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Maarten Boers

Publications and source records attributed to Maarten Boers.

At least 19 recordsLinked to original sources
PubMed2006

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.

Health Status Indicators↗
PubMed2006

The rate of NSAID-induced endoscopic ulcers increases linearly but not exponentially with age: a pooled analysis of 12 randomised trials.

The risk of major ulcer complications on treatment with non-steroidal anti-inflammatory drugs (NSAIDs) is known to increase exponentially with age. However, in a pooled analysis of 12 trial arms, the incidence of endoscopic ulcers on treatment with NSAID was found to increase with age in a roughly linear fashion. Thus, it is concluded that increasing age is associated with both more frequent and more serious NSAID gastropathy.

Adolescent↗
PubMed2006

Does updating improve the methodological and reporting quality of systematic reviews?

BACKGROUND: Systematic reviews (SRs) must be of high quality. The purpose of our research was to compare the methodological and reporting quality of original versus updated Cochrane SRs to determine whether updating had improved these two quality dimensions. METHODS: We identified updated Cochrane SRs published in issue 4, 2002 of the Cochrane Library. We assessed the updated and original versions of the SRs using two instruments: the 10 item enhanced Overview Quality Assessment Questionnaire (OQAQ), and an 18-item reporting quality checklist and flow chart based upon the Quality of Reporting of Meta-analyses (QUOROM) statement. At least two reviewers extracted data and assessed quality. We calculated the percentage (with a 95% confidence interval) of 'yes' answers to each question. We calculated mean differences in percentage, 95% confidence intervals and p-values for each of the individual items and the overall methodological quality score of the updated and pre-updated versions using OQAQ. RESULTS: We assessed 53 SRs. There was no significant improvement in the global quality score of the OQAQ (mean difference 0.11 (-0.28; 0.70 p = 0.52)). Updated reviews showed a significant improvement of 18.9 (7.2; 30.6 p < .01) on the OQAQ item assessing whether the conclusions drawn by the author(s) were supported by the data and/or analysis presented in the SR. The QUOROM statement showed that the quality of reporting of Cochrane reviews improved in some areas with updating. Improvements were seen on the items relating to data sources reported in the abstract, with a significant difference of 17.0 (9.8; 28.7 p = 0.01), review methods, reported in the abstract 35 (24.1; 49.1 p = 0.00), searching methods 18.9 (9.7; 31.6 p = 0.01), and data abstraction 18.9 (11.7; 30.9 p = 0.00). CONCLUSION: The overall quality of Cochrane SRs is fair-to-good. Although reporting quality improved on certain individual items there was no overall improvement seen with updating and methodological quality remained unchanged. Further improvement of quality of reporting is possible. There is room for improvement of methodological quality as well. Authors updating reviews should address identified methodological or reporting weaknesses. We recommend to give full attention to both quality domains when updating SRs.

Bibliometrics↗
PubMed2006

Traditional versus up-front [18F] fluorodeoxyglucose-positron emission tomography staging of non-small-cell lung cancer: a Dutch cooperative randomized study.

PURPOSE: We investigated whether application of positron emission tomography (PET) immediately after first presentation might simplify staging while maintaining accuracy, as compared with traditional strategy in routine clinical setting. METHODS: At first presentation, patients with a provisional diagnosis of lung cancer without overt dissemination were randomly assigned to traditional work-up (TWU) according to international guidelines or early PET followed by histologic/cytologic verification of lesions, or imaging and follow-up. Patients with [18F] fluorodeoxyglucose (18FDG) -avid, noncentral tumors without suspicion of mediastinal or distant metastases on PET proceeded directly to thoracotomy. Follow-up in presumed benign lesions was at least 12 months. In patients treated with surgery or neoadjuvant therapy, the quality of staging was measured by comparing the clinical stage to the final stage (combination of peroperative staging and 6 months of follow-up). To investigate test substitution, we analyzed the number of (non)invasive tests to achieve clinical TNM staging, and its associated costs. RESULTS: Between 1999 and 2001, 465 patients (233 TWU, 232 PET) were enrolled at 22 hospitals. The mean (standard deviation) number of procedures to finalize staging was equal in the TWU arm and the PET arm: 7.9 (2.0) v 7.9 (1.9), P = .90, respectively. Mediastinoscopies occurred significantly less often in the PET arm. Agreement between clinical and final stage was good in both arms (kappa = .85 v .78; P = .07). Costs did not differ significantly. CONCLUSION: Up-front 18FDG-PET in patients with (suspected) lung cancer does not reduce the overall number of diagnostic test, but it maintains quality of TNM staging with the use of less invasive surgery.

Aged↗
PubMed2006

Rationale and design of The Delphi Trial--I(RCT)2: international randomized clinical trial of rheumatoid craniocervical treatment, an intervention-prognostic trial comparing 'early' surgery with conservative treatment [ISRCTN65076841].

BACKGROUND: Rheumatoid arthritis is a chronic inflammatory disease, which affects 1% of the population. Hands and feet are most commonly involved followed by the cervical spine. The spinal column consists of vertebrae stabilized by an intricate network of ligaments. Especially in the upper cervical spine, rheumatoid arthritis can cause degeneration of these ligaments, causing laxity, instability and subluxation of the vertebral bodies. Subsequent compression of the spinal cord and medulla oblongata can cause severe neurological deficits and even sudden death. Once neurological deficits occur, progression is inevitable although the rapidity of progression is highly variable. The first signs and symptoms are pain at the back of the head caused by compression of the major occipital nerve, followed by loss of strength of arms and legs. The severity of the subluxation can be observed with radiological investigations (MRI, CT) with a high sensitivity. The authors have sent a Delphi Questionnaire about the current treatment strategies of craniocervical involvement by rheumatoid arthritis to an international forum of expert rheumatologists and surgeons. The timing of surgery in patients with radiographic instability without evidence of neurological deficit is an area of considerable controversy. If signs and symptoms of myelopathy are present there is little chance of recovery to normal levels after surgery. DESIGN: In this international multicenter randomized clinical trial, early surgical atlantoaxial fixation in patients with rheumatoid arthritis and radiological abnormalities without neurological deficits will be compared with prolonged conservative treatment. The main research question is whether early surgery can prevent radiological and neurological progression. A cost-effectivity analysis will be performed. 250 patients are needed to answer the research question. DISCUSSION: Early surgery could prevent serious neurological deficits, but may have peri-operative morbidity and loss of rotation of the head and neck. The objective of this study is to identify the best timing of surgery for patients at risk for the development of neurological signs and symptoms.

Adolescent↗
PubMed2006

Posttraumatic stress in aging World War II survivors after a fireworks disaster: a controlled prospective study.

Little is known about the effects of cumulative trauma and whether traumatized individuals are more vulnerable. In 2000, a fireworks disaster created the possibility to examine this issue among World War II survivors who were part of an ongoing longitudinal study. Between 1998 and 2000 posttraumatic stress increased in disaster exposed respondents as opposed to the control group. War-related reexperiencing and avoidance also increased. The strongest increase occurred in disaster-exposed respondents who had low levels of wartime stress and a slight decrease occurred in those who had high wartime exposure. This unique controlled observation suggests that disasters do increase the levels of posttraumatic stress, and that reactivation of previous traumatic events generally occurs. However, the vulnerability hypothesis was not supported.

Aged↗
PubMed2005

Scope for improvement in the quality of reporting of systematic reviews. From the Cochrane Musculoskeletal Group.

OBJECTIVE: To assess the quality of reporting in Cochrane musculoskeletal systematic reviews (excluding back and injury reviews). METHODS: This study assessed all the Cochrane Musculoskeletal Group's systematic reviews from Issue 4, 2002, of the Cochrane Library Database of Systematic Reviews. Two reviewers independently extracted data and assessed quality. Two assessment tools were used, including an 18 item checklist and flow chart developed by the Quality of Reporting of Meta-analysis (QUOROM) consensus group, and a 10 item scale, the Oxman-Guyatt Overview Quality Assessment Questionnaire (OQAQ). One question on the latter scale (item 10) scores overall quality on a 7 point scale, with high scores indicating superior quality. Data were analyzed using univariate approaches. RESULTS: The 57 systematic reviews assessed were found to have good overall quality, with scores on individual items revealing only minor flaws. Documenting the flow of included and excluded studies and summarizing the results are 2 areas needing improvement in reporting. According to the Oxman-Guyatt scale the overall scientific quality of the Cochrane musculoskeletal reviews was good [mean 5.02 (95% CI 3.71-6.32)]. CONCLUSION: Our study found that the reporting quality of Cochrane musculoskeletal systematic reviews was generally good, although there was room for improvement. For example, it might be feasible to develop specific guidelines for reporting protocols. Certainly more work is needed in reporting search results, documentation of the flow of studies, identification of the type of studies, and summarization of the key findings.

Evidence-Based Medicine↗
PubMed2005

Development of a standardized method of assessment of radiographs and radiographic change in juvenile idiopathic arthritis: introduction of the Dijkstra composite score.

OBJECTIVE: To evaluate the sensitivity to change of a newly developed radiologic assessment tool, the Dijkstra score, and to develop a numeric composite score and progressor classification scheme to apply in juvenile idiopathic arthritis (JIA) trials. METHODS: A placebo-controlled trial of sulfasalazine (SSZ) in patients with oligoarticular- and polyarticular-onset JIA yielded the data for this study. Data were obtained from 418 sets of radiographs of the clinically involved and contralateral joints (at study entry and at 6 months' followup) from 66 JIA patients. The Dijkstra score assesses the presence or absence of swelling, osteopenia, joint space narrowing, growth abnormalities, subchondral bone cysts, erosions, and malalignment. These signs were combined in the Dijkstra composite score, to assess inflammation (DI), growth (DG), and damage (DD). Progression was defined as an increase in either the DG or the DD score. Scores were evaluated among all radiographs, a standard set of films (hand, foot, and knee), and per patient. All scores were used to explore differences between the 2 treatment groups. RESULTS: Over time, 58% of joints remained normal, 23% remained abnormal but stable, 14% showed an increase in signs, and 5% showed a decrease in signs. Of the 66 JIA patients, 12% had normal radiographic findings throughout followup, 27% showed abnormalities at some sites without change, and 61% showed change in at least 1 site. Changes in the DI, DG, and DD scores varied considerably per type of joint and occurred most frequently in joints of the standard set. DI and DG scores changed most often in the knees, while DD scores changed primarily in the hands and feet. The disease course in 8% of joints was classified as progressive. Films of SSZ-treated patients, versus the placebo group, showed less deterioration by the DD scores (P = 0.04), and the disease course was more often classified as nonprogressive in the SSZ group (P = 0.037). When progressors were defined as those who had at least one radiograph showing progression, significantly more placebo-treated patients were considered progressors (P = 0.046). CONCLUSION: In this trial data set, the Dijkstra composite score and the resulting progressor classification system are comprehensive and feasible tools that are sensitive to change and discriminate between clinical situations. They should now be tested by other investigators and in other data sets.

Antirheumatic Agents↗
PubMed2005

Direct medical costs of traumatic thoracolumbar spine fractures.

BACKGROUND: The costs and cost-effectiveness of treatment of thoracolumbar fractures are poorly known. METHODS: We estimated the costs of hospital care and outpatient visits for patients with traumatic thoracolumbar spine fractures. RESULTS: Stable fractures without neurological deficits were treated nonoperatively and the costs were EUR 5,100. Unstable fractures without neurological deficits were treated either nonoperatively, with an average of 29 hospitalization days and average cost of EUR 12,500 (86% of which represented hospitalization costs), or operatively with 24 hospitalization days and average cost of EUR 19,700 (48% of which represented hospitalization costs and 42% surgery costs). Unstable fractures with neurological deficits were usually operated (average costs EUR 31,900). INTERPRETATION: For all patients, the costs of hospitalization days were the main cost driver. Although the length of stay for patients with unstable fractures and without neurological deficit who were treated operatively was shorter than for patients treated nonoperatively, the total costs were higher due to the additional costs of surgery. Surgical treatment must therefore be shown to give a better outcome in order to outweigh the costs. Future research should focus on the cost-effectiveness of operative and nonoperative treatment of patients with unstable vertebral fractures who have no neurological deficits, and take indirect costs and quality of life into account.

Adolescent↗
PubMed2005

Outcome measures for clinical research in sepsis: a report of the 2nd Cambridge Colloquium of the International Sepsis Forum.

BACKGROUND AND OBJECTIVES: Sepsis is the leading cause of morbidity and mortality for patients admitted to an intensive care unit. The evaluation of new therapies has been hampered by the underdevelopment of outcome measures used to detect biological activity and patient-centered benefit in a complex and highly heterogeneous patient population. We sought to evaluate existing approaches and to draw on insights from other disciplines to propose a comprehensive approach to outcome evaluation in sepsis clinical trials. METHODS: An expert colloquium organized by the International Sepsis Forum brought together sepsis researchers, clinical epidemiologists, and experts in the development and implementation of outcome measures in rheumatology, neurology, and oncology. RESULTS: The translation of an evolving understanding of the biology of sepsis into effective new therapies for critically ill patients requires a reevaluation of the end points used to determine response to intervention. These represent a continuum that measures biological activity against the target at one end and sustained improvement in survival or quality of life at the other. Early phase research should determine whether an intervention works in vivo, using measures that are responsive and informative to provide proof of principle, to aid in selecting optimal patient populations for study, and to gain insights into optimal dose and duration of therapy. After in vivo biology has been demonstrated and the possibility of efficacy inferred by plausible improvements in surrogate physiologic measures, definitive studies should seek robust evidence of benefit using end points that measure important, patient-centered benefit, including intermediate and longer term survival and health-related quality of life. Nonmortal measures of benefit assume particular importance for populations, such as children, whose mortality risk is low, or who have significant rates of comorbidities that independently limit survival. Composite measures that integrate morbidity and mortality effects may provide the most meaningful information about therapeutic efficacy. CONCLUSIONS: The development of explicit, hypothesis-driven, and iterative approaches to outcome measure development, patterned on approaches used in the fields of rheumatology and oncology, may improve the conduct of clinical studies in the critically ill.

Clinical Trials as Topic↗
PubMed2005

Minimal disease activity for rheumatoid arthritis: a preliminary definition.

Agreement on response criteria in rheumatoid arthritis (RA) has allowed better standardization and interpretation of clinical trial reports. With recent advances in therapy, the proportion of patients achieving a satisfactory state of minimal disease activity (MDA) is becoming a more important measure with which to compare different treatment strategies. The threshold for MDA is between high disease activity and remission and, by definition, anyone in remission will also be in MDA. True remission is still rare in RA; in addition, the American College of Rheumatology definition is difficult to apply in the context of trials. Participants at OMERACT 6 in 2002 agreed on a conceptual definition of minimal disease activity (MDA): "that state of disease activity deemed a useful target of treatment by both the patient and the physician, given current treatment possibilities and limitations." To prepare for a preliminary operational definition of MDA for use in clinical trials, we asked rheumatologists to assess 60 patient profiles describing real RA patients seen in routine clinical practice. Based on their responses, several candidate definitions for MDA were designed and discussed at the OMERACT 7 in 2004. Feedback from participants and additional on-site analyses in a cross-sectional database allowed the formulation of 2 preliminary, equivalent definitions of MDA: one based on the Disease Activity Score 28 (DAS28) index, and one based on meeting cutpoints in 5 out the 7 WHO/ILAR core set measures. Researchers applying these definitions first need to choose whether to use the DAS28 or the core set definition, because although each selects a similar proportion in a population, these are not always the same patients. In both MDA definitions, an initial decision node places all patients in MDA who have a tender joint count of 0 and a swollen joint count of 0, and an erythrocyte sedimentation rate (ESR) no greater than 10 mm. If this condition is not met: * The DAS28 definition places patients in MDA when DAS28 < or = 2.85; * The core set definition places patients in MDA when they meet 5 of 7 criteria: (1) Pain (0-10) < or = 2; (2) Swollen joint count (0-28) < or = 1; (3) Tender joint count (0-28) < or = 1; (4) Health Assessment Questionnaire (HAQ, 0-3) < or = 0.5; (5) Physician global assessment of disease activity (0-10) < or = 1.5; (6) Patient global assessment of disease activity (0-10) < or = 2; (7) ESR < or = 20. This set of 2 definitions gained approval of 73% of the attendees. These (and other) definitions will now be subject to further validation in other databases.

Arthritis, Rheumatoid↗
PubMed2005

Standardized assessment of adverse events in rheumatology clinical trials: summary of the OMERACT 7 drug safety module update.

A presentation, demonstration, and discussion of recently developed adverse event instruments were the topics for the OMERACT 7 Drug Safety Module. The module began with a plenary introducing the needs and challenges of adverse event ascertainment. It was followed by a review of module work from previous OMERACT meetings on a prototype coding instrument (Rheumatology Common Toxicity Criteria), then a brief description of the process behind the recently developed patient self-report and investigator report adverse event instruments. These current instruments are designed for use in controlled trials although they could be used in other settings. The instruments rely primarily on patient self-reporting using a checklist, which the investigator then folds into a parallel structured but more medically sophisticated instrument. In pilot testing, this innovative dual-use system has shown reliability and acceptability, while preserving validity. A "stakeholder panel" of representatives from 8 sectors followed--patient, nurse investigator, regulator, clinician scientist, industry, OMERACT, global public health/WHO, and Cochrane Collaboration--for their perspectives on the needs, challenges, and potential ways forward for adverse event ascertainment and reporting in clinical trials. At the breakout session small focus groups participated in hands-on interactive testing of one of 3 versions of the instruments, which differ in degree of comprehensiveness. Each focus group had a participatory patient with rheumatoid arthritis. At a second plenary there was group feedback by rapporteurs and presentation of results from pilot studies of iterative testing of validity, reliability, and feasibility of the instruments. During plenary discussion a frequent suggestion for improvement was to refine the process so that event ascertainment could be done entirely using the patient instrument with minimal input from the investigator at the visit, if patient-investigator agreement was high. Most found the patient checklist attractive, particularly if the patient instrument was shown to be reliable and valid. Finally, a future research agenda was discussed.

Adverse Drug Reaction Reporting Systems↗
PubMed2005

Current status of outcome measures in vasculitis: focus on Wegener's granulomatosis and microscopic polyangiitis. Report from OMERACT 7.

The complexity of assessing disease activity, disease status, and damage in the vasculitides reflects the multisystemic pathologic manifestations of these often chronic illnesses. Major progress has been made in the past decade in the development of validated and widely accepted outcome measures for use in clinical trials. Over time, these tools have been regularly revised, expanded, and supplemented with new measures of disease prognosis and damage. As a result clinical research in this area has become increasingly complex. This article critically reviews the current status of tools for assessing disease activity and damage in "ANCA-associated" vasculitides (Wegener's granulomatosis and microscopic polyangiitis), summarizes the current level of validation of each measure, addresses central problems and controversies to be considered during development of new vasculitis assessment tools, and proposes a series of research agendas for consideration by the vasculitis research community.

Clinical Trials as Topic↗
PubMed2004

Progression of radiologic damage in patients with rheumatoid arthritis in clinical remission.

OBJECTIVE: To assess whether radiologic progression occurs during clinical remission in patients with rheumatoid arthritis (RA). METHODS: One hundred eighty-seven patients with RA in clinical remission were followed up clinically and radiologically for 2 years. Clinical remission was defined according to a modification of the American College of Rheumatology criteria (i.e., the criterion of fatigue was omitted, and patients had to fulfill 4 of the 5 remaining criteria). Radiologic joint damage was assessed by the Sharp/van der Heijde method. RESULTS: After 2 years of followup, remission persisted in 52% of patients. The median radiologic score for the total group of patients increased from 21 (interquartile range [IQR] 5, 65) at the time of entry to 25 (IQR 7, 72) after 2 years (P < 0.001). The median score for radiologic progression between baseline and 2 years was 0.5 (IQR 0, 2.5). Among patients with an exacerbation of RA (n = 86), the median score for progression over 2 years was 1.0 (IQR 0, 4.5) (P < 0.001), and in patients with a persistent remission (n = 93) it was 0 (IQR -0.5, 2.0) (P < 0.001). Clinically relevant progression of damage was more frequent in patients with exacerbation (23%) than in those with persistent remission (7%) (P = 0.001). However, in 15% of patients with persistent remission, an erosion developed in a previously unaffected joint. In the logistic regression analysis, the area under the curve of the Disease Activity Score, a continuous measure, was related to the chance of radiologic progression, regardless of the absolute disease activity level. Results were similar when other definitions of remission were used. CONCLUSION: Although rare, clinically relevant progression of joint damage does occur in patients with RA in prolonged remission. This suggests the need for markers that predict progression during periods of low disease activity and for drugs that prevent damage that is independent of disease activity.

Aged↗