A G H Kessels

Maastricht University, Maastricht, Provincie Limburg, Netherlands

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Publications (43)108.83 Total impact

  • Article: Association between guideline adherence and clinical outcome for patients referred for diagnostic breast imaging.
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    ABSTRACT: To assess the adherence to a guideline for additional breast ultrasonography in a cross-sectional survey among hospitals in The Netherlands. Furthermore, consequences of current practice non-adherence for the patient outcome of diagnostic breast imaging were studied. Current practice was compared with a guideline made up of three recommendations for the use of ultrasonography after mammography and three recommendations for not using ultrasonography. All patients referred for mammography to the radiology departments of the participating hospitals during 2 months in 2004 were eligible for the study. No data on the gold standard for breast cancer were analysed, but clinical consequences were estimated by using a probability model based on the data of a former prospective clinical study. In total, 17 of the 66 hospitals approached were participating in the study. Of the 13,694 patients assessed for eligibility, 6457 were included. High adherence rates (81-97%, mean 94%) were observed for the recommendations, which indicate additional ultrasonography, whereas lower adherence rates (68-94%, mean 83%) were seen for the recommendations which do not advise additional ultrasonography. Overall, in all included hospitals, non-adherence would result in 27.2 false-positive and 1.1 false-negative imaging results. Current daily practice of diagnostic breast imaging in the hospitals in this survey corresponds to a great extent to the guideline proposed. Non-adherence in current practice results in a relatively small number of false-positive and false-negative imaging results.
    Quality and Safety in Health Care 12/2010; 19(6):503-8. · 1.68 Impact Factor
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    Article: A patient-centred instrument for assessment of quality of breast cancer care: results of a pilot questionnaire.
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    ABSTRACT: In several breast cancer research environments, there was a need to develop a questionnaire that would (1) provide data on how breast cancer patients experience healthcare services, (2) address issues corresponding with patients' needs and expectations and (3) produce useful data for quality assessment and improvement projects aimed at breast cancer care. This article describes the first part of the quantitative process of item selection, instrument construction and optimisation based on the results of a pilot questionnaire. Based on qualitative research, a pilot questionnaire with items formulated as "performance" and "importance" statements was developed and sent to all breast cancer patients operated on in the previous 3-15 months in five participating hospitals. Reduction criteria, exploratory factor analysis and reliability analysis were used as part of the process of instrument optimisation. Of the 637 questionnaires sent out, 299 (47%) were returned and 276 (43%) were used for analyses. Out of the 72 quality items included in the pilot questionnaire, 42 items did not meet the inclusion criteria for the revised version. The remaining items refer to the factors patient education regarding aspects related to postoperative treatment, services by the breast nurse, services by the surgeon, patient education regarding activities at home and patient education regarding aspects related to preoperative treatment (Cronbach α = 0.70-0.89). In this study, the number of items to be included in the self-administered questionnaire was reduced. The resulting set of items that determines patients' perceptions on quality of breast cancer care is easy to complete and enables anonymous responses. Further research can be aimed at establishing the reliability of the current questionnaire.
    Quality and Safety in Health Care 12/2010; 19(6):e40. · 1.68 Impact Factor
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    Article: Patients' opinions on quality of care before and after implementation of a short stay programme following breast cancer surgery.
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    ABSTRACT: To assess breast cancer patients' opinions on quality of care during an implementation study on short hospital stay, and to formulate patient inspired targets for further quality improvement based on results of the QUOTE (Quality of Care Through the Patients' Eyes) breast cancer instrument. Quality of patient education regarding activities at home was in need of improvement in both measurements. Quality of services delivered by the surgeon improved somewhat after implementation. Although quality of waiting and process times improved after implementation, there was still room for further improvement on these aspects. A breast cancer care programme in short stay was introduced while, on average, preserving quality of care as perceived by the patient. However, aspects regarding education on drains, prosthesis, exercises after surgery, survival rates, and waiting and process times require continuing attention to enhance patients' assessment of quality of care.
    Breast (Edinburgh, Scotland) 05/2010; 19(5):404-9. · 2.09 Impact Factor
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    Article: Diagnostic performance of breast technologists in reading mammograms in a clinical patient population.
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    ABSTRACT: In the setting of an increasing workload for radiologists, this study focuses on the feasibility of skill mixing in breast imaging in a hospital radiology department. Two radiological technologists with more than 10 years of experience in performing mammograms were trained in prereading mammograms to select the cases that require further evaluation by a radiologist. Mammograms of consecutive patients were independently evaluated by the technologists, next to the standard clinical interpretation by the radiologist on duty. Mammographic findings were recorded and a BI-RADS classification was assigned for each breast. Different prereading scenarios were analysed using clinical decision rules. Two different cut-off points of BI-RADS classifications were applied to the data. Analysis was performed for the overall clinical patient population as well as for a subgroup of patients with no immediate indication for further work-up. Mammograms of 1994 patients were evaluated. In total, 93 breast cancers were found in 91 patients (prevalence 4.6%). Sensitivity and specificity in selecting mammographic findings (cut-off point between BI-RADS 1 and BI-RADS 0, 2-5 and the radiologist's diagnosis as reference standard) was 98% and 74% for technologist 1 and 98% and 78% for technologist 2. In distinguishing normal and benign mammograms from those with abnormalities that are probably benign, suspicious or highly suggestive for malignancy (cut-off point BI-RADS 1-2 and BI-RADS 0, 3-5 and pathology results as reference standard), sensitivity decreased to 89% and 91% respectively. Specificity increased to 82% for both technologists. In a subgroup of 1389 patients with no immediate indication for additional imaging with the involvement of a radiologist, technologists obtained a mean sensitivity and specificity of 98% and 77% in detecting mammographic findings, and a mean sensitivity and specificity of 78% and 88% in detecting suspicious abnormalities. The employment of technologists in prereading mammograms seems to be an effective working strategy in daily clinical practice. However, its position in clinical practice remains indistinct as a continuous availability of radiologists still needs to be guaranteed. Nevertheless, as a substantial proportion of mammograms could be evaluated without the attention of a radiologist, the employment of technologists in prereading mammograms seems a promising new working strategy.
    International Journal of Clinical Practice 03/2010; 64(4):442-50. · 2.41 Impact Factor
  • Article: Local recurrence in rectal cancer can be predicted by histopathological factors.
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    ABSTRACT: The main cause of local recurrence (LR) in rectal cancer is involvement of the circumferential resection margin (CRM). However, patients with a negative CRM can also develop LR, suggesting that additional factors are important for LR. The aim of this study was to identify histopathological factors predictive for the development of LR after primary rectal cancer treatment. T x N x M0 patients treated for locally recurrent rectal cancer at the Catharina hospital from 1994 to 2006 (n=92) were matched with a control group of patients who did not develop LR after primary rectal cancer treatment for at least 2 years (n=185) based on the type of neoadjuvant treatment in a 1:2 ratio. The pathology of all primary rectal cancers was reviewed. Patient, treatment and histopathological characteristics were studied in relation to the development of LR with logistic regression. Logistic regression indicated the presence of lymphovascular invasion (LVI, OR 4.66, P<0.001), extramural venous invasion (EMVI, OR 4.54, P<0.001), positive CRM (OR 2.56, P=0.032), serosal involvement (OR 6.74, P=0.035) and poor differentiation (OR 2.59, P=0.012) as factors with an increased risk to develop LR. Older age was a protective factor (OR 0.95, CI 0.93-0.98, P=0.001). Apart from a positive CRM and serosal involvement, LVI, EMVI and poor differentiation are important independent predictive factors for the development of LR. Adjuvant therapy may be considered in the presence of these features in order to decrease the risk of a local recurrence.
    European journal of surgical oncology: the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology 04/2009; 35(10):1071-7. · 2.56 Impact Factor
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    Article: Vascular calcifications as a marker of increased cardiovascular risk: a meta-analysis.
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    ABSTRACT: Several imaging techniques may reveal calcification of the arterial wall or cardiac valves. Many studies indicate that the risk for cardiovascular disease is increased when calcification is present. Recent meta-analyses on coronary calcification and cardiovascular risk may be confounded by indication. Therefore, this meta-analysis was performed with extensive subgroup analysis to assess the overall cardiovascular risk of finding calcification in any arterial wall or cardiac valve when using different imaging techniques. A meta-analysis of prospective studies reporting calcifications and cardiovascular end-points was performed. Thirty articles were selected. The overall odds ratios (95% confidence interval [CI]) for calcifications versus no calcifications in 218,080 subjects after a mean follow-up of 10.1 years amounted to 4.62 (CI 2.24 to 9.53) for all cause mortality, 3.94 (CI 2.39 to 6.50) for cardiovascular mortality, 3.74 (CI 2.56 to 5.45) for coronary events, 2.21 (CI 1.81 to 2.69) for stroke, and 3.41 (CI 2.71 to 4.30) for any cardiovascular event. Heterogeneity was largely explained by length of follow up and sort of imaging technique. Subgroup analysis of patients with end stage renal disease revealed a much higher odds ratio for any event of 6.22 (CI 2.73 to 14.14). The presence of calcification in any arterial wall is associated with a 3-4-fold higher risk for mortality and cardiovascular events. Interpretation of the pooled estimates has to be done with caution because of heterogeneity across studies.
    Vascular Health and Risk Management 02/2009; 5(1):185-97.
  • Article: To eat or not to eat: facilitating early oral intake after elective colonic surgery in the Netherlands.
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    ABSTRACT: It was shown that patients in the Netherlands remain exposed to unnecessarily prolonged starvation after abdominal surgery. The present study examined whether a structured collaborative effort would help to implement the early start of oral nutrition after colorectal surgery. In 2006, twenty-six Dutch hospitals signed up to a "breakthrough project" concerning the implementation of the enhanced recovery after surgery (ERAS) programme with early oral feeding as one of the key elements. Each hospital determined the usual start of food intake by analyzing 50 patients who underwent a colorectal resection in 2004 (n=1126). Subsequently, over the course of one year 861 colorectal surgery patients were treated according to the ERAS programme. The first day that patients were eating before and after the breakthrough project was compared using Kaplan-Meier analyses and Cox regression models. Patients treated according to the ERAS programme were eating 3 days earlier than the patients traditionally treated (p<0.000). Two days after surgery 65% of the ERAS patients were eating normal food versus 7% of the pre-ERAS patients. The present nationwide collaborative effort was successful in implementing a change towards an early start of oral nutrition after abdominal surgery.
    Clinical nutrition (Edinburgh, Scotland) 01/2009; 28(1):29-33. · 3.27 Impact Factor
  • Article: Screening strategies for tubal factor subfertility.
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    ABSTRACT: Different screening strategies exist to estimate the risk of tubal factor subfertility, preceding laparoscopy. Three screening strategies, comprising Chlamydia trachomatis IgG antibody testing (CAT), high-sensitivity C-reactive protein (hs-CRP) testing and hysterosalpingography (HSG), were explored using laparoscopy as reference standard and the occurrence of a spontaneous pregnancy as a surrogate marker for the absence of tubal pathology. In this observational study, 642 subfertile women, who underwent tubal testing, participated. Data on serological testing, HSG, laparoscopy and interval conception were collected. Multiple imputations were used to compensate for missing data. Strategy A (HSG) has limited value in estimating the risk of tubal pathology. Strategy B (CAT-->HSG) shows that CAT significantly discerns patients with a high versus low risk of tubal pathology, whereas HSG following CAT has no additional value. Strategy C (CAT-->hs-CRP-->HSG) demonstrates that hs-CRP may be valuable in CAT-positive patients only and HSG has no additional value. CAT is proposed as first screening test for tubal factor subfertility. In CAT-negative women, HSG may be performed because of its high specificity and fertility-enhancing effect. In CAT-positive women, hs-CRP seems promising, whereas HSG has no additional value. The position and timing of laparoscopy deserves critical reappraisal.
    Human Reproduction 08/2008; 23(8):1840-8. · 4.47 Impact Factor
  • Article: Location of involved mesorectal and extramesorectal lymph nodes in patients with primary rectal cancer: preoperative assessment with MR imaging.
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    ABSTRACT: The purpose of this study is to evaluate the location of involved mesorectal and extramesorectal lymph nodes as depicted on preoperative MRI. Preoperative availability of this information might be useful for the surgeon as well as the radiation therapist and medical oncologist for optimal treatment strategy: type and extent of neoadjuvant treatment as well as extent of surgical resection. Forty-one patients with biopsy-proven rectal cancer were included. All patients underwent preoperative MRI using USPIO (lymph node specific contrast agent). Location of all mesorectal and extramesorectal nodes visible on MRI was recorded, as well as USPIO prediction on nodal status. Lesion-by-lesion analysis using histology after surgery was performed for patients who did not receive long course chemoradiation therapy. There were 438 nodes visible, 94 of which were malignant. Most nodes are located in the laterodorsal part of the mesorectum, with no difference in distribution between positive and negative nodes. In relation to height of tumor, the majority of positive nodes are located at tumor height or above. There were significantly more negative nodes (9.6%) located below tumor height as compared to positive nodes (2.1%). There were 40 extramesorectal nodes, in 16 patients, 5 of which were positive in 4 patients. All patients had distal rectal cancer. In conclusion, positive mesorectal nodes are located in the laterodorsal part of the mesorectum, at tumor height or above. Positive nodes distal to the tumor are rare, and occur in patients with more proximal nodal metastases. Positive extramesorectal nodes mainly occur in patients with distal rectal cancer with nodal metastases in the mesorectum.
    European journal of surgical oncology: the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology 08/2008; 34(7):776-81. · 2.56 Impact Factor
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    Article: Length of stay: an inappropriate readout of the success of enhanced recovery programs.
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    ABSTRACT: Enhanced recovery after surgery (ERAS) programs are designed to reduce hospital length of stay by shortening the postoperative recovery period. The intended effect of an accelerated recovery on the length of stay may be frustrated by a delayed discharge. This study was designed to assess the influence of an ERAS program on the proportion, appropriateness, and extent of delay in discharge. Patients who enrolled in the ERAS program (n = 121) between 2003 and 2006 were compared with 52 patients who were managed traditionally in 2001. Ninety percent of the pre-ERAS patients and 87% of the ERAS patients were not discharged on the day that discharge criteria were fulfilled. The additional stay of 59% of the pre-ERAS patients and 69% of the ERAS patients was inappropriate. Wound care (15% in the pre-ERAS and 3% of the ERAS group) and observation of any symptoms pointing to an anastomotic leakage (10% in both groups) were the most important reasons for a medical appropriate delay of discharge. The extent of delay in discharge decreased significantly from a median of two days in the pre-ERAS group to a median of 1 day in the ERAS group (p = 0.004). Reductions in length of stay up to a median of 2 days after start of an enhanced recovery program may relate to changes in organization of care and not to a shorter recovery period. Recovery statistics should replace or at least be added to the length of stay as outcome of enhanced recovery programs.
    World Journal of Surgery 07/2008; 32(6):971-5. · 2.36 Impact Factor
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    Article: Prospective evaluation of ischemia in brachial-basilic and forearm prosthetic arteriovenous fistulas for hemodialysis.
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    ABSTRACT: Ischemia is a devastating complication after arteriovenous fistula (AVF) creation. When not timely corrected, it may lead to amputation. Symptomatic ischemia occurs in 3.7-5% of the hemodialysis population. Upper arm AVFs have a higher incidence of ischemia compared to forearm AVFs. As more patients may need upper arm AVFs in the growing and older hemodialysis population, occurrence of symptomatic ischemia may increase. The purpose of this study is to identify predictors for occurrence of ischemia. A prospective evaluation of ischemia was performed in patients randomised for either a brachial-basilic (BB-) AVF or a prosthetic forearm loop AVF. Clinical parameters, preoperative vessel diameters, access flows, digital blood pressures, digit-to-brachial indices (DBI) and interventions for ischemia were recorded. Sixty-one patients (BB-AVF 28) were studied. Seventeen patients (BB-AVF 8) developed ischemic symptoms. Six patients (BB-AVF 3) needed interventions for severe symptoms. Age, history of peripheral arterial reconstruction and radial artery volume flow were significant predictors for the occurrence of ischemia. Symptomatic ischemia occurred in 28% of patients with brachial-basilic and prosthetic forearm AVFs. Age, history of peripheral arterial reconstruction and radial artery volume flow might be important for prediction of ischemia.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 06/2008; 35(5):619-24. · 2.92 Impact Factor
  • Article: The prevalence of postoperative pain in a sample of 1490 surgical inpatients.
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    ABSTRACT: To measure the prevalence of postoperative pain, an assessment was made of 1490 surgical inpatients who were receiving postoperative pain treatment according to an acute pain protocol. Measurements of pain (scores from 0 to 100 on a visual analogue scale) were obtained three times a day on the day before surgery and on days 0-4 postoperatively; mean pain intensity scores were calculated. Patients were classified as having no pain (score 0-5), mild pain (score 6-40), moderate pain (score 41-74) or severe pain (score 75-100). Moderate or severe pain was reported by 41% of the patients on day 0, 30% on days 1 and 19%, 16% and 14% on days 2, 3 and 4. The prevalence of moderate or severe pain in the abdominal surgery group was high on postoperative days 0-1 (30-55%). A high prevalence of moderate or severe pain was found during the whole of days 1-4 in the extremity surgery group (20-71%) and in the back/spinal surgery group (30-64%). We conclude that despite an acute pain protocol, postoperative pain treatment was unsatisfactory, especially after intermediate and major surgical procedures on an extremity or on the spine.
    European Journal of Anaesthesiology 05/2008; 25(4):267-74. · 2.23 Impact Factor
  • Article: [Peripheral artery disease: clinical and cost comparison between duplex ultrasonography and contrast-enhanced magnetic resonance angiography--a multicenter randomized trial].
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    ABSTRACT: To determine the clinical and economic consequences of replacing duplex ultrasonography (DUS) by contrast-enhanced magnetic resonance angiography (CE-MRA) for the initial diagnostic work-up of patients with peripheral artery disease (PAD). Randomised multicentre study. In the period from January 2002 to August 2003, consecutive patients with PAD were randomly assigned to CE-MRA or DUS. The primary outcome measure was the costs. Secondary outcome measures included the confidence with which the specialist could take a therapeutic decision on the basis of the imaging study, the change in disease severity, and the change in quality of life (QOL) assessed during 6 months of follow-up. In addition, all costs of imaging, therapeutic interventions and outpatient visits were calculated. After 6 months of follow-up the data on 352 patients were analysed. Use of CE-MRA reduced the number of additional vascular-imaging procedures by 42% ((69-40)/69) and the specialists felt more confident about their therapeutic decisions. The diagnostic costs of all imaging studies taken together were Euro 167,- higher, on average, in the CE-MRA group (p < 0.001). However, after 6 months of follow-up, no statistically significant differences were found between the two groups with regard to the change in disease severity, the QOL, or the total costs (p > 0.05). Based on these findings, a specialist that replaces DUS by CE-MRA will feel more confident about taking a therapeutic decision and will feel less need for additional imaging. However, the diagnostic costs were higher with CE-MRA.
    Nederlands tijdschrift voor geneeskunde 08/2007; 151(32):1789-94.
  • Article: A protocol is not enough to implement an enhanced recovery programme for colorectal resection.
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    ABSTRACT: Single-centre studies have suggested that enhanced recovery can be achieved with multimodal perioperative care protocols. This international observational study evaluated the implementation of an enhanced recovery programme in five European centres and examined the determinants affecting recovery and length of hospital stay. Four hundred and twenty-five consecutive patients undergoing elective open colorectal resection above the peritoneal reflection between January 2001 and January 2004 were enrolled in a protocol that defined multiple perioperative care elements. One centre had been developing multimodal perioperative care for 10 years, whereas the other four had previously undertaken traditional care. The case mix was similar between centres. Protocol compliance before and during the surgical procedure was high, but it was low in the immediate postoperative phase. Patients fulfilled predetermined recovery criteria a median of 3 days after operation but were actually discharged a median of 5 days after surgery. Delay in discharge and the development of major complications prolonged length of stay. Previous experience with fast-track surgery was associated with a shorter hospital stay. Functional recovery in 3 days after colorectal resection could be achieved in daily practice. A protocol is not enough to enable discharge of patients on the day of functional recovery; more experience and better organization of care may be required.
    British Journal of Surgery 03/2007; 94(2):224-31. · 4.61 Impact Factor
  • Article: C-reactive protein, atherosclerosis and kidney function in hypertensive patients.
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    ABSTRACT: Previous studies have shown a relationship between coronary or carotid atherosclerosis and C-reactive protein (CRP) concentrations. In the present investigation, we evaluated the relationship between high-sensitivity CRP (hsCRP) concentrations and the presence of atherosclerotic lesions in the renal arteries and/or abdominal aorta. In 95 hypertensive patients who underwent intra-arterial DSA on suspicion of renovascular disease, blood was sampled during the procedure for measurement of hsCRP. The presence of atherosclerotic lesions was assessed at the level of the renal arteries and the abdominal aorta. Haemodynamically significant renal artery stenosis was diagnosed when 50% or more stenosis was observed. Patients with fibromuscular disease (n = 8) or incomplete data (n = 4) were excluded from analysis. The results revealed that the median hsCRP concentrations were significantly higher among the 57 patients with atherosclerosis of the aorta and/or renal arteries compared to those in the 26 patients without any angiographic lesions (4.6 vs 1.7 mg/l; P < 0.005). Moreover, in patients with renal artery stenosis, levels of hsCRP were higher when the degree of stenosis exceeded 50%. However, the association between hsCRP and the presence of atherosclerosis appeared to be confounded by serum creatinine, creatinine clearance, age and gender. In the whole group a significant inverse relationship was found between creatinine clearance and hsCRP (P < 0.05). In conclusion, hsCRP concentrations are related to atherosclerotic lesions in the renal arteries and the abdominal aorta. While this supports the view that atherosclerotic renal artery stenosis is part of a systemic inflammatory vascular disease, increased concentrations of CRP may also coincide with decreased renal function.
    Journal of Human Hypertension 08/2005; 19(7):521-6. · 2.80 Impact Factor
  • Article: Serological markers of persistent C. trachomatis infections in women with tubal factor subfertility.
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    ABSTRACT: Persistent C. trachomatis infections are assumed to increase the risk of tubal pathology. We studied whether serological markers, assumed to be associated with persistent C. trachomatis infections, could identify subfertile women at risk of tubal pathology. Sera of 313 subfertile women, who all underwent a laparoscopy with tubal testing to assess the grade of tubal pathology, were tested for the presence of immunoglobulin (Ig) G and IgA antibodies to C. trachomatis, IgG antibodies to chlamydia heat shock protein 60 (cHSP60) and C-reactive protein (CRP). C. trachomatis IgA, cHSP60 IgG and CRP, all serological markers of persistent infections, were significantly more prevalent in women with tubal pathology as compared to those without tubal pathology. The predictive value of the currently used screening test for tubal pathology (IgG to C. trachomatis) could be significantly improved by adding the CRP test. In subfertile women with tubal pathology, serological markers of persistent C. trachomatis infections are significantly more common as compared to women without tubal pathology. C. trachomatis IgG-positive subfertile women with slightly elevated (< 10 mg/l) CRP levels are at highest risk of persistent C. trachomatis infections and tubal pathology.
    Human Reproduction 05/2005; 20(4):986-90. · 4.47 Impact Factor
  • Article: Comparison of randomization techniques for clinical trials with data from the HOMERUS-trial.
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    ABSTRACT: Several methods of randomization are available to create comparable intervention groups in a study. In the HOMERUS-trial, we compared the minimization procedure with a stratified and a non-stratified method of randomization in order to test which one is most appropriate for use in clinical hypertension trials. A second objective of this article was to describe the baseline characteristics of the HOMERUS-trial. The HOMERUS population consisted of 459 mild-to-moderate hypertensive subjects (54% males) with a mean age of 55 years. These patients were prospectively randomized with the minimization method to either the office pressure (OP) group, where antihypertensive treatment was based on office blood pressure (BP) values, or to the self-pressure (SP) group, where treatment was based on self-measured BP values. Minimization was compared with two other randomization methods, which were performed post-hoc: (i) non-stratified randomization with four permuted blocks, and (ii) stratified randomization with four permuted blocks and 16 strata. In addition, several factors that could influence outcome were investigated for their effect on BP by 24-h ambulatory blood pressure monitoring (ABPM). Minimization and stratified randomization did not lead to significant differences in 24-h ABPM values between the two treatment groups. Non-stratified randomization resulted in a significant difference in 24-h diastolic ABPM between the groups. Factors that caused significant differences in 24-h ABPM values were: region, centre of patient recruitment, age, gender, microalbuminuria, left ventricular hypertrophy and obesity. Minimization and stratified randomization are appropriate methods for use in clinical trials. Many outcome factors should be taken into account for their potential influence on BP levels. Recommendation. Due to the large number of potential outcome factors that can influence BP levels, minimization should be the preferred method for use in clinical hypertension trials, as it has the potential to randomize more outcome factors than stratified randomization.
    Blood Pressure 02/2005; 14(5):306-14. · 1.43 Impact Factor
  • Article: Cost-effectiveness of Chlamydia antibody tests in subfertile women.
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    ABSTRACT: For the evaluation of tubal function, Chlamydia antibody testing (CAT) has been introduced as a screening test. We compared six CAT screening strategies (five CAT tests and one combination of tests), with respect to their cost-effectiveness, by using IVF pregnancy rate as outcome measure. A decision analytic model was developed based on a source population of 1715 subfertile women. The model incorporates hysterosalpingography (HSG), laparoscopy and IVF. To calculate IVF pregnancy rates, costs, effects, cost-effectiveness and incremental costs per effect of the six different CAT screening strategies were determined. pELISA Medac turned out to be the most cost-effective CAT screening strategy (15 075 per IVF pregnancy), followed by MIF Anilabsystems (15 108). A combination of tests (pELISA Medac and MIF Anilabsystems; 15 127) did not improve the cost-effectiveness of the single strategies. Sensitivity analyses showed that the results are robust for changes in the baseline values of the model parameters. Only small differences were found between the screening strategies regarding the cost-effectiveness, although pELISA Medac was the most cost-effective strategy. Before introducing a particular CAT test into clinical practice, one should consider the effects and consequences of the entire screening strategy, instead of only the diagnostic accuracy of the test used.
    Human Reproduction 02/2005; 20(2):425-32. · 4.47 Impact Factor
  • Article: A needle-localised open-breast biopsy for nonpalpable breast lesions should not be performed for diagnosis.
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    ABSTRACT: The achievement of tumour-free margins on excision of nonpalpable breast lesions that have aroused only an intermediate or low level of suspicion before surgery and do turn out to be malignant is a challenge for the surgeon. The purpose of this study was to determine factors that influence the probability of obtaining tumour-free margins after needle-localised excision of a nonpalpable breast carcinoma. During a 10-year period all needle-localised breast biopsies (NLBB) carried out in the Department of Surgery were retrospectively analysed. Possible influential factors considered included: age of the patient, year of NLBB, appearance of the lesion on imaging, preoperative diagnostic index, method of localisation, surgeon's level of experience, specimen size and radiology of the specimen, and all these were analysed in a multivariate logistic regression analysis. In all, 400 needle-localised breast biopsies had been performed. Excision with tumour-free margins was more often achieved, and the final intervention less often took the form of a mastectomy, when the lesion was classified preoperatively as malignant (P = 0.02). The outcome of treatment of a needle-localised breast cancer excision is better when the breast lesion is known to be malignant before surgery.
    The Breast 01/2005; 13(6):476-82. · 2.49 Impact Factor
  • Article: Psychological characteristics of patients with newly developed psychogenic seizures.
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    ABSTRACT: To assess psychopathological symptoms and history of childhood trauma in patients with newly developed psychogenic seizures. Using validated scales, 178 patients from the general population diagnosed with newly developed seizures were assessed, at a point in time when the nature of their seizures was yet unknown to either doctors or patients. After standardised neurological examination, 138 patients were diagnosed with non-psychogenic seizures (NPS), while 40 patients were found to have psychogenic seizures (PS). To evaluate possible differences between the genders and the diagnostic groups, univariate analyses of variance were done. PS patients reported significantly more comorbid psychopathological complaints, dissociative experiences, anxiety, and self-reported childhood trauma than NPS patients. In addition, PS patients had lower quality of life ratings than NPS patients. These effects were not modulated by gender. The results of the present study indicate that patients with newly developed PS constitute a group with complex psychopathological features that warrant early detection and treatment.
    Journal of Neurology Neurosurgery &amp Psychiatry 09/2004; 75(8):1175-7. · 4.76 Impact Factor