[Stability of high-dose etoposide dilutions for use in hematopoietic stem cell transplantation conditioning regimens]. / Stabilité d'une dose élevée d'étoposide en dilution pour utilisation lors du conditionnement avant greffe de cellules souches.

High-dose etoposide is used in conditioning regimens for allogeneic stem cell transplantation. The limited stability of the drug induces barriers for its use for pharmacists, nurses and patients. When using a concentration of 10 mg/mL etoposide in physiologic saline, limitations can be overcome. This study provides stability data for etoposide in a high concentration that can be used in conditioning regimens. The solution was stable for 48h at 5°C, for 48h at 5°C followed by 8h at 25°C and for 24 h at 25°C.

Experience with multiple control groups in a large population-based case-control study on genetic and environmental risk factors.

We discuss the analytic and practical considerations in a large case-control study that had two control groups; the first control group consisting of partners of patients and the second obtained by random digit dialling (RDD). As an example of the evaluation of a general lifestyle factor, we present body mass index (BMI). Both control groups had lower BMIs than the patients. The distribution in the partner controls was closer to that of the patients, likely due to similar lifestyles. A statistical approach was used to pool the results of both analyses, wherein partners were analyzed with a matched analysis, while RDDs were analyzed without matching. Even with a matched analysis, the odds ratio with partner controls remained closer to unity than with RDD controls, which is probably due to unmeasured confounders in the comparison with the random controls as well as intermediary factors. However, when studying injuries as a risk factor, the odds ratio remained higher with partner control subjects than with RRD control subjects, even after taking the matching into account. Finally we used factor V Leiden as an example of a genetic risk factor. The frequencies of factor V Leiden were identical in both control groups, indicating that for the analyses of this genetic risk factor the two control groups could be combined in a single unmatched analysis. In conclusion, the effect measures with the two control groups were in the same direction, and of the same order of magnitude. Moreover, it was not always the same control group that produced the higher or lower estimates, and a matched analysis did not remedy the differences. Our experience with the intricacies of dealing with two control groups may be useful to others when thinking about an optimal research design or the best statistical approach.

The risk for breast cancer is not evidently increased in women with hyperprolactinemia.

The question has been raised whether hyperprolactinemia in humans is associated with an excess risk for breast cancer. We aimed to assess the risk of breast cancer in a previously defined large cohort of patients treated for idiopathic hyperprolactinemia or prolactinomas. Based on the pattern of drug prescriptions we identified 11,314 subjects in the PHARMO network with at least one dispensing of dopamine agonists between 1996 and 2006. Of these, 1,607 subjects were considered to have dopamine agonist-treated hyperprolactinemia based on the prescribing pattern. For the present analysis, we included only women (n = 1,342). Patients with breast cancer were identified by hospital discharge codes. Data on breast cancer incidence in the Netherlands were derived from the Dutch cancer registry. Standardized mortality ratio (SMR) was the measure of outcome to assess the association between hyperprolactinemia and breast cancer. The 1,342 patients accounted for a total of 6,576 person years. Eight patients with breast cancer during follow-up were identified. Indirect standardization with incidence proportions from the general Dutch population revealed a 7.47 expected cases. The calculated SMR for breast cancer risk in patients treated hyperprolactinemia was 1.07 (95% confidence interval 0.50-2.03). In conclusion, there is no clear evidence for increased breast cancer risk in female patients treated for either idiopathic hyperprolactinemia or prolactinomas. The uncertainty about the exact risk that is due to the relatively low number of breast cancer cases, should be overcome by pooling results in a future meta-analysis.

Mortality in acromegaly: a metaanalysis.

CONTEXT: Several studies have assessed mortality risk in patients treated for acromegaly. All studies found a mortality that was higher than expected for the general population, but most of these increases were not statistically significant. For this reason, it is not formally established whether mortality in acromegaly is different from the general population. OBJECTIVE: The objective of the study was to address the all-cause mortality risk in patients with acromegaly. DESIGN: The study was a metaanalysis. METHODS: Sixteen studies on mortality in patients with acromegaly were included. The principal outcome of the metaanalysis was the weighted average of the standardized mortality ratio (SMR) of all studies. In addition, we performed a subgroup analysis of studies in which more than 80% of the patients were treated by transsphenoidal approach. RESULTS: The weighted mean of the SMR from all 16 studies was 1.72 (95% confidence interval 1.62-1.83). In studies with transsphenoidal surgery as the primary therapy, the weighted mean of the SMR was 1.32 (95% confidence interval 1.12-1.56). CONCLUSIONS: This metaanalysis shows increased all-cause mortality in acromegalic patients, compared with the general population, even after transsphenoidal surgery.

Microbiological challenge of four protective devices for the reconstitution of cytotoxic agents.

AIMS: To evaluate the susceptibility to microbial contamination that occurs during simulated handling of protective devices for the preparation of cytotoxic drug solutions. METHODS AND RESULTS: Four devices, i.e. Chemoprotect spike, Clave connector, PhaSeal and Securmix were challenged with low and high inocula of micro-organisms. The cells, transferred to the connected vials during repeated manipulations of the devices were counted by means of solid-phase cytometry. Of the four devices, PhaSeal afforded the lowest transfer of micro-organisms. Secondly, the efficiency of procedures for the disinfection of an artificially contaminated rubber stopper was compared prior to connection of the vial to the PhaSeal device. Spraying or swabbing alone was inadequate, as opposed to a combination of spraying [0.5% or 2.0% (w/v) chlorhexidine in isopropanol] and swabbing [70% (v/v) isopropanol]. CONCLUSIONS: Although Phaseal afforded the lowest transfer of micro-organisms, adequate disinfection of the vial prior to connection remains required. SIGNIFICANCE AND IMPACT OF THE STUDY: Unlike aspects of operator protection, which are well documented, the microbiological safety of protective devices for the preparation of cytotoxic drugs has not been addressed in the literature. This study estimates the susceptibility to microbial contamination during handling of four commonly used devices.

The James Lind Library: explaining and illustrating the evolution of fair tests of medical treatments.

The James Lind Library (www.jameslindlibrary.org) has been established to improve public and professional general knowledge about fair tests of treatments in healthcare and their history. Its foundation was laid ten years ago at the Royal College of Physicians of Edinburgh, and its administrative centre is in the College's Sibbald Library, one of the most important collections of historic medical manuscripts, papers and books in the world. The James Lind Library is a website that introduces visitors to the principles of fair tests of treatments, with a series of short, illustrated essays, which are currently available in English, Arabic, Chinese, French, Portuguese, Russian and Spanish. A 100-page book-- Testing Treatments--is now available free through the website, both in English and in Arabic and Spanish translations. To illustrate the evolution of ideas related to fair tests of treatments from 2000 BC to the present, the James Lind Library contains key passages and images from manuscripts, books and journal articles, many of them accompanied by commentaries, biographies, portraits and other relevant documents and images, including audio and video files. New material is being added to the website continuously, as relevant new records are identified and as methods for testing treatments evolve. A multinational, multilingual editorial team oversees the development of the website, which currently receives tens of thousands of visitors every month.

Cardiovascular risk factors after bariatric surgery: Do patients gain more than expected from their substantial weight loss?

BACKGROUND: While it has been established that even limited weight loss (5-10%) improves obesity-associated cardiovascular risk factors, it is not known if considerable weight loss following laparoscopic adjustable silicone gastric banding (LASGB) results in a cardiovascular risk profile that is comparable, worse, or even better than that of matched control subjects. METHODS: Cardiovascular risk factors were compared in three groups of 24 women each: an index group that had lost considerable weight following LASGB for morbid obesity (BMI>40 kg/m(2)), a control group with the same BMI that the index group achieved after weight loss, and a pre-weight loss group of women with a BMI above 40 kg/m(2). Anthropometric measures, fasting serum glucose, insulin, lipids, C-reactive protein, and homocysteine levels were determined and insulin sensitivity was estimated using a homeostasis model assessment index (HOMA-IR). RESULTS: After bariatric surgery, the index group had a BMI of 32.0+/-0.8 kg/m(2). This resulted in a significantly better cardiovascular risk profile than that of the pre-weight loss group (BMI 42.8+/-0.6 kg/m(2)). Unexpectedly, after weight loss, the index group had significantly lower systolic blood pressure, fasting serum insulin, and HOMA-IR than the BMI-matched (32.8+/-0.9 kg/m(2)) control group. Although not significant, diastolic blood pressure, LDL-cholesterol, and CRP levels were also lower. CONCLUSION: Considerable weight loss following bariatric surgery leads to a greater improvement in cardiovascular risk factors than might be expected from the weight loss.

[Generalizability of therapeutic trials]. / Generaliseerbaarheid van therapeutisch onderzoek.

The external validity of a therapeutic trial addresses whether the study results may be applicable to other patients beyond the original study population. The inclusion criteria of the original study are a good indicator of the extent to which new patients are comparable with the study population, based on key characteristics. If the patients included in the study are not representative of the target population, the external validity is limited. The external validity can also be limited by study aspects that are not related to the inclusion criteria, such as the treatment protocol, the treatment centre, or the country in which the original study was performed. In exceptional cases the external validity can involve patients that would have been excluded in the original study.

[The N-of-1 trial: the ideal study design that is underused]. / De N = 1-trial, de meest ideale onderzoeksopzet, die te weinig wordt gebruikt.

The randomised experiment in a single patient, the N-of-1 trial, is the best study design for demonstrating causality, for example between agent and effect. Despite this, this type of study is only encountered sporadically in medical journals. One reason for this is that even this type of design cannot definitively demonstrate causality, because different points in time are compared with one another. Moreover, the design is rather inefficient, since the results correspond with those from observation without randomisation, placebo control or blinding. Even so, the N-of-1 trial is the ultimate form of verification in, for example, the individualisation of treatment. For this reason, this form of study might be used more often.

Venous thromboembolism and risk of cancer in patients with rheumatoid arthritis.

Essentials Can venous thromboembolism (VTE) in rheumatoid arthritis (RA) patients be marker of cancer? RA patients with VTE and comparison cohorts from population-based registries were compared. Increased risk of cancer in RA patients with VTE during the first year of VTE was observed. Risk of cancer in RA patients was increased also during the longer period following VTE. SUMMARY: Background It is unknown whether venous thromboembolism (VTE) in rheumatoid arthritis (RA) patients can be a marker of occult cancer. Objectives To examine risk of cancer subsequent to VTE among RA patients compared with risk of cancer in an RA cohort without VTE and in a general population without RA and without VTE. Patients/Methods All RA patients with a first-time diagnosis of VTE (index date) during 1978-2013 and comparison cohorts were identified from population-based registries in Denmark. Results We identified three cohorts: 2497 RA patients with VTE, 11 672 RA patients without VTE and 12 730 persons from the general population. The cumulative incidence of cancer within the first year of the index date was 3.2% among RA with VTE, 2.2% among RA without VTE, and 2.0% in the general population cohort. Incidence rate ratios (IRRs) were 1.79 (95% confidence interval [CI], 1.37-2.33) for RA patients with VTE vs. RA patients without VTE and 2.12 (95% CI, 1.63-2.76) for RA patients with VTE vs. the general population. The IRR of cancer at > 1 to 36 years from the index date among RA patients with VTE was 1.16 (95% CI, 1.00-1.34) compared with the RA patients without VTE and 1.33 (95% CI, 1.15-1.53) compared with the general population. Conclusions We found an increased risk of cancer in RA patients with VTE during the first year following VTE and also during the longer follow-up period. Thus, VTE may not only be a result of inflammation and immunological dysfunctions associated with RA, but may also be a marker for occult cancer.

Risk factors for extended-spectrum ß-lactamase-producing Escherichia coli urinary tract infection in the community in Denmark: a case-control study.

OBJECTIVE: To verify the role of proton pump inhibitors (PPI) and nitrofurantoin, which have appeared as novel risk factors for carriage of extended-spectrum ß-lactamase (ESBL) -producing Escherichia coli, as risk factors for ESBL E. coli urinary tract infection (UTI). We included known risk factors to ascertain whether our findings are comparable with those of previous studies. METHODS: Population-based case-control study including 339 cases with community-onset ESBL E. coli UTI in 2007-2012, 3390 non-ESBL E. coli UTI controls and 3390 population controls. We investigated potential risk factors by estimating ORs and 95% CIs adjusting for sex, age and co-morbidity. RESULTS: Comparing cases with non-ESBL E. coli UTI, PPI use yielded an OR of 1.6 (95% CI 1.2-2.0) and antibiotic exposure gave an OR of 1.4 (95% CI 1.1-1.8); these were driven by nitrofurantoin (OR 1.8; 95% CI 1.3-2.6) and macrolides (OR 1.7; 95% CI 1.2-2.3). Other risk factors included previous hospitalization with one or two and more than two hospitalizations versus none yielding ORs of 1.9 (95% CI 1.4-2.5) and 4.6 (95% CI 3.2-6.8), recent surgery (OR 2.0; 95% CI 1.5-2.8), renal disease (OR 2.2; 95% CI 1.4-3.4), chronic pulmonary disease (OR 1.4; 95% CI 1.0-2.0) and cancer (OR 1.5; 95% CI 1.1-2.1). Comparing cases with population controls, we found that most risk factors were also risk factors for non-ESBL UTI. CONCLUSIONS: ESBL E. coli UTI were associated with previous hospitalization and surgery. Nitrofurantoin and macrolides augmented the risk. PPIs had a moderate effect but may be important facilitators of ESBL carriage due to their widespread use.

[No prior informed consent required for 'no-risk' scientific research]. / Geen voorafgaande 'informed consent' vereist bij wetenschappelijk onderzoek zonder risico of belasting.

Recent research has shown that prior informed consent not only leads to a lower response but also distorts the results of the study. The concern about the protection of the individual may not be given preference over the importance of participation in a study, in particular for those studies that carry a very limited or non-existent risk or that are not burdensome to the patient.

[Levels of evidence are insufficient]. / Niveaus van bewijskracht schieten tekort.

Medical knowledge is based on various types of research, each with its own 'indication' and 'contraindication'. Although the randomised controlled trial is highly useful to quantify small differences in treatment effects, it is not able to establish all medical knowledge needed at the bedside. In most instances of non-therapeutic research, observational data are more useful. Evaluating all medical knowledge on the basis of a single hierarchy of level of evidence is therefore seriously flawed.

[The N-of-1 trial: the ideal study design that is underused]. / De N = 1-trial, de meest ideale onderzoeksopzet, die te weinig wordt gebruikt.

The randomised experiment in a single patient, the N-of-1 trial, is the best study design for demonstrating causality, for example between agent and effect. Despite this, this type of study is only encountered sporadically in medical journals. One reason for this is that even this type of design cannot definitively demonstrate causality, because different points in time are compared with one another. Moreover, the design is rather inefficient, since the results correspond with those from observation without randomisation, placebo control or blinding. Even so, the N-of-1 trial is the ultimate form of verification in, for example, the individualisation of treatment. For this reason, this form of study might be used more often.

[Physicians and scientific research: slight decline of the numbers of physicians with a doctoral degree]. / Artsen en wetenschappelijk onderzoek: lichte teruggang van het aantal gepromoveerde artsen.

OBJECTIVE: To establish whether the number of physicians interested in a career in academia (i.e. research) is declining. DESIGN: Descriptive. METHOD: The researchers analysed the pre- and post-doctoral careers of PhD students at 3 university medical centres (VU Amsterdam, Nijmegen and Maastricht) in 4 separate reference years (1989, 1994, 1999 and 2003), using information from doctoral dissertations and the Dutch medical address book. The researchers recorded the gender of the students and the timing of the doctorate in relation to specialist training, university education and employment, as applicable. RESULTS: The total number of dissertations produced at the 3 medical faculties in the 4 reference years increased gradually by nearly a factor of 2 (1989: 112; 1994: 152; 1999: 198; 2003: 213). In terms of absolute numbers, the number of dissertations authored by physicians increased from 1989 to 1994 and again in 1999 (64, 90 and 105), but decreased slightly in 2003 (96). The percentage of female physicians obtaining a doctorate doubled during this period (1989: 9/64 (14); 2003: 28/96 (29)). Increasingly, physicians prepared their dissertation before or during their training as specialists or general practitioners (1989: 15/64 (23%); 2003: 51/96 (53%)). Ofthe clinical specialists who had received their doctorate, approximately half continued to work in an academic setting after obtaining their degree. This percentage remained approximately the same in all reference years (1989: 13/26 (50); 1994:19/35 (54); 1999: 21/45 (47); 2003: 21/40 (53)). CONCLUSION: Although the number of physicians performing scientific research as part of their doctoral degree project declined slightly in 2003 following an initial rise, our data indicate no cause for major concern. One reason may be increased interest in Clinical Research Fellow programmes. However, the future of medical research would look brighter if young physicians with doctorates had better career prospects within academic centres. To follow the academic careers of clinicians in The Netherlands, a national registry is needed to collect the type of data analysed in this study continually.

Meta-analysis of the risk of gastric stump cancer: detection of high risk patient subsets for stomach cancer after remote partial gastrectomy for benign conditions.

Controversy about gastric cancer risk after partial gastrectomy exists, especially in the United States. Therefore, we performed a meta-analysis to determine overall relative risk and weighted mean relative risk for subsets of postgastrectomy patients, define possible high risk patients suitable for surveillance, and assess for publication bias which would overestimate risk. If 2 studies were excluded because of heterogeneity, overall relative risk (RR) for gastric stump cancer in 22 studies analyzed was 1.66 [95% confidence limits (CL), 1.54-1.79]. With these 2 studies included, the RR summarized with a random effects model to account for study heterogeneity was 1.46 (95% CL, 1.18-1.82). No obvious evidence of publication bias was detected. Patients 15 years or more postoperative had a weighted mean RR of 1.48 (95% CL, 1.31-1.67) and patients 5-14 years postoperative had a RR of 0.91 (95% CL, 0.71-1.17) (P = 0.026). Patients operated upon for gastric ulcer had a weighted mean RR of 2.12 (95% CL, 1.73-2.59) and patients with duodenal ulcers had a RR of 0.84 (95% CL, 0.66-1.05) (P = 0.001). The weighted mean RR for females was 1.79 (95% CL, 1.39-2.29) and for males 1.43 (95% CL, 1.27-1.62) (P = 0.074). For Billroth II gastrectomy the weighted mean RR was 1.60 (95% CL, 1.15-2.18) and for Billroth I gastrectomy 1.20 (95% CL, 1.01-1.42) (P = 0.220). Although differences in risk between subsets of postagastrectomy patients seen to exist, recommendations concerning endoscopic surveillance await further studies of cost-benefit analysis.

[Snippets of past medical research: worth saving?]. / Snippers uit een medisch onderzoeksverleden.

Medical researchers and physicians are not trained in the care of their written or digital past. Here, a scientific historian and a clinical epidemiologist reflect on possibilities for archiving the records of medical research in order to safeguard scientific legacies. In addition to the use of so-called witness seminars, which may suffer from interpretation by 'hindsight', archival material is necessary to understand and interpret the past. A particular problem is how to establish archives of day-to-day scientific undertakings that rely almost entirely on digital media for measurements, communication and publication. The recently developed conviction that good scientific practice encompasses an obligation to store all relevant information about medical research projects at the time of publication - for future replication or verification - might dovetail with the goals of medical historians, and thus might become a rich source of historical data in the future.

Female hormones and thrombosis.

Exogenous hormones are used by more than a hundred million women worldwide as oral contraceptives or for postmenopausal hormone replacement. Oral contraceptives increase the risk of venous thrombosis, of myocardial infarction, and of stroke. The risk is highest during the first year of use. The venous thrombotic risk of oral contraceptives is high among women with coagulation abnormalities and with so-called third-generation contraceptives (containing desogestrel or gestodene). The risk of myocardial infarction does not appear to depend on coagulation abnormalities or the type of oral contraceptive. Hormone replacement therapy increases the risk of venous thrombosis. This risk is also highest in the first year of use and among women with coagulation abnormalities. The risk becomes very high in women with a previous venous thrombosis. Randomized trials have not confirmed a beneficial effect of postmenopausal hormones on the occurrence of myocardial infarction.

Bleeding complications in oral anticoagulant therapy. An analysis of risk factors.

BACKGROUND: Insufficient data are available about the safety of oral anticoagulant therapy. The specialized organization of thrombosis services in the Netherlands can provide important information on the bleeding risk and various risk factors for bleeding in patients receiving oral anticoagulant therapy. METHODS: In a follow-up study over a 12-month period beginning in January 1988 on all patients treated by the Leiden Thrombosis Service, the frequency of bleeding complications was assessed. A Poisson regression model was used to assess the relative contribution to the bleeding risk of age, sex, target zone (intensity of anticoagulant effect aimed at), achieved intensity of anticoagulant therapy (International Normalized Ratio), and the type of coumarin derivative used. RESULTS: Six thousand eight hundred fourteen patients experienced 1003 bleeding complications (16.5 per 100 treatment-years), 162 of which were major bleeds (2.7 per 100 treatment-years). Bleeding increased significantly with age (32% increase for all bleeding, 46% for major bleeding for every 10-year increase in age in comparison with age < 40 years). Women had more minor bleeding complications than men, whereas both sexes experienced major bleeding in an equal frequency. There was no influence of target zone, while every one-point increase in International Normalized Ratio gave 42% more major bleeding (54% more regarding all bleeding). Use of acenocoumarol resulted in fewer bleeds (26% less regarding all bleeding and 46% less regarding major bleeding) than use of phenprocoumon. CONCLUSIONS: The risk of anticoagulant therapy in a routine, real-life situation is similar as in the setting of several well-organized clinical trials. The risk of bleeding complications rises significantly with age and with the achieved intensity of anticoagulation, and is dependent on the type of coumarin derivative that is used.