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Biomedical subjects

A L Verbeek

Publications and source records attributed to A L Verbeek.

At least 145 records · Page 8Linked to original sources
PubMed1992

Early detection of patients with fast progressive asthma or chronic bronchitis in general practice.

The morbidity and mortality due to asthma and chronic bronchitis are still rising in several countries. The aim of this study was to investigate whether early detection of patients with fast progressive asthma or chronic bronchitis in general practice was possible from a cross-sectional assessment of symptoms, smoking behaviour, quality of life, physical signs of the chest, allergy, and lung function. Data of 162 patients who had participated in a long-term randomized controlled intervention study in general practice were analysed. Fifty-six out of the 162 patients showed fast progressive disease (FPD, a rapid annual decline in FEV1 in combination with a high exacerbation rate). Measurements at the start of the study were used in a logistic regression analysis in order to detect the patients at risk (with FPD). A lower maximal expiratory flow at 50% of expired volume (MEF50) was related to an increased risk of FPD in both asthma and chronic bronchitis (relative risks of 16.8 and 8.0 respectively, p less than 0.05). Most lung function indices, but also quality of life and pack years, were significant predictors of FPD in chronic bronchitis (p less than 0.05). However, it was not possible to detect FPD reliably with these predictors separately or even with the combination of several relevant clinical variables; 18% of the patients with chronic bronchitis and 22% of the patients with asthma were still misclassified. It was concluded from this study that more than one measurement over time (monitoring) is necessary to detect the patients at risk. Monitoring should include assessments of objective ventilatory function indices (PEFR, FEV1 or MEF50).

Adult↗
PubMed1992

Prostate cancer and work environment.

A case-referent study was conducted to investigate the relation between occupation and prostate cancer. For this study 109 cases and 209 referents (patients with prostate hyperplasia) were selected from the registries of four hospitals. Self-administered questionnaires were mailed to all subjects to obtain information on their occupational history. The response was 85%. Nonsignificant elevated risks were found for farmers, metal workers, mechanics and repairmen, traders, and salesmen. A significant risk excess was observed for teachers (n = 6; odds ratio [OR] 4.25; 95% confidence interval [CI] 1.14-15.79). The OR calculated for farmers older than 70 years was also significant (n = 9; OR 2.12; 95% CI 1.03-4.38). Literature was searched for additional evidence of excess risk among farmers, metal workers, mechanics and repairers, and to find clues for actual risk factors. From the review it can be concluded that these occupations may have a slightly increased risk for prostate cancer. However, the actual risk factors are uncertain.

Aged↗
PubMed1991

Bronchodilator treatment in moderate asthma or chronic bronchitis: continuous or on demand? A randomised controlled study.

OBJECTIVE: To examine the effect of bronchodilator treatment given continuously versus on demand on the progression of asthma and chronic bronchitis and to compare the long term effects of a beta 2 adrenergic drug (salbutamol) and an anticholinergic drug (ipratropium bromide). DESIGN: Two year randomised controlled prospective 'crossover' study in which patients were assigned to one of two parallel treatment groups receiving continuous treatment or treatment on demand. SETTING: 29 general practices in the catchment area of the University of Nijmegen. PATIENTS: 223 patients aged greater than or equal to 30 with moderate airway obstruction due to asthma or chronic bronchitis, selected by their general practitioners. INTERVENTIONS: 1600 micrograms salbutamol or 160 micrograms ipratropium bromide daily (113 patients) or salbutamol or ipratropium bromide only during exacerbations or periods of dyspnoea (110). No other pulmonary treatment was permitted. MAIN OUTCOME MEASURES: Decline in ventilatory function and change in bronchial responsiveness, respiratory symptoms, number of exacerbations, and quality of life. RESULTS: Among 144 patients completing the study, after correction for possible confounding factors the decline in forced expiratory volume in one second was -0.072 l/year in continuously treated patients and -0.020 l/year in those treated on demand (p less than 0.05), irrespective of the drug. The difference in the decline in patients with asthma was comparable with that in patients with chronic bronchitis (asthma: 0.092 v -0.025 l/year; chronic bronchitis: -0.082 v -0.031 l/year). Bronchial responsiveness increased slightly (0.4 doubling dose) with continuous treatment in chronic bronchitis, but exacerbations, symptoms, and quality of life were unchanged. Salbutamol and ipratropium bromide had comparable effects on all variables investigated. CONCLUSIONS: Continuous bronchodilator treatment without anti-inflammatory treatment accelerates decline in ventilatory function. Bronchodilators should be used only on demand, with additional corticosteroid treatment, if necessary.

Adult↗
PubMed1991

Estimation of the frequency of the muscular pain-fasciculation syndrome and the muscular cramp-fasciculation syndrome in the adult population.

A nationwide two-phase survey was carried out of the adult population of the Netherlands regarding fasciculation, muscle pain and muscle cramp. We conducted a population-based telephone interview with 780 Dutch adults, followed by a questionnaire covering more clinical details, filled out by 311 subjects, who had been interviewed by telephone previously. From these data the frequencies of fasciculation (men 50%, women 61%), muscle cramp (men 28%, women 42%) and muscle pain (men 48%, women 60%) in the Dutch adult population in 1988 were estimated. The combined occurrence of frequent fasciculation and frequent muscle cramp as well as of frequent fasciculation and frequent muscle pain was reported only sporadically. Although the muscular pain-fasciculation syndrome and the muscular cramp-fasciculation syndrome represent combinations of common neuromuscular phenomena, their occurrence in the general population proved to be rare. This finding supports their clinical identity as distinct motor unit hyperactivity syndromes rather than mere coincidences of fasciculation, muscle cramp and muscle pain.

Adult↗
PubMed1991

Breast-conserving treatment or mastectomy in early breast cancer: a clinical decision analysis with special reference to the risk of local recurrence.

A clinical decision analysis was performed to judge the impact of local recurrences after breast-conserving treatment (BCT) on the (quality-adjusted) life expectancy of breast cancer patients. A life-long follow-up of two patient groups, one of which had undergone mastectomy and one BCT, was simulated by a Markov model of medical prognosis. Data used in the model originated from the literature. Since results in the source papers were not split according to stage, we performed two analyses: one with data from all source studies (T1 and T2) and one with data from source studies, concerning only T1 patients. In both analyses, the conclusion was that BCT yields better quality-adjusted life expectancy than mastectomy. Sensitivity analysis, however, identified subgroups of patients who should preferably undergo mastectomy. These subgroups are: patients preferring mastectomy to BCT, patients with a high risk of local recurrence, young patients and patients at high age, if they also have a high local recurrence risk. For these groups, patient preferences should play a major role in recommending treatment.

Adult↗
PubMed1991

A proposal for short-term quality control in breast cancer screening.

Current proposals for a monitoring and evaluation system in breast cancer screening programmes focus on mortality reduction. Here emphasis is laid on the prevention of too high a number of false-positive screening results, i.e. no subsequent demonstration of malignancy. By comparing the specificity of the screening test, the positive predictive value and the detection rate with reference values, the screening performance can be measured in a very early phase of the programme, even before the registration results on interval cancers become available. The proposed average reference values for the first screening round are 99.2%, 40% and 5.4/1000, respectively. Measures specifically for the age groups 45-49, 50-59 and 60-69 will be given, thus allowing improvements to be made if necessary.

Aged↗
PubMed1990

[Digital mammography is very useful in mass screening of breast cancer].

Mammograms made between 1981 and 1989 in the Nijmegen screening programme for breast cancer were retrospectively reviewed. Those made before detection of breast cancer showed signs of tumour growth in the place of the subsequently detected malignancy in 22% of the cases. A work station was set up for image digitization and image processing. Display with optimal contrast and image processing of mammograms is possible. Diagnoses based on digitized mammograms displayed on a monitor were as good as those based on the conventional images on film. Automatic detection of image features has been investigated. A procedure for automatic detection of microcalcifications was developed. This research is important for optimalization of diagnosis in screening and because of the expected introduction of direct digital imaging techniques.

Breast Neoplasms↗
PubMed1990

[Utility assessment in clinical decision making].

In clinical decision analysis a quantitative value is attached to a longevity or a life quality by means of utility assessment. The actual value of the utility can determine the result of the decision analysis. In this article utility theory is briefly discussed. Four kinds of utility tests (direct scaling methods, the basic reference gamble, the time trade-off test and additive conjoint measurement) are introduced on the basis of an example and their pros and cons are discussed. It is concluded that additive conjoint measurement has the best formal infrastructure, but that the test method is not always easily applicable.

Choice Behavior↗
PubMed1990

A model for breast cancer screening.

A model for breast cancer screening has been developed. When the appropriate screening policy is specified, the model reproduces the detection rates and the incidence of interval cancers as observed in the recent screening projects in Utrecht and Nijmegen, the Netherlands. The model-predicted mortality rate reduction is in accordance with the results of the Kopparberg/Ostergötland randomized trial in Sweden. Key parameters of the model are the duration of the preclinical stages and the sensitivity of mammography. The average duration is approximately 2 years at age 40 and increases to approximately 5 years at age 70. The sensitivity is high (approximately 95%) for tumors larger than 1 cm. The model is used in the prospective evaluation of effects and costs of various screening policies.

Adult↗
PubMed1990

[A survey of the epidemiology of breast cancer in The Netherlands].

Breast cancer is responsible for the main part of the total cancer incidence (+/- 30%) and cancer mortality (+/- 20%) among Dutch women. Due to aging of the Dutch population alone, the absolute numbers of breast cancer cases and deaths will increase considerably. Risk factors for breast cancer give no clues for primary prevention. By means of periodic screening patients are diagnosed at an earlier stage of disease, with a better prognosis. Even without a screening programme symptomatic women are diagnosed at earlier stages of disease. This paper gives a review of trends in breast cancer incidence and mortality in The Netherlands, as well as a risk profile of breast cancer patients and the relation between disease stage and survival. Its purpose is to obtain a better insight into the intended effects of the national breast cancer screening programme.

Adult↗
PubMed1990

[Observed effects of the mass screening program for breast cancer in Nijmegen in 1975-1986].

Since January 1975, the start of the screening programme for breast cancer in the city of Nijmegen, The Netherlands, over 14 years have elapsed. Data up to the end of 1986 have been processed and are presented in this article. The younger the birth cohort, the higher the attendance rate. In the course of the screening programme, attendance rates decline. Referral rates are highest in the first screening round and for the eldest birth cohort. Detection rates increased during the most recent screening rounds, after an initial decrease during the earliest rounds. They are higher for the eldest birth cohort also. The relative number of interval carcinomas is highest among younger women (as related to the screening-detected carcinomas).

Adult↗
PubMed1990

Shortcut method to calculate the sample size in trials of screening for chronic disease.

One of the first questions arising in the planning of a randomized trial to evaluate mortality reduction by screening concerns the sample size of the trial required to detect an expected mortality reduction in the study group for given significance level alpha, and power 1 - beta. If estimates exist of the underlying average annual incidence rate of the disease ra and the annual mortality rate delta a or survival data for patients in the population under consideration before screening started, then a simple formula for the probability of dying from the disease within T years after entry into the trial can be given for the control group. Standard formulas may then be used for sample size calculations in randomized trials, which compare the risk of death from the disease in the control and the study group accrued at T years after entry. A simple correction for loss of follow-up, due to mortality from other causes or, for instance, migration is possible.

Age Factors↗
PubMed1990

Use of recombinant RNP peptides 70K and A in an ELISA for measurement of antibodies in mixed connective tissue disease: a longitudinal follow up of 18 patients.

In a three year prospective study disease activity variables and levels of antibody against the RNP-peptides 70K and A were measured in 18 patients with mixed connective tissue disease. Antibody measurement entailed use of cloned autoantigens in an enzyme linked immunosorbent assay (ELISA). Fluctuations in antibody levels against 70K and A were most commonly noted in patients who also had changes in disease activity, but these changes in serology and disease activity were synchronous in only a minority of the episodes. Even major disease flares were associated with changes in anti-A levels in only a few, and with changes in anti-70K levels in none of the episodes. The data indicate that measurements of anti-70K and anti-A levels are not useful in monitoring disease activity or response to treatment in mixed connective tissue disease, and suggest that these antibody specificities do not play a direct part in the pathogenesis of disease manifestations.

Antibodies↗
PubMed1990

The presence of an extensive intraductal component following a limited excision correlates with prominent residual disease in the remainder of the breast.

Previous studies of patients with infiltrating ductal breast cancer treated with conservative surgery (ie, limited excision) and radiotherapy have indicated that the presence of an extensive intraductal component (EIC) in the excision specimen is highly associated with subsequent breast recurrence. The reason for this association is not clear, but possible explanations include the presence of more extensive disease in the breast or increased radiation resistance among tumors with an EIC (EIC+) compared with those without (EIC-) tumors. To investigate this association further, we related the presence or absence of an EIC in the primary tumors of 214 women who underwent mastectomy to the likelihood of finding additional foci of cancer in their mastectomy specimens using a correlated pathologic-radiologic mapping technique. Primary tumors that were EIC+ were significantly more likely to have carcinoma in the remainder of the breast than those which were EIC--(74% v 42%; P = .00001). This difference was primarily due to the presence of residual intraductal carcinoma. Seventy-one percent of EIC+ patients had residual intraductal carcinoma compared with 28% of EIC-patients (P less than .00001). In particular, 44% of EIC+ patients had "prominent" residual intraductal carcinoma compared with 3% of EIC-patients (P less than .00001). We conclude that patients whose tumors contain an EIC more frequently have a large subclinical tumor burden in the remainder of the breast compared with patients whose tumors do not contain an EIC. This observation may explain the association between EIC and subsequent breast recurrence when patients are treated with a limited excision before radiotherapy.

Breast↗