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Biomedical subjects

B W Mol

Publications and source records attributed to B W Mol.

At least 55 records · Page 3Linked to original sources

Treatment of tubal pregnancy in the netherlands: an economic comparison of systemic methotrexate administration and laparoscopic salpingostomy.

OBJECTIVE: This study was undertaken to compare from a societal perspective the costs of systemic methotrexate administration with those of laparoscopic salpingostomy for the treatment of patients with tubal pregnancy. STUDY DESIGN: An economic evaluation was set up in tandem with a multicenter randomized clinical trial that compared systemic methotrexate administration and laparoscopic salpingostomy for the treatment of 100 hemodynamically stable patients with laparoscopically confirmed unruptured tubal pregnancy. Data on resources used for treatment and lost production time were prospectively collected and costs of both treatments were calculated by multiplying actual expenses for resource units at a single center and resource unit use measured in all centers. Costs were originally calculated in Dutch guilders and converted to US dollars at a rate of 1.67 guilders/$1. RESULTS: Because clinical outcomes of the trial were equivalent for the 2 strategies a cost-minimization analysis was done. Mean total costs per patient were $5721 for systemic methotrexate administration and $4066 for laparoscopic salpingostomy, with a mean difference of $1655 (95% confidence interval, $906-$2414). Costs of systemic methotrexate administration were similar to those of salpingostomy for patients in whom the initial serum human chorionic gonadotropin concentration was <1500 IU/L, a cutoff value that had not been previously hypothesized. In a scenario without a confirmatory laparoscopy, in which transvaginal ultrasonography and serial repeated serum human chorionic gonadotropin measurements were assumed to be as accurate as laparoscopy, systemic methotrexate therapy would have reduced total cost by $1500 for a patient with an initial serum human chorionic gonadotropin concentration of <1500 IU/L. In such a scenario total costs would have been similar for a patient with an initial serum human chorionic gonadotropin concentration in the range of 1500 to 3000 IU/L, whereas systemic methotrexate administration would be more costly for a patient with an initial serum human chorionic gonadotropin concentration of >3000 IU/L. CONCLUSIONS: Although systemic methotrexate administration is safe and effective for the treatment of tubal pregnancy, it does not necessarily reduce costs. Systemic methotrexate therapy could reduce costs if administered to patients with low initial serum human chorionic gonadotropin concentrations without confirmatory laparoscopy.

Chorionic Gonadotropin↗

Should patients who are suspected of having an ectopic pregnancy undergo physical examination?

OBJECTIVE: To determine whether physical examination is useful for patients with suspected ectopic pregnancy (EP) for whom transvaginal sonography is performed and serum hCG levels are measured. DESIGN: Prospective study. SETTING: Two large teaching hospitals. PATIENT(S): Three hundred eighty-two patients with suspected EP, based on a positive urine pregnancy test and the presence of abdominal pain, vaginal bleeding, or risk indicators. INTERVENTION(S): Abdominal examination, speculum inspection, and digital vaginal examination. MAIN OUTCOME MEASURE: A final diagnosis made by transvaginal sonography, serum hCG measurement, and, if necessary, confirmatory laparoscopy. RESULT(S): One hundred sixteen (30%) of the 382 patients had an EP. At external abdominal examination, rebound tenderness and muscular rigidity had likelihood ratios of 3.7 and 8.0, respectively. Findings at speculum inspection and digital vaginal examination had likelihood ratios between 0.33 and 2.4. Logistic regression analysis showed that the additional information provided by physical examination for the diagnosis of EP is limited compared with the information provided by transvaginal sonography and serum hCG measurement alone. CONCLUSION: On the basis of our results, we believe that vaginal digital examination for patients with suspected EP is unnecessary.

Adult↗

Can noninvasive diagnostic tools predict tubal rupture or active bleeding in patients with tubal pregnancy?

OBJECTIVE: To evaluate the ability of noninvasive diagnostic tools to predict tubal rupture and active bleeding in patients with tubal pregnancy. DESIGN: Prospective cohort study. SETTING: Two large teaching hospitals in Amsterdam, The Netherlands. PATIENT(S): Consecutively seen patients with suspected tubal pregnancy who were scheduled to undergo confirmative laparoscopy. MAIN OUTCOME MEASURE(S): Tubal rupture and/or active bleeding confirmed at laparoscopy. RESULT(S): Sixty-five (23%) of 288 patients had tubal rupture and/or active bleeding at laparoscopy. Abdominal pain, rebound tenderness on abdominal examination, fluid in the pouch of Douglas at transvaginal ultrasound examination, and a low serum hemoglobin level were independent predictors of tubal rupture and/or active bleeding. Pregnancy achieved with the use of IVF-ET and the presence of an ectopic gestational sac or an ectopic mass at ultrasound examination reduced the risk of tubal rupture. Abdominal pain was the most sensitive predictor, with a sensitivity of 95%. CONCLUSION(S): Because the nonsurgical management of tubal pregnancy should be used only when the risk of tubal rupture and/or active bleeding is low, it can be safely applied in only a limited number of patients.

Adult↗

Are gestational age and endometrial thickness alternatives for serum human chorionic gonadotropin as criteria for the diagnosis of ectopic pregnancy?

OBJECTIVE: To compare gestational age and endometrial stripe thickness measurement with serum hCG measurement as criteria for the diagnosis of ectopic pregnancy (EP). DESIGN: Prospective study. SETTING: Two large teaching hospitals in Amsterdam, The Netherlands. PATIENT(S): Three hundred fifty-four consecutively seen pregnant patients who presented between September 1993 and April 1996 with suspected EP and in whom transvaginal ultrasonogram showed no intrauterine pregnancy or EP. Ultrasonography was performed by one of the study investigators or, during shifts, by the resident on call. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The accuracy of gestational age, endometrial stripe thickness, and serum hCG measurement in the diagnosis of EP was evaluated with receiver operating characteristic curve analysis. RESULT(S): Gestational age and endometrial stripe thickness could not discriminate between patients with EP and patients without EP, whereas serum hCG had an acceptable area under the receiver operating characteristic curve. CONCLUSION(S): Gestational age and endometrial thickness are not useful in the diagnosis of EP. Serum hCG measurement is the diagnostic instrument of choice in patients with suspected EP when transvaginal ultrasonography does not reveal a diagnosis.

Adult↗

Effect of study design on the association between nuchal translucency measurement and Down syndrome.

OBJECTIVE: To evaluate the effect of verification bias on the accuracy of first-trimester nuchal translucency measurement for Down syndrome detection. METHODS: We used MEDLINE and EMBASE to identify all papers relating the results of nuchal translucency measurement to fetal karyotype. The detected studies were scored for verification bias. Fifteen studies without and ten with verification bias were included. RESULTS: Sensitivity and specificity were calculated for each study. For studies with verification bias, adjusted estimates of the sensitivity were calculated assuming a fetal loss rate for Down syndrome pregnancies of 48%. The sample size weighted sensitivity was 55% in studies without and 77% in those with verification bias, for specificities of 96% and 97%, respectively. After adjustment for verification bias, the sample size weighted sensitivity changed from 77% to 63%. CONCLUSION: Studies with verification bias reported higher sensitivities, but also slightly higher specificities of nuchal translucency measurement than studies without verification bias. The difference in sensitivity is greater than could be explained by verification bias. We postulate that the experience of the sonographist might be an explanation for the differences.

Down Syndrome↗

Implementation of probabilistic decision rules improves the predictive values of algorithms in the diagnostic management of ectopic pregnancy.

Current algorithms for the diagnosis of ectopic pregnancy do not take into account the heterogeneity in patient profiles. Such heterogeneity can lead to differences in the pre-test probability of ectopic pregnancy. In patients with clinical symptoms, for example, the probability of presence of an ectopic pregnancy is higher than in symptom-free patients. Any additional tests should then be interpreted differently, depending on the pre-test probability. We present a diagnostic algorithm that uses probabilistic decision rules for the evaluation of women with suspected ectopic pregnancy with flexible cut-off levels for test positivity We compare it with a general algorithm that uses fixed cut-off levels. Fictitious cohorts, varying in prevalence of ectopic pregnancy were put together, using data obtained from a cohort of >800 women with suspected ectopic pregnancy. In the inflexible algorithm, ectopic pregnancy was diagnosed whenever it could be visualized at transvaginal sonography, or where serum human chorionic gonadotrophin (HCG) exceeded a rigid cut-off level; ectopic pregnancy was rejected if an intrauterine pregnancy was seen or when serum HCG decreased. In the flexible algorithm, a post-test probability was obtained after each test, using pre-test probabilities and test-based likelihood ratios. Ectopic pregnancy was diagnosed whenever the post-test probability for ectopic pregnancy exceeded 95%, whereas this diagnosis was rejected if the calculated post-test probability fell below 1%. For both algorithms, sensitivity and specificity as well as predictive values were calculated. At each prevalence, the inflexible algorithm was associated with a sensitivity of 93% and a specificity of 97%. In contrast, the sensitivity and specificity of the flexible, individualized algorithm depended on the prevalence of ectopic pregnancy. Consequently, predictive values varied strongly when the inflexible algorithm was used, whereas they were much more stable after using the flexible algorithm. For five possible valuations of false positive and false negative diagnoses, the flexible algorithm reduced the expected disutility, compared with the inflexible algorithm. It is concluded that clinicians should incorporate probabilistic decision rules in algorithms used for the diagnosis of ectopic pregnancy.

Algorithms↗

How concordant are the estimated rates of natural conception and in-vitro fertilization/embryo transfer success?

Knowledge of the chance to conceive for the subfertile couple is important in the process of counselling and clinical decision making. There are no data available on the reproducibility of the clinician's ability to assess the chance to conceive, both after expectant management or treatment with in-vitro fertilization and embryo transfer (IVF-embryo transfer). We evaluated this reproducibility by means of a set of case histories presented to a panel of gynaecologists and endocrinologists. A poor reproducibility would indicate a strong need for the use of prognostic models. In 1995, 57 gynaecologists and 32 reproductive endocrinologists were asked to appraise the 1 year spontaneous conception chance as well as the cumulative success rate of three cycles for IVF-embryo transfer of four couples with different medical histories. The clinical and laboratory data of these couples were presented as case histories. The difference between the estimated spontaneous pregnancy chances and the success rate of IVF-embryo transfer was also calculated. Calculation of intra-class correlation coefficients, which can be considered as measures of the reproducibility, demonstrated a substantial reproducibility of the assessment of spontaneous conception chances, but a slight to fair reproducibility of the assessment of IVF-embryo transfer success rates. We conclude that the use of reliable prognostic models for IVF-embryo transfer in the management of subfertility is warranted.

Adult↗

Comparison of hysterosalpingography and laparoscopy in predicting fertility outcome.

In this study, we compare the prognostic significance of hysterosalpingography (HSG) and laparoscopy for fertility outcome. In a prospective cohort study in 11 clinics participating in the Canadian Infertility Treatment Evaluation Study (CITES), consecutive couples who registered between 1 April 1984 and 31 March 1987 for the evaluation of subfertility and who underwent HSG and laparoscopy were included. Unilateral and bilateral tubal occlusion at HSG and laparoscopy were related to treatment-independent pregnancy. Cox regression was used to calculate fecundity rate ratios (FRR). Of the 794 patients who were included, 114 (14%) showed one-sided tubal occlusion and 194 (24%) showed two-sided tubal occlusion on HSG. At laparoscopy, 94 (12%) showed one-sided tubal occlusion and 96 (12%) showed two-sided tubal occlusion. Occlusion detected on HSG and laparoscopy showed a moderate agreement beyond chance (weighted kappa-statistic 0.42). The adjusted FRR of one-sided tubal occlusion at HSG was 0.80, whereas two-sided tubal occlusion showed an FRR of 0.49. For laparoscopy, the FRR were 0.51 and 0.15 respectively. After a normal or one-sided occluded HSG, laparoscopy showed two-sided occlusion in 5% of the patients, and fertility prospects in these patients were virtually zero. If two-sided tubal occlusion was detected on HSG but not during laparoscopy, fertility prospects were slightly impaired. Fertility prospects after a two-sided occluded HSG were strongly impaired in cases where laparoscopy showed one-sided and two-sided occlusion, with FRR of 0.38 and 0.19 respectively. Although laparoscopy performed better than HSG as a predictor of future fertility, it should not be considered as the perfect test in the diagnosis of tubal pathology. For clinical practice, laparoscopy can be delayed after normal HSG for at least 10 months, since the probability that laparoscopy will show tubal occlusion after a normal HSG is very low.

Adult↗

Use of the disutility ratio in prenatal screening for Down's syndrome.

OBJECTIVE: To assess the value of the triple test incorporating individual differences in parental evaluation of outcomes of pregnancy. DESIGN: Decision analysis. SAMPLE: Monte Carlo simulation of triple test results in 25,000 women with a normal pregnancy and 25,000 women with a pregnancy affected by Down's syndrome. METHODS: A decision model was developed for women who were 16 weeks pregnant. Three strategies were evaluated: 1. no prenatal testing; 2. amniocentesis; and 3. the triple test followed by amniocentesis if the risk of a pregnancy with Down's syndrome, based on maternal age and the triple test results (post-test risk), was above the woman's threshold risk for amniocentesis. MAIN OUTCOME MEASURES: The outcomes considered were: 1. birth of a child without Down's syndrome; 2. birth of a child with Down's syndrome; and 3. pregnancy loss, either spontaneously, or as a result of termination. The values of these pregnancy outcomes were expressed on a disutility scale in units of 'lost pregnancy equivalents'. The birth of a normal child brings no disutility. The disutility of the birth of a child with Down's syndrome is consequently specified by the ratio of the expected parental distress after the birth of a child with Down's syndrome to the expected parental distress after the loss of the pregnancy (disutility ratio). RESULTS: The value of the triple test depends strongly on maternal age as well as on the individual evaluation of the outcome of pregnancy. The triple test is of considerable value for all women > 38 years; its value for women between 27 and 38 years depends on the disutility ratio, and it is of little value for women < 27 years. CONCLUSION: The value of the triple test depends on the parental evaluation of outcome of pregnancy for a large group of pregnant women. The disutility ratio, as introduced in this study, might be an instrument to elicit these values for individual women in clinical practice.

Abortion, Induced↗

Nifedipine versus ritodrine for suppression of preterm labor; a meta-analysis.

BACKGROUND: Since large randomized clinical trials comparing the effectiveness of nifedipine and ritodrine in the suppression of preterm labor are lacking, we performed a meta-analysis on the subject. METHODS: We searched the databases Medline and EMBASE using the keywords 'nifedipine', 'ritodrine' and 'randomized' or 'randomised'. The studies were scored for blinding, method of randomization and type of analysis ('intention-to-treat' versus 'par protocol'). Subsequently, two by two tables were constructed using 'delay of labor by 48 hours or more', 'delay of labor beyond 36 weeks gestation', perinatal mortality, respiratory distress syndrome and admission to a neonatal intensive care unit as end points. Homogeneity between the studies was tested with a Breslow-Day test. Pooled odds ratios were calculated in case homogeneity could not be rejected. RESULTS: We could detect ten studies that were published between 1986 and 1998, incorporating data of 681 patients. Nifedipine reduced the risk of delivery within 48 hours compared to ritodrine, but this difference was not statistically significant (odds ratio 0.85, 95% confidence interval 0.54 to 1.1). Nifedipine also reduced the risk of delivery before 36 weeks compared to ritodrine, and this difference was statistically significant (odds ratio 0.59, 95% confidence interval 0.39 to 0.90). We are not aware of studies reporting on long-term outcome. CONCLUSION: Since studies reporting on long-term outcome are lacking, the choice between nifedipine and ritodrine can only be based on obstetrical and short-term neonatal outcomes. From that perspective, nifedipine should be the drug of first choice for the suppression of preterm labor.

Female↗

Prognostic significance of diagnostic laparoscopy for spontaneous fertility.

OBJECTIVE: To determine the prognostic significance of laparoscopy results for fertility outcome. STUDY DESIGN: Consecutive patients undergoing hysterosalpingography and laparoscopy for subfertility in our department between May 1985 and November 1987 were identified from medical records. The impact of tubal occlusion, hydrosalpinx and adhesions as detected at laparoscopy was studied. Kaplan-Meier curves for the occurrence of spontaneous intrauterine pregnancy were constructed for patients without tubal pathology, with mild tubal pathology (unilateral pathology or adhesions) and with severe tubal pathology (bilateral pathology). Fecundity rate ratios (FRR) were calculated to express the association between findings at laparoscopy and the occurrence of spontaneous intrauterine pregnancy. RESULTS: Of the 200 cases that could be analyzed, 129 (65%) showed no tubal occlusion on laparoscopy, 40 (20%) had unilateral tubal occlusion, and 31 (15%) had bilateral tubal occlusion. Unilateral hydrosalpinx was present in 13 (7%) patients, whereas 19 (10%) patients had bilateral hydrosalpinx. Adjusted FRRs were 0.65 and 0.20 for unilateral and bilateral tubal occlusion, and 0.46 and 0.32 for unilateral and bilateral hydrosalpinx. Peritubal adhesions were detected in 43% of patients and seemed to have no prognostic significance. CONCLUSION: Severe tubal pathology detected at laparoscopy affects fertility prospects strongly. However, since spontaneous intrauterine pregnancies occurred even in patients with bilateral tubal occlusion at laparoscopy, this technique should not be considered the gold standard in the diagnosis of tubal infertility.

Adult↗

[Roaming through methodology. X. The testing of diagnostic procedures].

In this era of evidence-based medicine, diagnostic tests cannot escape close scrutiny of their effectiveness. Sensitivity and specificity have up till now played a central role in the evaluation of diagnostic tests. These terms are not without their shortcomings when it comes to the characterisation of a test's true worth for patients. Randomised clinical trials are increasingly used for evaluation of medical tests and outlining of strategy. The indirect relationship between test results and health outcome creates additional challenges for designers of such trials.

Diagnostic Techniques and Procedures↗