Search PubMed⌕ Search

Biomedical subjects

P D Bezemer

Publications and source records attributed to P D Bezemer.

At least 19 recordsLinked to original sources
PubMed2003

Comparison of endocrine tests with respect to their predictive value on the outcome of ovarian hyperstimulation in IVF treatment: results of a prospective randomized study.

BACKGROUND: This study was designed to compare endocrine tests [clomiphene citrate challenge test (CCT), exogenous FSH ovarian reserve test (EFORT) and basal FSH, basal estradiol (E(2)) and basal inhibin B as an integral part of all CCT and EFORT], with respect to their ability to estimate the stimulable cohort of follicles in the ovaries (ovarian capacity) and to analyse which test or combination of tests would give the best prediction of ovarian capacity. METHODS: A total of 110 regularly menstruating patients, aged 18-39 years, participated in this prospective study, randomized by a computer-designed 4-block system study into two groups. Fifty-six patients underwent a CCT, and 54 patients underwent an EFORT. In all patients, the test was followed by an IVF treatment. The result of ovarian hyperstimulation during IVF treatment, expressed by the total number of follicles, was used as gold standard. RESULTS: Univariate linear regression analysis showed that the best correlation with the number of follicles after ovarian hyperstimulation (Y) is found by the inhibin B increment (InhB incr.) in the EFORT (Y = 3.957 + 0.081 x InhB incr. (95% CI 0.061-0.101); r = 0.751; P < 0.001). Multiple linear regression analysis showed a significant contributing value of the variables basal FSH, E(2) increment of the EFORT and inhibin B increment to the basic model with the variable age. The best prediction of ovarian capacity (Y) was seen when E(2) increment and inhibin B increment were used simultaneously in a stepforward multiple regression prediction model [Y = 2.659 + 0.052 x InhB incr. (0.026-0.078) + 0.027 x E(2) incr. (95% CI 0.012-0.054); r = 0.796; P < 0.001]. The CCT could not be used in a prediction model. CONCLUSIONS: The EFORT is the endocrine test which gives the best prediction of ovarian capacity.

Adolescent↗
PubMed2003

Patch-test-induced subjective complaints.

BACKGROUND: Many patients report subjective complaints during epicutaneous patch testing. OBJECTIVE: To demonstrate the possible relationship between the occurrence of subjective complaints and patch testing. METHODS: All consecutive patients who were referred to our clinic for patch testing, during 1 year, were investigated to study a possible association of the patch test procedure and subjective complaints like tiredness, shakiness or feeling unwell. The patients were asked to fill in a form concerning subjective complaints on the days of the investigation. Only those without complaints on the day the patches were applied were included in the study (n=102). RESULTS: Of the 102 patients, 17 had complaints on both days 2 and 3, 14 only on day 2, 6 only on day 3 and 65 did not develop any complaints at all. The number of patients with complaints on both days 2 and 3 (n=17) was larger than was to be expected from chance (n=4.6; p<0.01). There was a significant correlation between the number of positive patch test reactions and the number of complaints on day 2 (r=0.19; p<<0.001) and on day 3 (r=0.15; p<0.001). Positive patch tests were found in 72.2% of the patients who reported the complaint of shakiness; this proportion is significantly higher than expected from chance (p<0.05). CONCLUSION: The results confirm those of our earlier study and demonstrate that patch testing can cause subjective complaints, especially when positive patch tests are present.

Adolescent↗
PubMed2002

[Systematic reviews in practice. X. Searching, selecting and the methodological assessment of diagnostic evaluation research].

Literature concerning the value of diagnostic tests is poorly indexed in electronic bibliographical databases. An extensive, sensitive and specific search strategy for evaluation of a diagnostic test in Medline is a combination of key words or text words concerning the diagnostic test with: 'sensitivity and specificity' (exploded), 'mass screening' (exploded), 'reference values', 'false positive reactions', 'false negative reactions', 'specificit$.tw', 'screening.tw', 'false positive$.tw', 'false negative$.tw', 'accuracy.tw', 'predictive value$.tw', 'reference value$.tw', 'roc$.tw' or 'likelihood ratio$.tw'. Inclusion and exclusion criteria select publications which meet certain minimum requirements, such as the presence of an accepted reference standard, a clear definition of 'diseased', and the presence of a suitable outcome measure. The methodological assessment list should contain a number of validity criteria as well as a number of criteria by which to measure the extent to which the study results can be generalised. Important assessment criteria that may affect the diagnostic value of the test are: study design, blinding, use of different reference standards, the absence of details about the diagnostic criteria for the diagnostic test and insufficient information about the study population.

Diagnostic Tests, Routine↗
PubMed2002

High-risk human papillomavirus clearance in pregnant women: trends for lower clearance during pregnancy with a catch-up postpartum.

We followed 353 women referred with abnormal cervical cytology in a non-intervention cohort study. In 91 pregnant women we compared high-risk human papilloma virus rates in the subsequent trimesters and postpartum in comparison to 262 non-pregnant women. High-risk human papilloma virus clearance was compared with 179 high-risk human papilloma virus positive non-pregnant women. Our main questions were: (1) do high-risk human papilloma virus rates change during pregnancy?; and (2) is there any difference between high-risk human papilloma virus clearance in pregnant and non-pregnant women? Women were monitored 3-4 monthly by cytology, colposcopy, and high-risk human papilloma virus testing. The median follow-up time was 33 months (range 3-74). Non-pregnant women showed prevalence rates of high-risk human papilloma virus of 64, 57, 53, and 50%, respectively, in four subsequent 3-months periods since the start of the study. These high-risk human papilloma virus rates were higher than in the three trimesters of pregnancy, and during the first 3 months postpartum, i.e. 50, 44, 45, and 31%, respectively. Postpartum only, this difference was statistically significant (P=0.004). Paired comparisons of high-risk human papilloma virus prevalence rates of the different trimesters with the postpartum rate showed (McNemar test) decreased rates: first trimester: 18% (P=0.02), second trimester: 13% (P=0.02) and third trimester: 23% (P<0.005). Such a phenomenon was not found in non-pregnant women. Pregnant women showed a trend for increased high-risk human papilloma virus clearance during the third trimester and postpartum compared to non-pregnant women (hazard ratios 3.3 (0.8-13.7) and 4.6 (1.6-12.8), respectively). These results suggest a lowered immune-response against human papilloma virus during the first two trimesters of pregnancy with a catch-up postpartum.

Adult↗
PubMed2002

Cost-effectiveness of screening for the possible development of cancer in patients with oral lichen planus.

INTRODUCTION: Several authors have expressed the view that patients with oral lichen planus (OLP) are at increased risk of developing oral cancer. Since OLP cannot be effectively treated, regular screening for the possible development of oral cancer might be considered. OBJECTIVES: (i) To calculate costs and effectiveness of screening for oral cancer in OLP patients with a decision model; (ii) to compare the cost-effectiveness of different screening scenarios; and (iii) to perform a sensitivity analysis of several variables used in this model. METHODS: Costs and effectiveness of a population of 100,000 OLP patients, being either screened or not screened for oral cancer, were calculated for the period of 1 year. Health gain was expressed as quality adjusted live years (QALY's) and equivalent lives saved (ELS). Cost-effectiveness was expressed as extra costs (costs of screening minus costs of no screening) per ELS. Then, the outcome was compared with the cost-effectiveness of a different screening scenario. Finally, the effect of varying the variables: (i) costs of cancer treatment; (ii) annual malignant transformation rate (MTR); (iii) sensitivity and specificity of an oral examination; and (iv) proportion of cancers found in stage I on extra costs per ELS were assessed in a sensitivity analysis. RESULTS: The health gain from screening was 592 QALY's or the equivalent of 23.68 lives saved, costing 1,265,229 dollars, meaning that one ELS costed 53,430 dollars. Increase of cancer-treatment costs will significantly decrease the costs per ELS. When the MTR is lower than 0.4% per year, extra costs per ELS will increase exponentially. The effect of sensitivity and specificity of an oral examination in detecting oral cancer on cost-effectiveness seems to be substantial. When the proportion of cancers found in stage I can be increased from 40% (without screening) up to at least 60% after screening, extra costs per ELS will decrease exponentially. CONCLUSIONS: Screening for oral cancer in OLP patients, based on the presently used model, seems attractive. However, varying the several variables in the decision model has a significant impact on the final costs and effectiveness. Only, when additional information about these variables will become available, a more precise and realistic calculation can be performed.

Cell Transformation, Neoplastic↗
PubMed2002

The clinical relevance of epithelial dysplasia in the surgical margins of tongue and floor of mouth squamous cell carcinoma: an analysis of 37 patients.

BACKGROUND: The clinical relevance of the presence of epithelial dysplasia in the margins of surgically removed oral squamous cell carcinoma is still unclear. METHOD: In a retrospective study, the presence of mild or moderate epithelial dysplasia in the surgical margins of tongue and floor of mouth squamous cell carcinoma was examined histologically. Patients with tumor cells within 0.5 cm of the surgical margins were excluded. Also patients with severe dysplasia were excluded, as this is usually regarded as carcinoma in situ. Patients that received postoperative irradiation were also excluded. Only patients who completed a follow-up period of five years were included. All together, a total number of 37 patients fulfilled the inclusion criteria. RESULTS: Epithelial dysplasia was observed in 7 out of the 37 patients. Five of these patients, and two of the 30 patients with no dysplasia, had a local recurrence (P < 0.01). CONCLUSION: The presence of mild or moderate epithelial dysplasia in the margins of surgically removed oral squamous cell carcinoma carries a significant risk for the development of local recurrence. However, it should be noted that this study was of a retrospective nature and that the group of patients with epithelial dysplasia in the surgical margins was rather small. On the other hand, the inclusion criteria were somewhat strict, by limiting the oral subsite to tongue/floor of mouth, by excluding patients in whom tumors cell were found within 0.5 cm of the surgical margins and by excluding patients who received postoperative radiotherapy, amongst others.

Carcinoma, Squamous Cell↗
PubMed2001

Towards a curriculum for the consultant biostatistician: identification of central disciplines.

The variation in the background of biostatistical consultants is huge. This varying background in formal education complicates communication. It may obscure clients' expectations as well as any discussion on qualifications and registration. To tackle these disadvantages as well as to facilitate the training of a new colleague, we need to find common ground. The aim of this paper is to identify the central disciplines which constitute the foundation of biostatistical consultancy. Any task-aimed curriculum should be based on these disciplines. Curriculum design theory was used to guarantee a logical and rational process. The result is the identification of a sextet of disciplines: applied statistics; methodology; epidemiology; communication; computational science, and personal effectiveness.

Biometry↗
PubMed2001

Cytological regression and clearance of high-risk human papillomavirus in women with an abnormal cervical smear.

We studied the natural course of high-risk human papillomavirus (HPV) infection and cytological regression in women referred for colposcopy because of abnormal cervical smears. We found that high-risk HPV clearance preceded regression of cervical lesions by an average of 3 months. The cumulative 1-year rate of cytological regression was similar in women with mild and moderate dyskaryotic cervical smears. Thus, retesting of high-risk HPV after 6 months in women with mild to moderate dyskaryosis predicts cytological regression.

Adult↗
PubMed2001

Smallest real difference, a link between reproducibility and responsiveness.

The aim of this study is to show the relationship between test-retest reproducibility and responsiveness and to introduce the smallest real difference (SRD) approach, using the sickness impact profile (SIP) in chronic stroke patients as an example. Forty chronic stroke patients were interviewed twice by the same examiner, with a 1-week interval. All patients were interviewed during the qualification period preceding a randomized clinical trial. Test-retest reproducibility has been quantified by the intraclass correlation coefficient (ICC). the standard error of measurement (SEM) and the related smallest real difference (SRD). Responsiveness was defined as the ratio of the clinically relevant change to the SD of the within-stable-subject test-retest differences. The ICC for the total SIP was 0.92, whereas the ICCs for the specified SIP categories varied from 0.63 for the category 'recreation and pastime' to 0.88 for the category 'work'. However, both the SEM and the SRD far more capture the essence of the reproducibility of a measurement instrument. For instance, a total SIP score of an individual patient of 28.3% (which is taken as an example, being the mean score in the study population) should decrease by at least 9.26% or approximately 13 items, before any improvement beyond reproducibility noise can be detected. The responsiveness to change of a health status measurement instrument is closely related to its test-retest reproducibility. This relationship becomes more evident when the SEM and the SRD are used to quantify reproducibility, than when ICC or other correlation coefficients are used.

Adult↗
PubMed2001

Prevalence of diabetes mellitus, hypertension and cardiac complaints in a follow-up study of a Dutch PCOS population.

The aim of this study was to investigate the prevalence of diabetes mellitus, hypertension and cardiac complaints in a Dutch population with polycystic ovarian syndrome (PCOS) and to compare the results with the prevalence of these conditions in the Dutch female population, as retrieved from the Netherlands Health Interview Survey of Statistics Netherlands. A total of 346 PCOS patients were interviewed by telephone, with a mean age of 38.7 years (range 30.3--55.7) and a mean body mass index of 24.4 (range 17.5--55.8). Diabetes occurred in eight (2.3%), hypertension in 31 (9%) and cardiac complaints in three (0.9%) of the women. The prevalence of diabetes and hypertension differed significantly from the prevalence of these conditions in the Dutch female population (both P < 0.05). In PCOS women aged 45--54 years (n = 32) the prevalence of diabetes was four times higher (P < 0.05) and of hypertension 2.5 times higher (P < 0.01) than the prevalence of these conditions in the corresponding age group of the Dutch female population. Hypertension also occurred significantly (P < 0.05) more in the younger (35--44 years) PCOS group (n = 233), but this age group was significantly more obese (P < 0.01) when compared with figures of obesity of the Dutch female population. In conclusion, our data show that in a follow-up study of a relatively lean PCOS population, the prevalence of diabetes mellitus and hypertension was increased when compared with the Dutch female population, especially in women aged 45--54 years.

Adult↗
PubMed2001

Health outcomes of asthma and COPD patients: the evaluation of a project to implement guidelines in general practice.

OBJECTIVE: To evaluate a project to implement guidelines on the management of patients with asthma or chronic obstructive pulmonany disease (COPD) in terms of the health outcomes of these patients. DESIGN: A before-and-after study of 1 year with a non-randomized but comparable reference group. SETTING: General practices in the Netherlands. STUDY PARTICIPANTS: Two-hundred and eighty patients from 14 practices in the intervention group and 90 patients from five practices in the reference group (receiving usual care). INTERVENTION: The project included a comprehensive implementation programme, involving identification of barriers, documentation of the care provided, specific education, feedback on compliance with the guidelines, and peer review. This project has been found to bring the process of care more in agreement with the guidelines. MAIN OUTCOME MEASURES: Mean peak expiratory flow rate (PEFR) as a percentage of the predicted value, number of days with a diurnal variation in PEFR > or = 15%, number of days with respiratory symptoms (all recorded by patients for a period of 14 days), and perceived health status (Nottingham Health Profile). RESULTS: After 1 year, the intervention group showed statistically significant improvements with regard to the mean PEFR, the diurnal variation in PEFR, respiratory symptoms and the pain score of the Nottingham Health Profile. Comparing the changes within the intervention group with the changes within the reference group, only a positive effect of the intervention on the mean PEFR was found. CONCLUSION: The comprehensive implementation programme improved the lung function and symptoms of asthma and COPD patients in the intervention group. However, in comparison with a reference group, the positive effect on the lung function was only small.

Adult↗
PubMed2001

Predictors of radiographic joint damage in patients with early rheumatoid arthritis.

OBJECTIVE: To determine factors at diagnosis, associated with radiographic damage at diagnosis and after one year, in patients with early rheumatoid arthritis (RA). METHODS: New patients with early RA were followed up for one year. Possible prognostic factors were duration of complaints, morning stiffness, disease activity score (DAS28), functional status (Health Assessment Questionnaire (HAQ) score), rheumatoid factor (IgM RF), and C reactive protein (CRP). Outcome was defined as radiographic damage of the hands and feet (Sharp/van der Heijde score). For the statistical analysis, one way analysis of variance and a forward stepwise logistic regression model was used. RESULTS: 130 patients with RA (68% female; median age 64 years, range 21-86) were included. Despite the fact that the median duration of complaints was short (15 weeks, range 2-106) the radiographic damage at diagnosis was significantly correlated with the duration of complaints (p<0.05). Patients with a duration of complaints of >34 weeks had significantly more radiographic joint damage at diagnosis than patients with a shorter duration of complaints. Radiographic progression at one year was correlated with high radiographic joint damage, high CRP level, and a positive IgM RF at entry. CONCLUSIONS: In early RA, the number of radiographic lesions was correlated with a longer duration of complaints at the first visit. Progression of these lesions was predicted by a high baseline joint damage, high CRP level, and a positive IgM RF. Further reduction of the delay in referral and early treatment may further decrease joint damage in patients with recent onset polyarthritis.

Activities of Daily Living↗
PubMed2001

The oedema-protective effect of Lycra support stockings.

BACKGROUND: Oedema may be an early sign of chronic venous insufficiency (CVI), but swelling of the lower legs is a common phenomenon in many people. The distinction between physiological swelling and CVI is not clear. There is a gradual transition between healthy legs and the early stages of CVI. In case of CVI, medical elastic compression stockings are used in order to prevent oedema completely. In case of healthy people without demonstrable CVI, no medical stockings are required in the prevention of oedema but stockings exerting less compression. OBJECTIVE: The aim of this study was to investigate the effect of mild compression on the development of swelling of the legs and the effect on subjective complaints in healthy subjects. METHODS: The diurnal volume change (DVC) of the lower legs during full working days was monitored with an optical leg volume meter in 118 healthy volunteers (60 males, 58 females) without objective symptoms of CVI. The DVCs after wearing two kinds of class I support stockings (X: average pressure at the ankle of almost 14 mm Hg; Y: almost 18 mm Hg) were compared with the DVC after wearing a control stocking (Z: almost 6 mm Hg). Also, the effect on subjective feelings of the legs was noted. RESULTS: It appeared that healthy people have a mean daily volume increase of the legs of 2.3% in females and 1.6% in males. Mild compression stockings reduced this daily increase with 31 and 18% in males and females, respectively, by stocking X and 37 and 32% by stocking Y. Subjective feelings occurred in 57% of all cases. A beneficial effect on subjective feelings, in particular of tired and swollen legs, was found. A difference in this beneficial effect between stocking X and Y was not obvious. CONCLUSIONS: Mild compression stockings reduce diurnal oedema and unpleasant feelings of the legs in healthy individuals.

Adult↗
PubMed2001

Tobacco usage in relation to the anatomical site of oral leukoplakia.

OBJECTIVE: Tobacco usage is the most important known aetiological factor in the development of oral leukoplakia. The purpose of this study was to investigate the possible relation of tobacco usage to the anatomical site of the leukoplakia. SUBJECTS AND METHODS: Clinical data regarding tobacco usage and localisation of leukoplakia obtained from 166 patients with oral leukoplakia. RESULTS: Leukoplakias in the floor of mouth appeared to be statistically significantly more often present in smokers than in non-smokers, compared to all other oral sites (P < 0.001; OR = 8.47 and 18.13 for men and women, respectively). On the contrary, leukoplakias on the borders of the tongue were statistically significantly more common among non-smokers, than smokers, compared to all other oral sites (P < 0.001; OR = 0.22 and 0.12 for men and women, respectively). CONCLUSION: The present study suggests that the influence of tobacco on the development of leukoplakia varies by anatomical site.

Adult↗
PubMed2001

Reproducibility and responsiveness of evaluative outcome measures. Theoretical considerations illustrated by an empirical example.

OBJECTIVE: This article outlines basic methods for quantifying reproducibility and responsiveness of evaluative outcome measures. METHODS: The background noise in stable patients provides the desired information to quantify the reproducibility. From this, the smallest real difference (SRD) for longitudinal differences can be derived. We propose to use the SRD to define responsiveness: from all patients who change according to an external criterion, we take the percentage that changes at least SRD on the outcome measure. A more complete picture of the responsiveness of the outcome measure arises when the receiver operating characteristic (ROC) is constructed, corresponding to all possible cut-off change scores. The proposed methods are illustrated with an empirical example. RESULTS: In the illustration the methods appeared to be very useful and complemented each other. We could evaluate whether the observed change score was larger than that expected due to chance. With the methods it was possible to evaluate both the ability of an instrument to detect change if there is a real change in health status (sensitivity to change) and the ability to detect absence of change if there is no real change (specificity to change). CONCLUSION: We presented the use of SRDs and ROC curves for quantifying reproducibility and responsiveness. We started with the basic notions and arrived at methods that are both understandable and useful.

Health Status Indicators↗
PubMed2000

The test of Lasègue: systematic review of the accuracy in diagnosing herniated discs.

STUDY DESIGN: A systematic review of the literature including statistical meta-analysis. OBJECTIVES: To evaluate published methods of the test of Lasègue or straight leg raising test and the cross straight leg raising test by using a recently developed criteria list and to summarize and explore reasons for variation in diagnostic accuracy. SUMMARY OF BACKGROUND DATA: Little evidence exists on the diagnostic accuracy of the widely used straight leg raising test and the cross straight leg raising test in diagnosing herniated discs in patients with low back pain. METHODS: MEDLINE and EMBASE searches up to 1997 showed 17 diagnostic publications evaluating the straight leg raising test with surgery as reference standard. Quality of methods was assessed with a specific checklist. Eleven studies were selected for statistical pooling. Sources of variation and heterogeneity were studied by meta-regression of the diagnostic odds ratio. RESULTS: All studies were surgical case-series at nonprimary care level. Verification-bias was obvious in one study. Pooled sensitivity for straight leg raising test was 0. 91 (95% CI 0.82-0.94), pooled specificity 0.26 (95% CI 0.16-0.38). Pooled diagnostic odds ratio was 3.74 (95% CI 1.2-11.4). Discriminative power was lower in recent studies, in studies with only inclusion of primary hernias, and with blind assessment of both the index-test (straight leg raising test) and the reference (surgery). For the cross straight leg raising test pooled sensitivity was 0.29 (95% CI 0.24-0.34), pooled specificity was 0.88 (95% CI 0.86-0.90), and the pooled diagnostic odds ratio 4.39 (95% CI 0.74-25.9). CONCLUSIONS: The diagnostic accuracy of the straight leg raising test is limited by its low specificity. Discriminative power decreased with a more valid design, a more homogenous case-mix, and year of publication. Although the studies may reflect everyday clinical practice, they do not enable a valid evaluation of the diagnostic accuracy of both tests. Diagnostic research should evaluate the validity of the complete diagnostic process and study the evidence of the added value of the different tests used. [Key words: sensitivity, specificity, diagnosis, meta-analysis, test of Lasègue, straight leg raising test]

Adult↗
PubMed2000

Increased risk of developing ankylosing spondylitis among first-born children.

OBJECTIVE: Studies in mice have demonstrated an increased risk of ankylosing enthesopathy in earlier litters compared with later-born offspring. In humans, birth order and maternal age as risk factors for ankylosing spondylitis (AS) have not been investigated previously. This study was undertaken to investigate whether first-born children have a higher risk of AS than later-born children and whether maternal age at delivery is another risk factor. METHODS: The birth order of 162 AS patients was compared with that of their healthy siblings, both for the total group and with stratification for maternal age at first delivery. Maternal age at the time of delivery of AS patients who were first-born children was compared with the mean maternal age at first delivery in the Dutch population. RESULTS: The number of first-born children with AS was significantly higher than would be expected in case of an equal risk between first-born and later-born children (26 versus 20 for families with 2 children [P = 0.029] and 63 versus 47.6 for all families [P = 0.004]). Also, the mean maternal age at first delivery was lower in mothers of AS patients (24.8 years) compared with mothers of healthy controls (26.1 years). CONCLUSION: Low birth order is a risk factor for AS in humans.

Adolescent↗