarthritis: OAKHQOL (OsteoArthritis of Knee Hip Quality Of Life)

OBJECTIVE

To design a quality-of-life (QOL) instrument specific for patients with knee or hip osteoarthritis and to assess its validity and reproducibility.

METHODS

One-on-one or group interviews were conducted with 79 patients and 28 healthcare professionals. Of the 80 potential items identified from the results, 46 were selected based on their content and were used to develop version 1 of the OsteoArthritis of Knee and Hip Quality of Life Scale (OAKHQOL). The psychometric characteristics of the scale were evaluated in patients who met Altman's criteria for knee or hip osteoarthritis.

RESULTS

Based on the results of psychometric analyses in 263 patients, three items were excluded, leaving 43 items in the final version (2.3) of the OAKHQOL. Principal components analysis identified four domains: physical activities, mental health, social functioning, and social support. A pain domain was individualized later. Construct validity, reproducibility, and discriminating power of the domains were satisfactory. Standardized response means after joint replacement surgery were close to 1 for the pain and physical functioning domains and equal to 0.7 for the mental health domain, indicating good sensitivity to change.

CONCLUSIONS

The OAKHQOL is the first QOL tool specifically dedicated to lower-limb osteoarthritis. It captures specific aspects of QOL in patients with knee or hip osteoarthritis and exhibits psychometric properties consistent with use in longitudinal studies.

Role for positron emission tomography in skeletal diseases

Imaging plays a prominent role in the diagnosis and management of rheumatic diseases. Conventional imaging methods provide high-resolution structural information but usually fail to distinguish between active lesions and residual changes. Positron emission tomography (PET) with the tracer 18F-fluorodeoxyglucose (18F-FDG) was recently introduced into clinical practice as a means of obtaining information on both structure and metabolic activity. 18F-FDG-PET is widely used in oncology and may be valuable in patients with infections or inflammatory diseases, most notably vasculitis. Although encouraging results have been published, the number of studies remains small, as 18F-FDG-PET is an expensive investigation that is not available everywhere. Further work is needed to determine the cost-effectiveness ratio of 18F-FDG-PET in patients with infections or inflammatory diseases. Imaging plays a prominent role in the diagnosis and management of many musculoskeletal diseases. Although considerable progress has been made recently, the structural information supplied by conventional imaging methods is inadequate in some patients. Positron emission tomography (PET) after injection of 18fluorodeoxyglucose (18F-FDG) provides information on tissue metabolism. The usefulness of 18F-FDG-PET in oncology is now widely recognized. Other uses are emerging, in part thanks to the development of new cameras that combine dedicated detectors and an X-scanner in order to ensure accurate three-dimensional localization of metabolically active lesions. However, the exact role for 18F-FDG-PET needs to be studied in larger populations of patients.

Pulmonary arterial hypertension in ANCA-associated vasculitis

BACKGROUND AND AIM OF THE WORK

Pulmonary arterial hypertension (PAH) is a severe condition characterized by chronic obstruction of small pulmonary arteries leading to progressive right heart failure and ultimately death. Inflammatory mechanisms may play an important part in the origin or progression of the disease in a subset of patients. Whereas PAH is well known complication of some connective tissue diseases, it is a rare condition associated with systemic vasculitis. In the present report, we describe 4 cases of anti-neutrophil cytoplasmic antibodies (ANCA)-related systemic vasculitis (3 with Wegener's granulomatosis and 1 with microscopic polyangiitis) associated with PAH.

METHODS

We describe the clinical features of both ANCA-associated systemic vasculitis and PAH.

RESULTS

PAH was diagnosed after the onset of the systemic vasculitis in 3 cases. In 1 case, the systemic vasculitis was active at the diagnosis of PAH and treatment of the vasculitis led to a significant improvement of PAH. In the 2 other patients, PAH occurred while the vasculitis was inactive. The remaining patient, for whom Wegener's granulomatosis was diagnosed 2 years after PAH was documented, died because of a vasculitis treatment-related side effect.

CONCLUSIONS

Systemic vasculitides have to be added to the conditions associated with PAH. The underlying pathophysiological mechanisms of this association have still to be firmly established. It is probable that some PAH are due, at least in part, to direct pulmonary arteries involvement by the vasculitic process.

Impact of pain in health related quality of life of patients with systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) has an heterogenous clinical pattern, with variable organ involvement and degrees of severity. Like in other rheumatic diseases, the self-questionnaires have been used to evaluate SSc globally. The aim of the study is as to evaluate the quality of life (QoL) in patients with either diffuse or limited SSc, and to examine the impact of pain on the QoL scores.

METHODS

Patients with SSc, either diffuse or limited SSc, were included in a cross-sectional study. The QoL was evaluated with the short-form 36 (SF-36) and the functional repercussion with the SSc-modified Health Assessment Questionnaire (S-HAQ).

RESULTS

A total of 89 patients (67 with diffuse and 22 with limited SSc) were included. The SF-36 score values were lower in SSc patients than those reported in the general population. The physical component scores (PCS) of the SF-36 was significantly worse in diffuse compared with limited SSc (P < 0.05). The PCS was significantly negatively related to the number of clinical manifestations (ANOVA, P < 0.0001). The mental component score (MCS) was not influenced by the type of SSc or the number of clinical manifestations presented by the patient. The QoL of SSc patients was highly correlated with pain (R = 0.69) and disability (R = 0.70). Interestingly, the QoL of SSc patients was only slightly correlated with cutaneous (R = 0.42) and pulmonary involvement (R = 0.57).

CONCLUSION

The QoL of patients with SSc is strongly influenced by the type of SSc, the burden of clinical manifestations, the functional disability and by the pain, whatever its cause. The treatment of pain should be considered as priority to improve the QoL of SSc patients.

[Adult-onset Still's disease revealed by a pericardial tamponade: report of two cases]

INTRODUCTION

Adult onset Still's disease is a systemic inflammatory disorder of unknown etiology characterized by the association of a high spiking fever, an evanescent skin rash, arthritis, and hyperleukocytosis. Pericarditis is amongst the most common systemic manifestations of adult onset Still's disease.

EXEGESIS

We report on two patients with a pericardial tamponade revealing an adult onset Still's disease in a 52-year-old female and a 31-year-old male. Pericardial fluid was bloody in the two cases, and histopathology only disclosed non specific inflammatory changes. Both patients received corticosteroids and outcome was uneventful with a follow-up of 8 years and 12 months, respectively.

CONCLUSION

Pericardial tamponade is an uncommon clinical feature of adult-onset Still's disease and usually occurs at disease onset. It makes the diagnosis of adult-onset Still's disease difficult as the other disease manifestations are commonly neglected. Adult onset Still's disease should be added to the differential of acute pericarditis and tamponade.

[From familial Mediterranean fever to amyloidosis]

The progression of familial Mediterranean fever is marked by the recurrence, at varying intervals, of acute flares that regress spontaneously. Prognosis, which depends on the occurrence of amyloidosis, has been transformed by colchicine treatment. Incidence of amyloidosis is higher in certain ethnic groups (Jews from North Africa, Turks) and depends on by the specific MEFV mutation. Amyloid is composed of clusters of protein strands identical to the AA protein of secondary amyloidosis and infiltrates the walls of all arterioles except those of the central nervous system. The earliest and most consistent localization is in the kidney, where it develops over several years and in 4 stages--preclinical (latency), proteinuric, nephrotic and uremic--before concluding in end-state renal failure. Before the advent of colchicine, dialysis and transplantation, only renal amyloidosis caused clinical manifestations and lethal complications; any amyloidosis at any other sites remained latent. Prolonged survival with hemodialysis and kidney transplantation now leaves time for manifestation of these other localizations, such as infiltration into the intestines causing malabsorption, or potentially lethal cardiac lesions. Treatment of familial Mediterranean fever is based on the continuous administration of colchicine, which at the average dose of 1 to 2 mg per day can prevent flares or at least reduce their frequency or intensity. Systematic use of colchicine also prevents the onset of amyloidosis, even in the rare cases where it cannot prevent flares. These data fully justify the systematic use of colchicine for continuous prophylactic treatment from diagnosis and even after kidney transplantation, to prevent recurrence of the grafted kidney or extension to other organs. The curative efficacy of colchicine on flares is debatable, although several studies report positive results against progression of early amyloidosis.

[Familial Mediterranean fever among the autoimmune diseases]

During the first attacks of familial Mediterranean fever, each of the disease symptoms can suggest a series of disorders. When the disease is older, the recurrence of symptoms may simulate some systemic diseases, but mainly suggests familial Mediterranean fever, one of a group of hereditary autoinflammatory diseases. Before the gene for familial Mediterranean fever was identified, various sets of criteria were used for diagnosis. The presence of MEFV mutations confirms the diagnosis, but the clinical criteria still determine who should undergo this genetic testing. The genotype-phenotype correlations add a prognostic dimension to the mutations identified. Genotyping can also lead to the diagnosis of the other autoinflammatory diseases, which constitute the basis of the differential diagnosis of familial Mediterranean fever. The hyperimmunoglobulinemia D syndrome (HIDS) is very similar to familial Mediterranean fever in its recessive transmission and abdominal and articular symptoms. It can be distinguished by the European origin of the patients, the presence of cervical lymph nodes and the increased IgD levels. Of the diseases with dominant transmission, the TNF receptor-associated periodic syndromes (TRAPS) are suggested by periorbital edema and migrating inflammatory cellulitis. Muckle and Wells syndrome is revealed by episodes of fever with urticaria and arthralgia, complicated by deafness and amyloidosis. Mutations in the same gene are responsible for two disorders, both appearing in childhood: familial cold urticaria syndrome (FCUS) and chronic infantile neurocutaneous articular syndrome (CINC). The pathogenesis of familial Mediterranean fever is still unclear. Pyrin/marenostrin, the protein produced by the MEFV gene, appears to hae a physiological antiinflammatory effect that inhibits proinflammatory cytokines. Mutation of the gene may eliminate this feedback mechanism and expose the patient to flares from any inflammatory stimulus, even minimal. Amyloid is produced by the serum amyloid A protein (SAA), and its occurrence is influenced by the type of MEFV mutation, but also the genotype of the gene producing SAA.

Maladie périodique, symptomatologie clinique et biologique

Familial Mediterranean fever is the best known of the recurrent hereditary autoinflammatory diseases. It predominantly affects subjects of Mediterranean origin, Sephardic Jews in particular. Its gene, MEFV, is located on chromosome 16 and has autosomal recessive transmission, with incomplete penetration. It codes for a protein called pyrin or marenostrin, which is probably involved in the inflammatory process. In most cases, the first episodes appear before the age of 20 years and very rarely after the age of 40. Episodes usually last a few days, although they may extent over several weeks when localized in joints. Fever, occasionally pseudo-malaria, may accompany various symptoms, the most frequent of which are abdominal, articular, pleural or cutaneous. The abdomen is the classic site of this disease, and acute abdominal flares masquerade as abdominal emergencies. Musculoskeletal involvement is revealed by episodes of inflammation of the joints (more often mono- than oligoarthritis) and muscle pain. The flares are usually brief and totally reversible. Flares of thoracic pain corresponding to pleural inflammation and erysipelas-like skin eruptions have been observed. Acute symptoms disappear between flares, but hepatic splenomegaly, swollen lymph nodes or abnormal fundus of the eye may persist. Laboratory findings are typical of nonspecific inflammation, accompanied by moderate hyperleukocytosis during the flares.

Development and psychometric validation of a new patient satisfaction instrument: The osteoARthritis Treatment Satisfaction (ARTS) questionnaire

Given the increasing interest in treatment satisfaction research and the lack of a specific questionnaire in osteoarthritis (OA), we developed and explored the psychometric properties of the osteoARthritis Treatment Satisfaction (ARTS) questionnaire. The ARTS questionnaire which consists of 18 items was developed in French following the analysis of semi-structured interviews performed among 20 OA participants, five rheumatologists and five general practitioners. Psychometric properties were assessed in France on a cross-sectional sample of 797 OA participants and test-retest reliability was evaluated in an independent sample of 111 clinically stable OA participants who filled-in the questionnaire within a 7.7 (+/- 3.1) day interval. Using principal component analysis, four scales were identified: Treatment advantages (seven items), Treatment convenience (three items), Treatment confidence (two items) and Satisfaction with physician (six items). Item convergent and item discriminant validity were satisfactory. Internal consistency provided evidence of reliability and lack of redundancy (Cronbach's alphas ranged from 0.66 to 0.86). Test-retest reliability was acceptable for two out of four scales (intraclass correlations coefficients (ICC) ranged from 0.61 to 0.75). Significant between groups differences were found on the ARTS scales, demonstrating the known groups validity of the ARTS questionnaire. The responsiveness of the ARTS is still to be documented.

Methodological issues in determining the dimensionality of composite health measures using principal component analysis: Case illustration and suggestions for practice

During the early steps of the construction of composite health measures, principal component analysis (PCA) is commonly used to identify 'latent' factors that underlie observed variables and to determine the dimensionality of the instruments. The determination of the number of components to retain is critical to PCA: it markedly influences the factorial model identified and further conditions the validity of the constructed instrument. However, many researchers developing composite health measures seem to be unaware of the importance of this determination. The purposes of the paper are to illustrate (1) the variability of the factorial models obtained by using different published rules (n = 10) for determining the number of components to retain in PCA applied to two quality-of-life datasets, and (2) the value of a careful and diversified approach to the problem of the number of components to retain in PCA that we suggest, instead of the unsatisfactory 'rule-of-thumb' that many researchers use. This involves: (1) using robust rules (including parallel analysis and minimum average partial procedure) to generate a set of possible values for the number of components to retain, (2) repeating the analysis across samples, (3) comprehensively assessing the models obtained, and (4) considering complementary methods to PCA and especially confirmatory factor analysis.

OAKHQOL: A new instrument to measure quality of life in knee and hip osteoarthritis

OBJECTIVE

To develop a questionnaire with which to measure quality of life (QoL) in patients with knee and hip osteoarthritis (OA).

STUDY DESIGN AND SETTING

Thirty-two caregivers and 96 OA patients were interviewed individually (using cognitive and face-to-face techniques) and in focus groups. A group of experts working independently at first and then consensually used the interview transcripts to generate a 46-item questionnaire.

RESULTS

Analysis of questionnaires completed by 263 patients with hip or knee OA resulted in the exclusion of three items (two because of low reliability and one because of a low response rate). Principal component analysis revealed four factors: physical activity, mental health, social functioning, and social support. A pain dimension was individualized. Preliminary testing showed the reliability of the five dimensions to be satisfactory (intraclass correlation coefficients: 0.70-0.85), construct validity was adequate when correlated with the SF36 (Spearman correlation coefficients: 0.43-0.75), and discrimination was satisfactory. The osteoarthritis knee and hip quality of life questionnaire (OAKHQOL) consists of 43 items in five dimensions and three independent items.

CONCLUSION

The OAKHQOL is the first specific knee and hip OA quality of life instrument. Its development followed an a priori structured strategy to ensure content validity. It meets psychometric requirements for validity and reliability.