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Biomedical subjects

S van der Linden

Publications and source records attributed to S van der Linden.

At least 19 recordsLinked to original sources
PubMed1998

Chronicity of back problems during working life.

STUDY DESIGN: A follow-up study of a cohort of 444 patients aged 16 to 59 years who consulted with their general practitioners (GPs) in 1987-1988 for an incident episode of back pain. OBJECTIVES: To determine the proportion of patients with back pain in whom chronic back problems develop after a follow-up of 7 years, to compare health outcomes and labor force participation of patients with and without chronic back problems and to identify determinants of chronicity. SUMMARY OF BACKGROUND DATA: The incidence and prevalence of back pain are very high. A large proportion of the costs related to medical consumption, absence from work, and disability are probably caused by chronic back problems. It is unknown what proportion of back problems become chronic, especially after a long follow-up period, and which factors can predict chronicity. METHODS: Data on the course of the symptoms and medical consumption from the period between 1987-1988 and 1991 were gathered retrospectively. Data on several health outcomes, including LFP, and data on some work characteristics were collected prospectively in 1991. A more extensive data set on health outcomes including psychologic status and working situation was collected in 1994. RESULTS: Chronic back problems developed in 28% of the patients. These patients reported more pain, higher levels of medical resource consumption, worse health outcomes, and lower labor force participation. Episodes of back pain before 1987-1988, severe pain in 1991, and disability score in 1991 were positively associated with chronicity in 1994, difficulties with job performance in 1991, and frequent stooping in the subgroup of patients who held a paying job in the follow-up period. CONCLUSIONS: Even after a follow-up of 7 years, the proportion of people with chronic back problems was high. The consequences for quality of life, labor force participation, and consumption of medical resources are clear. Further research is necessary to examine determinants and ways to prevent chronicity.

Adolescent↗
PubMed1998

Comparison of the electrophysiology and morphology of layers III and II neurons of the rat medial entorhinal cortex in vitro.

The basic membrane characteristics of neurons in layers II and III of the medial entorhinal cortex (MEA) were recorded using the intracellular current clamp technique in in vitro slices of the rat brain. Two types of cells were distinguished according to the presence of a time-dependent inward rectification (SAG current) with hyperpolarizing current pulses. The cells in which this inward rectification was not observed (No-SAG cells) had a larger input resistance, a more negative resting membrane potential and a more depolarized firing threshold. They more often displayed a strongly adapting firing pattern, and their action potentials had a slower decay rate and lacked a depolarizing afterpotential, compared with the SAG cells. SAG cells typically had a prominent rebound depolarization at the end of a hyperpolarizing current and membrane potential oscillations (7 Hz) upon subthreshold depolarizations. Cs+ blocked the time-dependent inward rectification. The rebound depolarization persisted, even in the presence of tetrodotoxin. Biocytin labelling showed that layer III consisted mainly of pyramidal-shaped cells. Most layer III cells were of the No-SAG type. All cells in layer II, stellate and pyramidal cells, were classified as SAG cells. We conclude that the cells in MEA layers II and III display different electroresponsiveness, but that this appears to be more related to the layer where they are located than to a specific morphology. As layer III consisted mainly of cells of the No-SAG type, we suggest that layer III cells are less excitable than the SAG type layer II cells.

Animals↗
PubMed1998

Cost-effectiveness and cost-utility of combination therapy in early rheumatoid arthritis: randomized comparison of combined step-down prednisolone, methotrexate and sulphasalazine with sulphasalazine alone. COBRA Trial Group. Combinatietherapie Bij Reumatoïde Artritis.

OBJECTIVE: Assessment of the cost-effectiveness and cost-utility of early intervention in rheumatoid arthritis (RA) patients, with combined step-down prednisolone, methotrexate and sulphasalazine, compared to sulphasalazine alone. METHODS: Multicentre 56 week randomized double-blind trial with full economic analysis of direct costs and utility analysis with rating scale and standard gamble measurement techniques. RESULTS: The combined-treatment group included 76 patients and the sulphasalazine group 78 patients. The mean total costs per patient in the first 56 weeks of follow-up were $5519 for combined treatment and $6511 for treatment with sulphasalazine alone (P = 0.37). Out-patient care, in-patient care and non-health care each contributed about one-third to the total costs. The combined-treatment group appeared to generate savings in the length of hospital stay for RA, non-protocol drugs and costs of home help, but comparisons were not statistically significant. Protocol drugs and monitoring were slightly more expensive in the combined-treatment group. Clinical, radiographic and functional outcomes significantly favoured combined treatment at week 28 (radiography also at week 56). Utility scores also favoured combined treatment. CONCLUSION: Combined treatment is cost-effective due to enhanced efficacy at lower or equal direct costs.

Adult↗
PubMed1997

[Combination therapy in early rheumatoid arthritis: the COBRA study].

The scheme 'Combination therapy in rheumatoid arthritis' (COBRA) in early rheumatoid arthritis (RA) involves administration of not only sulfasalazine but also prednisolone and methotrexate during the first six months. The trial showed that the COBRA scheme over a period of 1.5 years was superior to sulfasalazine alone: less disease activity in the major part of the year of treatment, less articular damage on radiographs, fewer side effects and equal or reduced costs. An 'aggressive' treatment in patients with early RA is indicated, with (re)assessment of the use of corticosteroids.

Anti-Inflammatory Agents↗
PubMed1997

Randomised comparison of combined step-down prednisolone, methotrexate and sulphasalazine with sulphasalazine alone in early rheumatoid arthritis.

BACKGROUND: The value of intensive combination therapy in early rheumatoid arthritis is unproven. In a multicentre, double-blind, randomised trial (COBRA), we compared the combination of sulphasalazine (2 g/day), methotrexate (7.5 mg/week), and prednisolone (initially 60 mg/day, tapered in 6 weekly steps to 7.5 mg/day) with sulphasalazine alone. METHODS: 155 patients with early rheumatoid arthritis (median duration 4 months) were randomly assigned combined treatment (76) or sulphasalazine alone (79). Prednisolone and methotrexate were tapered and stopped after 28 and 40 weeks, respectively. The main outcomes were the pooled index (a weighted change score of five disease activity measures) and the Sharp/Van der Heijde radiographic damage score in hands and feet. Independent health-care professionals assessed the main outcomes without knowledge of treatment allocation. FINDINGS: At week 28, the mean pooled index was 1.4 (95% CI 1.2-1.6) in the combined treatment group and 0.8 (0.6-1.0) in the sulphasalazine group (p < 0.0001). At this time, 55 (72%) and 39 (49%) patients, respectively, were improved according to American College of Rheumatology criteria. The clinical difference between the groups decreased and was no longer significant after prednisolone was stopped, and there were no further changes after methotrexate was stopped. At 28 weeks, the radiographic damage score had increased by a median of 1 (range 0-28) in the combined-therapy group and 4 (0-44) in the sulphasalazine group (p < 0.0001). The increases at week 56 (2 [0-43] vs 6 [0-54], p = 0.004), and at week 80 (4 [0-80] vs 12 [0-72], p = 0.01) were also significant. Further analysis suggests that combined therapy immediately suppressed damage progression, whereas sulphasalazine did so less effectively and with a lag of 6 to 12 months. There were fewer withdrawals in the combined therapy than the sulphasalazine group (6 [8%] vs 23 [29%]), and they occurred later. INTERPRETATION: This combined-therapy regimen offers additional disease control over and above that of sulphasalazine alone that persists for up to a year after corticosteroids are stopped. Although confirmatory studies and long-term follow-up are needed, this approach may prove useful in the treatment of early rheumatoid arthritis.

Adult↗
PubMed1997

Facilitated analysis of data on drug regimen compliance.

Drug actions depend on dose and intervals between doses, in ways that are drug-specific and sometimes complex, complicating the use of drug dosing histories as an explanatory variable in the analysis of clinical trials. We describe a spread-sheet method for conveniently displaying patients' drug dosing histories, to facilitate identification of dosing correlates of clinically important events.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Preliminary core sets for endpoints in ankylosing spondylitis. Assessments in Ankylosing Spondylitis Working Group.

An international working group was formed to select core sets to be used as endpoints in clinical trials in ankylosing spondylitis (AS). The results of the first steps of the selection of these core sets are described. The definition of the settings for which the core set will be intended are defined. The methods used to select the core sets were a combination of literature search, nominal group discussions, and plenary discussions. The following settings were defined: disease controlling antirheumatic therapy (DC-ART), symptom modifying antirheumatic drugs (SMARD)/physical therapy, and clinical record keeping. Over 110 variables used as endpoints in AS were found in the literature. The preliminary core set for DC-ART consists of physical function, pain, spinal mobility, patient global assessment, peripheral joints/entheses, x-ray spine. The selected core set for SMARD/physical therapy includes physical function, pain, spinal mobility, spinal stiffness, and patient global assessment. The core set for clinical record keeping includes all measures of the SMARD/physical therapy core set completed by peripheral joints/entheses, and acute phase reactants. Three preliminary core sets for AS have been defined. Further research will be performed to select specific measures for all domains.

Antirheumatic Agents↗
PubMed1996

[Various opinions of family physicians and rheumatologists about the management of patients with rheumatoid arthritis].

OBJECTIVE: To make an inventory of the opinions about professional duties and of the cooperation of general practitioners (GPs) and rheumatologists in the care of patients with rheumatoid arthritis (RA), after the publication of the standard 'Rheumatoid arthritis' issued by the Dutch College of General Practitioners in 1994. DESIGN: Descriptive. SETTING: Maastricht University, the Netherlands. METHOD: Information was collected by means of a written questionnaire submitted to a random sample of 500 GPs and all 148 (assistant) rheumatologists in the Netherlands, and by means of focus group interviews with GPs, rheumatologists and RA patients. This information focused on the opinion of both groups of professionals on their professional duties in diagnosis and management of RA, existing models of cooperation, the satisfaction with mutual consultations, experienced problems and possibilities to improve cooperation. RESULTS: Substantial differences existed between both groups of professionals in their views on the duties of the GP and the rheumatologist respectively, in the care of RA patients. GPs tended to an expectative policy in cases of suspected or even diagnosed RA, whereas rheumatologists preferred early referral. Hardly any cooperation model was found with agreements committed to paper on the mutual duties regarding RA patients. CONCLUSION: Inadequate mutual contacts and inadequate insight of both parties into each other's abilities appeared to be major problems impeding improvement of the mutual communication. Both groups recognized the need to improve the mutual cooperation.

Adult↗
PubMed1996

The social network characteristics of fibromyalgia patients compared with healthy controls.

OBJECTIVE: To assess structural social network characteristics and perceived loneliness in fibromyalgia syndrome (FMS) patients and healthy controls. METHODS: A cross-sectional, retrospective, case-control design was employed using a structured interview and a self-report questionnaire. We studied 25 female FMS patients and 25 matched healthy female controls. RESULTS: FMS patients had statistically significantly (P < 0.05) more intimate friends (mean 4.5) and more health care providers (mean 1.5) than did controls (2.3 and 0.0, respectively). The FMS patients more often initiated the contact with family members (mean 2.1) than did controls (mean 0.8). FMS patients did not perceive themselves as lonelier than controls perceived themselves. While there was a significant negative correlation between loneliness and social network variables among the controls, this relationship was not significant among the FMS patients. Among the patients, there was a strong correlation between the total social network size and the number of intimate friends, whereas in controls, the mean number of acquaintances was strongly correlated with the total network size. CONCLUSION: Compared to healthy controls, the social networks of FMS patients presented more linkages with intimate friends, family members, and health care providers. The lack of correlation between loneliness and social network variables for FMS patients is not what might be expected from social support theory. The assessment of structural social network characteristics along with social support variables may add to our understanding of the social functioning of FMS patients.

Adult↗
PubMed1996

Clinical and epidemiologic aspects of ankylosing spondylitis and spondyloarthropathies.

In the past decade the concept of spondyloarthropathy has become well established, and appropriate classification criteria have been developed. Now it is time to better define the terms in common use in order to facilitate scientific communication. Recently, new therapeutic approaches have been tested, but the design of some of these studies is weak. Clearly, the outcome of ankylosing spondylitis and spondyloarthritis is multidimensional. A number of new instruments for the assessment of ankylosing spondylitis are now available, but there is a need for core sets of outcome measures appropriate for the different settings in which assessment is done. Although criteria intended for use in epidemiologic studies might be useful in daily clinical practice to establish a diagnosis, improved recognition of the different elements of ankylosing spondylitis and spondyloarthritis requires more "problem orientation" and less "disease orientation."

Humans↗
PubMed1995

Factors related to change in global health after group physical therapy in ankylosing spondylitis.

The purpose of this study was to evaluate how improvements in global health in patients with ankylosing spondylitis (AS), who had received group physical therapy, were associated with changes in physical functioning and other outcome measures. Sixty-seven AS patients from 2 outpatient departments (modified New York criteria) received group physical therapy weekly. After 9 months we studied the following variables to explain changes in global health: disease duration, spinal mobility, fitness, functional status (SIP, HAQ and Functional Index), pain, stiffness, and articular and enthesis indices. Change scores were calculated as baseline values minus scores at 9-month follow-up. Personality traits (neuroticism, social inadequacy, self-esteem and health locus of control) and loneliness were also included as possibly explanatory variables. Patient's assessment of change in global health after 9 months of group physical therapy was self-reported on a 10 cm visual analogue scale (-5 = maximum worsening, 0 = no change, +5 = maximum improvement). Correlations were calculated between change in global health and all candidate explanatory variables. In this pre/post test design multiple and stepwise regression analyses were performed to study the relations between changes in global health and all explanatory variables. Pearson correlation coefficients between improved global health and the explanatory variables were significant for lower self-esteem (0.27) and improvements in chest expansion (0.31), fitness (0.32), HAQ-S (0.29), and stiffness (0.33). Regression analysis revealed 2 significantly explanatory steps: changes in fitness explained 16% of total variance of changes in global health, and changes in stiffness contributed an additional 11%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Ankylosing spondylitis and other B27 related spondylarthropathies.

Classification of ankylosing spondylitis and spondylarthropathies is now satisfactory, but assessment of ankylosing spondylitis and related disorders could be improved. Currently, we do not completely encompass the spectrum of relevant outcomes. Functional status and toxicity assessment are frequently lacking. Although a considerable amount of progress has been made over the past decade in the development of patient status measures, this has mainly been achieved in rheumatic diseases that are characterized by predominant involvement of peripheral joints. This achievement is less prominent in ankylosing spondylitis. It may be relatively easy to define activity of extra-articular manifestations such as uveitis, but it is more difficult to define activity, severity, progress and outcome of a disease like ankylosing spondylitis with predominant spinal involvement.

Disability Evaluation↗
PubMed1995

Assessing clinical competence: recognition of case descriptions of rheumatic diseases by general practitioners.

The objective of this study was to detect strengths and weaknesses in the diagnosis of rheumatic diseases by general practitioners in order to set up post-graduate training accordingly and to assess whether open-ended questions give results comparable with multiple choice-type questions. Fifty-one general practitioners were given eight written cases: rheumatoid arthritis (RA), ankylosing spondylitis (AS), reactive arthritis, psoriatic arthritis (PsA), systemic lupus erythematosus (SLE), gout, polymyalgia rheumatica and pseudogout. Only signs and symptoms were provided. All cases were derived from real patients with a definite diagnosis. Each case was presented in both types of question formats. The cases were also presented to 23 rheumatologists. We found that in the open-ended question format 57.1% of the general practitioners gave the correct answers. Cases of RA, AS, gout and PsA were correctly diagnosed by > 70% of the general practitioners. Cases of polymyalgia rheumatica and reactive arthritis were correctly diagnosed by 55 and 39% of the general practitioners, respectively. The cases of pseudogout and SLE were correctly diagnosed by less than 11% of the general practitioners. Fifty-two per cent of the general practitioners gave the correct answers to the multiple choice-type questions. There was no statistical difference in the correct answers between the open-ended questions and the multiple choice-type questions. We concluded that assuming generalization of the results, training of general practitioners should include polymyalgia rheumatica, reactive arthritis, SLE and pseudogout.

Clinical Competence↗
PubMed1995

Methodological issues of patient utility measurement. Experience from two clinical trials.

This article explores various methodological issues of patient utility measurement in two randomized controlled clinical trials involving 85 patients with fibromyalgia and 144 with ankylosing spondylitis. In both trials one baseline and two follow-up measurements of the patients' preferences for their own health state and several hypothetical states were performed using the rating scale and the standard gamble methods. It was confirmed that standard gamble scores are consistently higher than rating scale scores for both the experienced and the hypothetical states. The 3-month test-retest reliability for hypothetical states measured by intraclass correlation coefficients ranged from 0.24 to 0.33 for the rating scale and from 0.43 to 0.70 for the standard gamble. Although the reproducibility is not high, the group mean scores are fairly stable over time. Mean standard gamble scores tend to differ depending on the way the measurements are undertaken. Utilities elicited with chained gambles were significantly higher than utilities elicited with basic reference gambles. At the individual level some inconsistent responses occurred. However, more than 70% of these fell within the bounds of the measurement error, which ranged from 0.11 to 0.13 on the standard gamble (0-1 scale) and from 8 to 10 on the rating scale (0-100 scale). The large number of negative utilities for the severe hypothetical state, which was used as an anchor point in the chained gambles, and the magnitude of these negative utilities (down to -19) calls for intensified research efforts to handle these responses in utility calculations.

Adult↗
PubMed1995

Patient utilities in fibromyalgia and the association with other outcome measures.

OBJECTIVE: To compare in patients with fibromyalgia (FM) utilities derived by rating scale and standard gamble methods; to gain insight into construct validity by relating utility values to other outcome measures; to assess the sensitivity to change of utilities. METHODS: A total of 73 patients with FM were randomized into one of 3 groups: low impact fitness training, biofeedback, or controls. At baseline and after 6 mo the Maastricht Utility Measurement Questionnaire was applied. By means of both the rating scale and standard gamble method patients were asked to value their own health status. Construct validity of patient utility measurements was evaluated by Spearman correlation and multiple regression of baseline values with pain, stiffness, patient's global assessment, Sickness Impact Profile (SIP), modified Health Assessment Questionnaire and Arthritis Impact Measurement Scale (AIMS). Sensitivity to change was assessed against changes in these outcomes. RESULTS: Rating scale utilities correlated significantly (p < 0.05) with patient's global assessment (rs = 0.53), pain (rs = -0.47), SIP (rs = -0.43), and with 9 of 11 dimensions of the AIMS (rs ranging from 0.23 to 0.62). Standard gamble utilities correlated significantly with mobility, pain, and arthritis impact of the AIMS scale (rs from 0.22 to 0.36) and with pain by visual analog scale (rs = -0.24) and patient's global assessment (rs = 0.32). Multiple regression analysis showed that patient's global assessment explained 41% (rating scale) and 10% (standard gamble) of total variance in baseline utilities. Also, 16% of the variance in change in rating scale utility values was explained by changes in patient's global assessment. In contrast, variance of changes in standard gamble utility values was not explained significantly by changes in other disease outcomes. CONCLUSION: Rating scale utilities correlated more strongly with disease outcome measures than standard gamble utilities. Also, construct validity for the rating scale was better than for the standard gamble. In FM, utility measurement is sensitive to the method chosen to elicit patient priorities.

Adolescent↗