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Biomedical subjects

M Boers

Publications and source records attributed to M Boers.

At least 55 records · Page 3Linked to original sources
PubMed2001

Bone turnover, joint damage and bone mineral density in early rheumatoid arthritis treated with combination therapy including high-dose prednisolone.

OBJECTIVES: Exploration of bone metabolism changes at different levels of disease activity, both with and without oral corticosteroid therapy, and prediction of changes in joint damage and bone density from the observed changes in markers of bone turnover. METHODS: Data analysis from a randomized clinical trial with 155 rheumatoid arthritis (RA) patients; median age 50 yr, early and active disease (diagnosis < 2 yr); one group treated with a combination of sulphasalazine (SSZ; 2000 mg/day), methotrexate (MTX; 7.5 mg/week) and prednisolone (initially 60 mg/day, tapered in six weekly steps to 7.5 mg/day), the other group with SSZ alone. Prednisolone and MTX were tapered and stopped after weeks 28 and 40, respectively, while SSZ was continued. Urine and serum samples were collected at baseline and weeks 16, 28, 40 and 56. Measurements of urinary pyridinoline (PYD) and deoxypyridinoline (DPD) and serum alkaline phosphatase (tAP) and osteocalcin (OC) were performed, as well as standard clinimetry and bone densitometry. RESULTS: Over time and in both treatment groups, bone formation and bone resorption markers showed a pattern similar to erythrocyte sedimentation rate (ESR): a significant decrease compared with baseline and a larger decrease with combined treatment at weeks 16 and 28. PYD excretion, tAP, OC, and joint damage scores were significantly lower in the combined treatment group. Changes in bone density (of spine and hips) did not significantly differ between treatment groups. Mainly cumulative ESR explained progression of joint damage. CONCLUSIONS: Prednisolone and disease-modifying anti-rheumatic drug therapy in patients with early and active RA are both independently associated with decreased levels of urinary excretion of bone collagen resorption markers PYD and DPD. Markers of bone formation and resorption closely followed changes in ESR in both treatment groups. Reduced bone resorption together with reduced bone formation-initially at a somewhat faster pace-resulted in less bone turnover and explain the observed (non-significant and partially reversible) extra bone loss in the lumbar spine associated with prednisolone (combined treatment).

Adult↗
PubMed2001

Diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography in the follow-up of papillary or follicular thyroid cancer.

Positron emission tomography with 18F-fluorodeoxyglucose is a relatively new nuclear imaging technique in oncology. We conducted a systematic review to determine the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography in patients suspected of recurrent papillary or follicular thyroid carcinoma. Two reviewers independently selected, extracted, and assessed data from relevant literature found in computerized databases and by reference tracking. Prospective and retrospective studies with 10 human subjects, or more, that evaluated the accuracy of ring positron emission tomography, using 18F-fluorodeoxyglucose in follicular and papillary thyroid cancer, were included. Studies on 18F-fluorodeoxyglucose imaging using gamma cameras, reviews, case reports, editorials, letters, and comments were excluded. The methodological quality was assessed by applying the criteria for diagnostic tests recommended by the Cochrane Methods Group on Screening and Diagnostic Tests. A rating system was used for qualitative analysis consisting of four levels of evidence (1 = highest level; 4 = lowest level). Fourteen studies met the inclusion criteria. All studies claimed a positive role for positron emission tomography but, at evidence levels 3 or 4, precluding quantitative analysis. Methodological problems included poor validity of reference tests and a lack of blinding of test performance and interpretation. The reviewed material was heterogeneous with respect to patient variation and validation methodology. The most consistent data were found on the ability of 18F-fluorodeoxyglucose positron emission tomography to provide an anatomical substrate in patients with elevated serum Tg and negative iodine-131 scans. In conclusion, the results seem to support the potential of 18F-fluorodeoxyglucose positron emission tomography to identify and localize foci of recurrent cancer in the latter patient subset. However, implementation of positron emission tomography in a routine diagnostic algorithm requires additional evidence.

Adenocarcinoma, Follicular↗
PubMed2001

Looking for important change/differences in studies of responsiveness. OMERACT MCID Working Group. Outcome Measures in Rheumatology. Minimal Clinically Important Difference.

The purpose of this paper is to describe a classification system for studies of responsiveness that was designed to help organize these studies, and identify those with the potential to provide information on minimal clinically important difference (MCID). We developed a 3 dimensional cube into which studies of responsiveness can be categorized based on their evaluation of 3 attributes: 1. individual or group setting; 2. which scores are contrasted; and 3. the type of change or difference being assessed. We present and discuss examples of studies that fit into categories in the classification cube. This classification system helps to focus attention on whether the literature is able to provide information on the specific type of change a person is interested in. It reinforces that the ability of an instrument to detect a certain category of discrimination within the cube does not mean it will necessarily be responsive to another category. The cube has been shown here as a means to separate out studies that address important change. These studies can then be examined as the source of information on MCID.

Clinical Trials as Topic↗
PubMed2001

Minimal clinically important differences: review of methods.

Determining a minimal clinically important difference to be detected in a clinical trial is a critical methodological step in the design of a study. In this review, the different methods that have been used in detecting important changes or differences are considered and categorized according to a classification system consisting of which groups are contrasted, the setting of the results, and the type of change of difference being quantified. It was found that most methods and procedures for deriving minimal clinically important differences considered important changes from the viewpoint of a group of patients. Development of methods that focus on individuals should be a goal of the future.

Clinical Trials as Topic↗
PubMed2001

High dose chemotherapy followed by autologous peripheral blood stem cell transplantation or conventional pharmacological treatment for refractory rheumatoid arthritis? A Markov decision analysis.

OBJECTIVE: To evaluate the effect of high dose chemotherapy (HDC) followed by autologous hematopoietic stem cell transplantation (ASCT) in comparison to conventional pharmacological therapy in the treatment of patients with refractory, progressively erosive rheumatoid arthritis (RA). METHODS: Decision analysis using a Markov model with a 5.5 year time horizon. Probabilities of transition towards 5 different health states, ranging from 70% improvement to death, were derived from published case reports, patient series, and expert panels. Quality of life (QOL) estimates were obtained from 2 RA clinical trials. Patients were hypothetical cohorts of 50-year-old female patients with progressively erosive, active RA, who failed treatment with methotrexate, combination therapy, and tumor necrosis factor blocking agents. Interventions were HDC + ASCT versus conventional pharmacological treatment with a (combination) therapy of disease modifying antirheumatic drugs. As main outcome measures, we included the number of quality adjusted life years (QALY) after HDC + ASCT compared to conventional therapy. Sensitivity analysis was performed to investigate the influence of treatment related mortality (TRM) and the influence of QOL during HDC + ASCT, and to assess the minimal desired effectiveness of HDC + ASCT for a given TRM of 1% and 10%. RESULTS: HDC + ASCT and conventional pharmacological treatment were equally effective in the base-case analysis (3.48 vs 3.46 QALY). A TRM of less than 3.3% favored HDC + ASCT as the preferred treatment. The analysis showed that when TRM was set at 1%, a relatively short period of efficacy was sufficient to remain the preferred strategy, whereas a TRM of 10% would require a sustained response for several years. CONCLUSION: This model predicted equally favorable effects of HDC + ASCT and conventional therapy in the treatment of refractory RA in the base-case. The minor differences in terms of QALY seem to indicate that clinical decision making should be guided by patient preferences. However, better clinical efficacy might be achieved by adaptation of the treatment regimen of HDC + ASCT and patient selection. The model supports the need for randomized clinical trials and may contribute to an optimal study design.

Antirheumatic Agents↗
PubMed2001

Recent rheumatoid arthritis clinical trials using radiographic endpoints--updated research agenda.

Recent randomized controlled trials of traditional and newly developed therapies provide evidence that we have interventions that potentially slow or prevent structural damage in active rheumatoid arthritis, as measured using radiography. These trials also provide a unique opportunity for exploratory data analysis to generate hypotheses apropos the pathogenesis and determinants of radiographic progression and functional disability; they also facilitate further study of the methodological issues regarding imaging measurement.

Arthritis, Rheumatoid↗
PubMed2001

Reliability of measures of disease activity and disease damage in rheumatoid arthritis: implications for smallest detectable difference, minimal clinically important difference, and analysis of treatment effects in randomized controlled trials.

We evaluate measurement properties of common rheumatoid arthritis (RA) assessments. Included are a comprehensive literature review and new data on the reliability and smallest detectable difference (SDD) for different classes of these measures. We found that certain common measures such as joint counts, pain, and patient global all had poor reliability and showed large SDD compared to multi-item measures of physical/psychological function or compared to radiographic measures. We discuss the implications of these findings on the use of composite endpoints such as the ACR20 or the EULAR responder index in RA clinical trials, particularly the introduction of misclassification bias that arises from differential measurement error. Finally, we consider generically how the concept of the SDD might or might not relate to the concept of the minimal clinically important difference.

Aged↗
PubMed2001

Minimal clinically important difference in radiological progression of joint damage over 1 year in rheumatoid arthritis: preliminary results of a validation study with clinical experts.

To determine the minimal clinically important difference (MCID) between hand and foot films with a 1 year interval assessed with the Sharp/van der Heijde or Larsen/Scott scoring method. Progression scores of the 2 methods were compared with the opinion of an international expert panel on clinical relevance of radiological joint damage in 4 predefined clinical settings. The expert panel consisted of 3 rheumatologists, who evaluated 46 pairs of hand and foot films, taken with 1 year intervals, of patients with early rheumatoid arthritis. Receiver operating characteristics curves analyzed the accuracy of different threshold values (progression scores) of the 2 scoring methods to detect the presence or absence of clinically important difference, as defined by the expert panel as external criterion. The threshold value with the highest accuracy was subsequently chosen as the score representing the MCID. Five Sharp/van der Heijde units and 2 Larsen/Scott units were the best cutoffs. The accompanying sensitivities ranged from 77% to 100% for the Sharp/van der Heijde method and from 73% to 84% for the Larsen/Scott method for the 4 clinical settings. The specificities were between 78% and 84% for the Sharp/van der Heijde method and between 74% and 94% for the Larsen/Scott method. The smallest progression score that can be detected apart from interobserver measurement error, the smallest detectable difference (SDD), was equal to or larger than the calculated MCID, 5 Sharp/van der Heijde units and 6 Larsen/Scott units in our study, if the mean progression scores of the same 2 observers were used. The SDD is a conservative estimate of the MCID; our panel rated progression at or below this level as clinically significant.

Arthritis, Rheumatoid↗
PubMed2001

Robustness and generalizability of smallest detectable difference in radiological progression.

The smallest detectable difference (SDD) reflects that component of a measure statistically attributable to error from the measurement process itself. As such it is an irreducible component of the inherent variability in measurements in clinical trials and will affect their design, whether randomized or observational. Even though the application of the SDD concept to assaying radiographs in rheumatoid arthritis is relatively new and not well understood, systematic work on the influences of radiographic SDD can be done. This report describes the effects of a number of clinical aspects of the disease and operational aspects of trials on the values of the SDD of radiographic progression data. We show that if conditions affecting SDD are known and kept constant across datasets, the SDD of radiological progression from one study may be generalizable to other studies. However, if any one condition varies, the SDD is distinctly unrobust and cannot be generalized to other studies.

Arthritis, Rheumatoid↗
PubMed2001

Minimal clinically important difference in plain films in RA: group discussions, conclusions, and recommendations. OMERACT Imaging Task Force.

Analysis of progression of structural damage on an individual patient level in randomized controlled trials provides extra information in addition to the analysis on a group level. A cutoff level is required to define which patients show progression and which patients do not. The objective of the mimimal clinically important difference (MCID) module for plain films was to elaborate the various concepts to determine a MCID for plain films, and if possible, to define a MCID for specific scoring methods. The module comprised preconference reading material, a plenary session, small group discussions, and a plenary report of the group sessions, combined with interactive voting. The following conclusions and recommendations were made: the smallest detectable difference (SDD) beyond measurement error is a good starting point to define MCID; SDD is study-specific; SDD should be reported for all radiographic endpoints used in a trial as a quality control; the expert panel approach is a reasonable method to define MCID, but defined in this way MCID may be smaller than current SDD; more research is needed to validate expert panel based MCID in different datasets and with different experts; a predictive, data driven MCID is the ultimate goal, but is not yet available; the SDD can be used as a proxy for MCID until a data driven MCID is available; analysis at the group level (comparison of means or medians) should remain primary in studies that include progression of joint damage as outcome measure; the proportion of patients showing more progression than the SDD is a secondary outcome measure.

Arthritis, Rheumatoid↗
PubMed2001

Patient based method of assessing adverse events in clinical trials in rheumatology: the revised Stanford Toxicity Index.

We describe the progress towards developing a patient rated toxicity index that meets all of the patient-important attributes defined by the OMERACT Drug Safety Working Party. These attributes are frequency, severity, importance to patient, importance to the clinician, impact on economics, impact on activities, and integration of adverse effects with benefits. The Stanford Toxicity Index (STI) has been revised to collect all attributes with the exception of impact on activities. However, since the STI is a part of the Health Assessment Questionnaire (HAQ), impact on activities is collected by the HAQ. In particular, a new question asks patients to rate overall satisfaction, taking into consideration both benefits and adverse effects. The next step in the development of this tool is to ensure that the STI meets the OMERACT filter of truth, discrimination, and feasibility. Although truth and feasibility have been confirmed by comparisons within the ARAMIS database, discrimination needs to be assessed in clinical trials.

Adverse Drug Reaction Reporting Systems↗
PubMed2000

[Roaming through methodology. XXV. Outcome measures, surrogate outcomes, and intermediate measures].

Clinical medicine is aimed at decreasing the current or future burden of disease. Disease outcome is best expressed as burden of disease or change thereof, and as such the only true 'outcome measure' in clinical research. However, outcome research is expensive in costs and time expenditure, and sometimes impossible. Therefore study results are often expressed in intermediate measures. These measures tell us something about the disease process and the pathophysiological consequences of the disease and should have a relation with outcome. If this relation is strong, the measure is called 'surrogate outcome'. Intermediate measures and surrogate outcomes have advantages and disadvantages. The reader of clinical trial results first has to decide whether the answer to the study question is relevant in his personal situation. If so, the applicability of a measure can be simply appraised by answering 3 questions: 'Is the measure truthful (relevant, unbiased)?'; 'Does it discriminate between situations that are of interest?'; 'Is the measure feasible in my setting?'

Clinical Trials as Topic↗
PubMed2000

Balneotherapy for rheumatoid arthritis and osteoarthritis.

BACKGROUND: Balneotherapy (hydrotherapy or spa therapy) for patients with arthritis is one of the oldest forms of therapy. One of the aims of balneotherapy is to soothe the pain and as a consequence to relieve patients' suffering and make them feel well. OBJECTIVES: To perform a systematic review to assess the effects of balneotherapy for rheumatoid arthritis and osteoarthritis. SEARCH STRATEGY: Using the Cochrane search strategy, studies were found by screening: 1) The Medline CD-ROM database from 1966 to June 1999 and 2) the database from the Cochrane Field 'Rehabilitation and Related Therapies', which contains also studies published in journals not covered by Medline. Also, 3) reference checking and 4) personal communications with authors was carried out to retrieve eligible studies. To perform an adequate assessment of the methodological quality the languages of the publications had to be: Dutch, English, French or German. Date of the most recent literature search: June, 1999 SELECTION CRITERIA: Studies were eligible if they were randomized controlled trials (RCT) comparing balneotherapy with any intervention or with no intervention. Patients included had rheumatoid arthritis (RA), osteoarthritis (OA) or some other form of arthritis. Trials incorporating patients with definite or classical rheumatoid arthritis (RA) as defined by the American Rheumatism Association Criteria (ARA) (Ropes 1958) (these criteria have changed over time) or by the criteria of Steinbrocker (1949) were regarded as a separate group. At least one of the WHO/ILAR core set of endpoints for RA clinical trials had to be the main outcome measures. DATA COLLECTION AND ANALYSIS: A criteria list used to assess the methodological quality was the one developed at the Department of Epidemiology at the Maastricht University, called "the Maastricht list". The quality scores and data abstraction of the studies were carried out independently by two reviewers (HdV, RdB). Disagreements were solved by consensus. MAIN RESULTS: Ten trials with 607 patients were included in this review. Most trials reported positive findings, but were methodologically flawed to some extent. A 'quality of life' outcome was reported by two trials. Just one of the randomized trials mentioned an intention-to-treat analysis and only three performed a comparison of effects between groups. Pooling of the data was not performed, because of heterogeneity of the studies, multiple outcome measurements, and, apart from two studies, the overall data presentation was too scarce to enable pooling of the data. REVIEWER'S CONCLUSIONS: One cannot ignore the positive findings reported in most trials. However the scientific evidence is weak because of the poor methodological quality, the absence of an adequate statistical analysis, and the absence, for the patient, of most essential outcome measures (pain, quality of life), Therefore, the noted "positive findings" should be viewed with caution. Because of the methodological flaws an answer about the efficacy of balneotherapy cannot be provided at this time. Flaws found in the reviewed studies could be avoided in future trials.

Arthritis, Rheumatoid↗