Mortality and Causes of Death in Inherited Antithrombin Deficiency

To assess the contribution of inherited antithrombin deficiency to mortality, we investigated the causes of death in 14 families with inherited antithrombin deficiency. Between 1830 and 1994, 86 of 266 family members who had a probability of 0.5 or more for heterozygosity died. The causes of death were obtained for 58 of 66 deaths occurring between 1940 and 1994. Standardized mortality ratios (SMR) were calculated using mortality rates from the general population adjusted for age, sex and calendar period.

The overall SMR was 0.90 from 1830 to 1994 (95% C.1.0.72-1.11). From 1940 until 1994 44 men and 22 women died (SMR = 1.09, 95% C.I. 0.84-1.39; SMR men = 1.20, 95% C.I. 0.87-1.61; SMR women = 0.92,95% C.I. 0.58-1.39). No excess mortality compared to the general population was found for cancer (14 deaths) or circulatory diseases (28 deaths). A slightly increased mortality caused by respiratory diseases (7 deaths, SMR = 1.68,95% C.I. 0.68-3.47) seemed due to pneumonia (4 deaths, SMR = 2.86, 95% C.I. 0.78-7.32). Venous thromboembolic complications were listed once in association with a risk situation, and one other death could be attributed to fatal pulmonary embolism. Cerebral hemorrhages were listed three times. It could not be verified whether these hemorrhages were related to anticoagulant therapy; the frequency was slightly higher than the expected population figure (SMR = 1.49,95% C.I. 0.31-4.36). The mean age of death for all causes was 64 years; the two fatal thromboembolic episodes occurred at age 20 and 30 years.

The data show that antithrombin deficiency is associated with a normal survival and a low risk of fatal thromboembolic events. The use of long-term anticoagulant treatment in asymptomatic individuals should be considered carefully in view of the greater risk of fatal bleeding associated with long-term anticoagulant prophylaxis.

Assessment of a Bleeding Risk Index in Two Cohorts of Patients Treated with Oral Anticoagulants

In two cohorts of patients on oral anticoagulant therapy, routinely treated by the Leiden Thrombosis Service, the frequency of major bleeding complications was assessed during two years (1988 and 1991). With Poisson regression analysis the influence of the risk factors age, sex, target zone, achieved INR and type of coumarin derivative used were determined. Subsequently, a bleeding risk index was calculated, combining the results of the two cohorts. For various types of patients the relative risk of major bleeding complications was assessed.

Age and achieved INR were the most important and consistent risk factors: rate ratio (RR) for age in 1988 1.46 per 10 years increase (95% confidence interval [Cl] 1.20-1.78) and in 1991 1.57 per 10 years increase (95% Cl 1.23-2.00); RR per unit increase in achieved INR in 1988 1.42 (95% Cl 1.21-1.68) and in 1991 1.44 per unit increase in achieved INR (95% Cl 1.18-1.74). Two methods were used to combine the results of 1988 and 1991. In the first method the mean bleeding risk index was calculated: In (incidence) [natural logarithm of the incidence rate of major bleeding] = -5.64 +0.42 * age +0.26 % sex -0.29 * target range +0.36 % achieved INR -0.36 * coumarin type. In the second method only the consistent risk factors age and achieved INR were used: In (incidence) = -5.64 +0.42 % age +0.36 % achieved INR. These bleeding risk indexes can be used to assess the risk of major bleeding complications of individual patients and allow more individualized care by individual tailoring the desired anticoagulation.

Factor VII and Fibrinogen Levels as Risk Factors for Venous Thrombosis

The plasma levels of coagulation factor VII and fibrinogen are well known risk factors for arterial thrombosis. We tested the hypothesis that this association also exists for venous thrombosis. Additionally, MspI and Haelll polymorphisms in the factor VII and fibrinogen genes have recently been reported to be associated with the concentration of both proteins in the plasma. However, no conclusion could be drawn with respect to an increase or decrease in thrombosis risk. We undertook a population-based case-control study, in which 199 patients with a first, objectively confirmed episode of deep vein thrombosis, aged less than 70, and without a known malignant disorder were compared to 199 age-and sex-matched healthy controls, to evaluate the clinical importance of these reported findings.

For fibrinogen we found a positive level-related association between the plasma fibrinogen level and thrombotic risk. Subjects with a plasma fibrinogen greater than 5 g/1 had an almost 4-fold increase of thrombosis risk. The frequencies of the different Haelll genotypes were out of balance only for the thrombosis patients, with a deficit of the H1H2 genotype. Possession of an H1H2 genotype was associated with a 40% reduction in thrombosis risk.

For factor VII, neither the plasma level nor the MspI genotypes were related to deep vein thrombosis, although possession of a M2 allele was clearly associated with significantly lower factor VII levels. The frequencies of the Mspl-genotypes were the same for patients and control subjects and, exhibited Hardy-Weinberg equilibrium.

Our results support that plasma fibrinogen, a determinant of arterial thrombosis is also a risk factor for venous thrombosis, while factor VII plasma concentration is unrelated to deep vein thrombosis, which is supported by the data from the DNA analysis of polymorphisms.

Minor Events and the Risk of Deep Venous Thrombosis

Background Deep venous thrombosis is a common disease, with genetic and acquired risk factors. Many patients have a history of minor events (short periods of immobilisation such as prolonged travel, short illness, minor surgery or injuries) before onset of venous thrombosis. However, the role of these minor events has received little formal study. Also, we do not know how minor events might interact with the presence of genetic prothrombotic defects (factor V Leiden mutation, factor II mutation, protein C, S and antithrombin deficiency). Patients and Methods On the basis of case-control data from a thrombosis service in the Netherlands, we added a follow-up period for a casecross-over analysis of minor events as risk factors, and a case-only analysis for the interaction with factor V Leiden. A total of 187 patients with first, objectively diagnosed venous thrombosis of the legs, aged 15–70, without underlying malignancies and without major acquired risk factors entered the study. For the analysis of minor events in the case-cross-over analysis, we used a matched odds ratio; in the caseonly analysis, we used the multiplicative synergy index. Results In 32.6% of the 187 patients with deep venous thrombosis who did not have major acquired risk factors, minor events were the only external risk factors. Minor events increased the risk of thrombosis about 3-fold, as estimated in the case-cross-over analysis (odds ratio 2.9, 95% confidence interval 1.5–5.4). The synergy index between minor events and factor V Leiden mutation in the case-only analysis was 0.7 (95% confidence interval 0.3–1.5). Therefore, persons with factor V Leiden mutation who experience a minor event will have an estimated risk increase of about 17-fold, which exceeds the sum of the individual risk factors. Conclusions Minor events are likely to play an important role in the development of deep venous thrombosis, especially in the presence of genetic prothrombotic conditions.

Venous Thrombotic Risk in Family Members of Unselected Individuals with Factor V Leiden

The factor V Leiden mutation (FVL) leads to a seven-fold increased risk of venous thromboembolism (VTE). In thrombophilic families, 25% of carriers have experienced thrombosis before the age of 40 years. Aim of our study was to assess the association of FVL with VTE in first-degree family members of unselected symptomatic and asymptomatic carriers of FVL.

We tested 197 relatives of consecutive thrombosis patients with FVL and 36 relatives of asymptomatic carriers on the presence of FVL and the occurrence of VTE.

The incidence of VTE in relatives with FVL of symptomatic carriers was 0.34%/year. This was similar to the incidence in relatives with FVL of asymptomatic carriers. Kaplan Meier analysis in relatives of symptomatic propositi showed that at the age of 58 years, thrombosisfree survival was reduced to 75% in carriers and 93% in non-carriers (P < 0.05). Carriers of FVL had a three times higher thrombotic risk than non-carriers. In combination with environmental risk factors, FVL clearly adds to the risk of VTE. The thrombotic incidence rate in these unselected relatives with FVL, however, is considerably lower than was seen in carriers of thrombophilic families (1.7%/year). Therefore, special care should be paid to individuals with a positive family history of venous thrombosis while exposed to these risk factors.

Oral Contraceptives, Hormone Replacement Therapy and Thrombosis

Oral contraceptives and hormone replacement therapy are used by hundreds of millions of women worldwide. Since the early 1960s it is known that female hormones increase the risk of venous thrombosis, myocardial infarction and stroke. This risk is still present with current low-dose oral contraceptives and, even though in absolute terms the risk is small, oral contraceptives form the major cause of thrombotic disease in young women. The risk is higher during the first year of use (up to 1 per 1000 per year), with the use of desogestrel- or gestodene-containing oral contraceptives (“third generation progestogens”) and among women with a prothrombotic predispositon. Hormone replacement therapy increases the risk of venous thrombosis, while results of randomised trials so far do not substantiate the expectation of a beneficial effect on the risk of arterial cardiovascular disease. First results are emerging that specific subgroups of women, with prothrombotic or other abnormalities, may be at risk, especially during the first years of use of hormone substitution.

Venous Thrombosis, Oral Contraceptives and High Factor VIII Levels

Recently, it has been described that elevated plasma levels of factor VIII are a strong risk factor for venous thrombosis. We analysed the data of the Leiden Thrombophilia Study, a population based case-control study on the causes of venous thrombosis, to verify whether the risk due to oral contraceptive use was higher in women with higher factor VIII levels. Furthermore we investigated the joint risk of high factor VIII levels and oral contraceptive use.

We selected 155 premenopausal women with deep-vein thrombosis and 169 control subjects, aged 15-49, who were at the time of their thrombosis (or similar date in control) not pregnant, nor in the puerperium, did not have a recent miscarriage, and were not using injectable progestogens. Of the patients, 109 (70%) women had used oral contraceptives during the month preceding their deep-vein thrombosis, in contrast to 65 (38%) of the control subjects (index date), yielding an odds ratio for oral contraceptive use of 3.8 (95% CI 2.4-6.0). Of the women who suffered a deep-vein thrombosis 56 (36%) had high factor VIII levels (≥150 IU/dl) as compared with 29 (17%) of the control subjects, yielding an odds ratio for high factor VIII of 4.0 (95% CI 2.0-8.0), relative to factor VIII levels <100 IU/dl. The joint effect of oral contraceptive use and high factor VIII resulted in an odds ratio of 10.3 (95% CI 3.7-28.9), comparing women who had both with women who had neither. We conclude that there is an increase in risk due to oral contraceptive use in women with higher factor VIII levels and that both factors have additive effects.

A Genetic Propensity to High Factor VII Is not Associated with the Risk of Myocardial Infarction in Men

Several studies have examined the relation between factor VII and coronary artery disease by measuring factor VII levels in plasma and some found an association between high levels and disease. This suffers problems of interpretation concerning the causality of high factor VII levels, because factor VII levels may be affected by atherogenic risk factors and may become elevated as a consequence of atherosclerosis. We investigated the association between a genetic variant (353Arg→Gln), shown to be related to factor VII levels, and myocardial infarction in a large case-control study, including 560 cases and 644 controls. Individuals carrying the 353Arg-Arg genotype seemed to have a lower risk of myocardial infarction (odds ratio 0.80 [95% confidence interval 0.60-1.06]). In this study, we confirmed higher factor VII antigen and activity level in 529 men homozygous for the 353Arg allele compared with 115 men carriers of the 353Gln allele (around 20% higher).

Our results indicate that a genetic propensity to high factor VII levels is not associated with the risk of myocardial infarction. Since we confirmed the association of the 353Arg-Arg genotype with higher factor VII levels, we conclude that high levels of factor VII are not a causal determinant of myocardial infarction.

Risk factors for extended-spectrum β-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 β-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.

[Snippets of past medical research: worth saving?]

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.

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.

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.

Clinical outcomes after estimated versus calculated activity of radioiodine for the treatment of hyperthyroidism: systematic review and meta-analysis

BACKGROUND

Despite the long experience with radioiodine for hyperthyroidism, controversy remains regarding the optimal method to determine the activity that is required to achieve long-term euthyroidism.

OBJECTIVES

To compare the effect of estimated versus calculated activity of radioiodine in hyperthyroidism. Design Systematic review and meta-analysis.

METHODS

We searched the databases Medline, EMBASE, Web of Science, and Cochrane Library for randomized and nonrandomized studies, comparing the effect of activity estimation methods with dosimetry for hyperthyroidism. The main outcome measure was the frequency of treatment success, defined as persistent euthyroidism after radioiodine treatment at the end of follow-up in the dose estimated and calculated dosimetry group. Furthermore, we assessed the cure rates of hyperthyroidism.

RESULTS

Three randomized and five nonrandomized studies, comparing the effect of estimated versus calculated activity of radioiodine on clinical outcomes for the treatment of hyperthyroidism, were included. The weighted mean relative frequency of successful treatment outcome (euthyroidism) was 1.03 (95% confidence interval (CI) 0.91-1.16) for estimated versus calculated activity; the weighted mean relative frequency of cure of hyperthyroidism (eu- or hypothyroidism) was 1.03 (95% CI 0.96-1.10). Subgroup analysis showed a relative frequency of euthyroidism of 1.03 (95% CI 0.84-1.26) for Graves' disease and of 1.05 (95% CI 0.91-1.19) for toxic multinodular goiter.

CONCLUSION

The two main methods used to determine the activity in the treatment of hyperthyroidism with radioiodine, estimated and calculated, resulted in an equally successful treatment outcome. However, the heterogeneity of the included studies is a strong limitation that prevents a definitive conclusion from this meta-analysis.

The venous thrombotic risk of oral contraceptives, effects of oestrogen dose and progestogen type: results of the MEGA case-control study

OBJECTIVE

To assess the thrombotic risk associated with oral contraceptive use with a focus on dose of oestrogen and type of progestogen of oral contraceptives available in the Netherlands.

DESIGN

Population based case-control study.

SETTING

Six participating anticoagulation clinics in the Netherlands (Amersfoort, Amsterdam, The Hague, Leiden, Rotterdam, and Utrecht).

PARTICIPANTS

Premenopausal women <50 years old who were not pregnant, not within four weeks postpartum, and not using a hormone excreting intrauterine device or depot contraceptive. Analysis included 1524 patients and 1760 controls.

MAIN OUTCOME MEASURES

First objectively diagnosed episodes of deep venous thrombosis of the leg or pulmonary embolism. Odds ratios calculated by cross-tabulation with a 95% confidence interval according to Woolf's method; adjusted odds ratios estimated by unconditional logistic regression, standard errors derived from the model.

RESULTS

Currently available oral contraceptives increased the risk of venous thrombosis fivefold compared with non-use (odds ratio 5.0, 95% CI 4.2 to 5.8). The risk clearly differed by type of progestogen and dose of oestrogen. The use of oral contraceptives containing levonorgestrel was associated with an almost fourfold increased risk of venous thrombosis (odds ratio 3.6, 2.9 to 4.6) relative to non-users, whereas the risk of venous thrombosis compared with non-use was increased 5.6-fold for gestodene (5.6, 3.7 to 8.4), 7.3-fold for desogestrel (7.3, 5.3 to 10.0), 6.8-fold for cyproterone acetate (6.8, 4.7 to 10.0), and 6.3-fold for drospirenone (6.3, 2.9 to 13.7). The risk of venous thrombosis was positively associated with oestrogen dose. We confirmed a high risk of venous thrombosis during the first months of oral contraceptive use irrespective of the type of oral contraceptives.

CONCLUSIONS

Currently available oral contraceptives still have a major impact on thrombosis occurrence and many women do not use the safest brands with regard to risk of venous thrombosis.

Estimated age- and sex-specific incidence and prevalence of dopamine agonist-treated hyperprolactinemia

CONTEXT

Few data exist on sex- and age-specific incidence and prevalence of idiopathic hyperprolactinemia and prolactinomas.

OBJECTIVES

Our objective was to assess incidence and prevalence of dopamine agonist-treated hyperprolactinemia by age and sex.

DESIGN

From the PHARMO network, we identified an open cohort of patients who were ever dispensed dopamine agonists for hyperprolactinemia. The network includes complete medication histories for more than 2 million community-dwelling residents. Prolonged use of low-dose dopamine agonist is a reliable marker for hyperprolactinemia, provided that use for Parkinson's disease and lactation withdrawal is excluded. Diagnoses were verified by prolactin values in a random subsample using the same network.

RESULTS

We identified 11,314 subjects with at least one dispensing of dopamine agonist in the period 1996-2006, of whom 1607 subjects were considered to have dopamine agonist-treated hyperprolactinemia based on the prescribing pattern. The majority of patients were women (n = 1342, 84%). The diagnosis proved to be incorrect in only 1.5% of a random subsample. The estimated incidence rate of dopamine agonist-treated hyperprolactinemia for women was 8.7/100,000 person-years and for men 1.4/100,000 person-years. The highest incidence rate was found in women 25-34 yr of age: 23.9/100,000 person-years. The mean prevalence of ever treated female patients was almost five times higher (93.9/100,000) compared with male patients (19.6/100,000).

CONCLUSION

The incidence rates and the prevalence of dopamine agonist-treated hyperprolactinemia showed an overall preponderance in women, with a strong peak for women aged 25-34 yr. In men, no peak was found.

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.

[Generalizability of therapeutic trials]

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]

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.

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.

[The N-of-1 trial: the ideal study design that is underused]

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.

[Levels of evidence are insufficient]

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.

[Physicians and scientific research: slight decline of the numbers of physicians with a doctoral degree]

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.

[No prior informed consent required for 'no-risk' scientific research]

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.

[The investigation of gene-environment interaction using case-control comparisons]

Many chronic diseases are caused by the interaction of genes and environmental factors. Genetic epidemiologic research seeks to elucidate the role of genetic factors and their interaction with environmental factors in the occurrence of disease. Gene-environment interaction can be assessed using different types of case-control comparisons. The classic case-control design is suitable to investigate the association between multiple genes and environmental factors. Results can be presented in a two-by-four table. In a case-parents design, the genotype of each case is compared with the genotype of a fictitious control formed by the non-transmitted alleles from each parent. In a case-only design, the relationship between a genotype and an environmental factor is examined in a population of affected cases only. Both the case-parents and the case-only designs assume independence between genotype and environmental factors in the control group.

[The predictive value of autoantibodies in disseminating lupus erythematosus and rheumatoid arthritis]

In some conditions e.g. osteoporosis, hypertension and hypercholesterolaemia, certain phenomena precede manifestation of the disease and preventive measures can be taken long before the disease presents itself. In the same way systemic lupus erythematosus (SLE) and rheumatoid arthritis can be explored. Recently, studies have been published on healthy blood donors, who later developed SLE or rheumatoid arthritis, and in whom specific autoantibodies could be demonstrated. In SLE the autoantibodies are not specific enough to develop preventive strategies, but in rheumatoid arthritis in particular there are specific antibodies against cyclic citrullinated peptides (anti-CCP-antibodies) which are very specific. A clinical trial has been initiated in which HLA-DR4-positive people with raised autoantibody concentrations are given 1-2 intramuscular injections of dexamethasone with the aim of halving the antibody concentration and in the long term lowering the incidence of rheumatoid arthritis.

[Epoetin-induced pure red-cell aplasia]

A 73-year-old man, a 73-year-old woman, and a 57-year-old man with anaemia due to renal insufficiency were treated with epoetin. After 6-12 months, the haemoglobin level decreased despite dosage increases, after which the patients became dependent on regular transfusions of concentrated erythrocytes. The older man died from peritonitis following diagnostic examination because of the anaemia. The woman died from septic shock, even though epoetin had been replaced by darbepoetin. The haemoglobin level in the younger man returned to normal after the presence of antibodies against epoetin had been demonstrated, he had stopped using the drug, and he had started on immunosuppressive therapy following kidney transplantation. Since 1998, the number of patients with epoetin resistance due to the development of antibodies against the drug (epoetin-induced pure red-cell aplasia) has increased. This complication should be considered in every patient treated with epoetin who experiences unexplained transfusion-dependent anaemia.

[Breast cancer and the use of the hormones around the menopause]

Following the publication of the 'Million women study', commotion has broken out in the media about the relationship between hormone use around the menopause and breast cancer. In this study, women were asked about possible risk factors for breast cancer, including hormone replacement therapy, prior to breast cancer screening. After an average follow-up period of 2.6 years, it was found that breast cancer more frequently occurred among women who had recently used an oestrogen-progestagen preparation (relative risk (RR): 2.00; 95%-CI: 1.88-2.12), an oestrogen preparation (RR: 1.30; 1.21-1.40) or tibolone (RR: 1.45; 1.25-1.68) than among women who had not used either of these. Methodologically, the study contains both strengths and weaknesses. However, the findings agree with those from an earlier randomised study. Current users of hormone use were more likely than never users to die from breast cancer (RR: 1.22; 1.00-1.48). For the prescription of hormone replacement therapy, the twice as high relative risk of breast cancer together with the other potentially life-threatening side effects of hormone replacement therapy need to be weighed up against the complaints which form the indication for the prescription. Therefore, the advice for hormone replacement therapy continues to be that it should, if necessary, be made available as a treatment option for a short period (3 months) and only in the case of serious and debilitating complaints. Long-term preventative use, as happens in practice, is not indicated due to the risk of relatively serious side effects.

Multiple primary malignancies in osteosarcoma patients. Incidence and predictive value of osteosarcoma subtype for cancer syndromes related with osteosarcoma

The overall incidence of osteosarcoma is low. However, the occurrence of osteosarcoma in a setting of multiple primary tumours is not infrequent, although population-based incidence numbers are unknown. The occurrence of osteosarcoma and other malignancies is frequently related to treatment, and can also be the result of genetic predisposition as in patients with retinoblastoma, Li-Fraumeni syndrome, Werner syndrome and Rothmund-Thomson syndrome. The aim of our study is to establish the incidence of osteosarcoma associated with other malignancies in a populationwide study and to find out if these osteosarcomas have a specific subtype, that could draw attention to a genetic predisposition to malignancy. A list of all patients registered in the Dutch National Pathology Register, named PALGA, with a diagnosis of osteosarcoma between 1975 and May 2000 was retrieved. All patients with another malignancy besides osteosarcoma were selected. All patients registered in the same period with a tonsillectomy served as a control for the occurrence of malignancy in a normal population. In a second step, only osteosarcoma patients with a history of retinoblastoma or a malignancy before the age of 46 years, since these are most probable to have a hereditary cancer syndrome, were retained for further analysis. The osteosarcomas were subtyped as common, chondroblastic, fibroblastic, teleangiectatic, anaplastic, osteoclast-rich or small cell. As a control for osteosarcoma subtypes the data of 570 patients entered in two studies from the European Osteosarcoma Intergroup (EORTC/MRC) were used. Of all 938 patients registered with the diagnosis of osteosarcoma, 66 had a history of multiple primary tumours. Four patients had a surface osteosarcoma, three an extraskeletal osteosarcoma and 59 had intramedullar high-grade osteosarcoma. Of this last group, one patient was known with Rothmund-Thomson syndrome, one had retinoblastoma and 30 had their malignancies before the age of 46. Of these 32 patients, 17 had osteosarcoma of the long bones. Especially women seem to be more susceptible for the development of multiple primaries. In nine patients, the histological subtype could be assessed by revision of available histological slides. All of these patients had an osteosarcoma subtype other than common as opposed to 29% in the control group of the European Osteosarcoma Intergroup. It is concluded that although the incidence of osteosarcoma is low, the occurrence of another malignancy in osteosarcoma patients is higher than in the normal population. Specifically, osteosarcoma patients have a relative risk of 2.4 (95% confidence interval 1.88-3.07) to develop another malignancy. A noncommon subtype of osteosarcoma should draw attention to a possible genetic predisposition of the patient involved.

Living with epilepsy: long-term prognosis and psychosocial outcomes

OBJECTIVE

To analyze the impact of seizures on everyday life and the long-term effects of epilepsy on health status and psychosocial outcomes.

METHODS

Follow-up study was conducted of a cohort of consecutive patients newly diagnosed with epilepsy between 1953 and 1967. In 1995 (mean follow-up 34 years), a random sample of 333 patients received a questionnaire asking clinical and demographic information and validated measures for psychosocial outcomes. Comparisons were made with the general Dutch population.

RESULTS

The response rate was 73% (116 men and 127 women); mean age was 49.9 years (SD 11.2 years). Mean age at epilepsy onset was 15 years (SD 11 years); mean duration was 24.4 years (SD 13.1 years). In total, 134 (55%; 72 men and 62 women) patients were seizure-free for the previous 5 years, and 81 patients still had seizures in the last year. One hundred twenty-seven patients were taking antiepileptic drugs, of which 51 were on monotherapy. Epilepsy patients have a positive health evaluation, comparable with the general Dutch population. Fewer epilepsy patients married or had children than the general Dutch population; more patients live at home with their parents or in foster homes or institutions (p < 0.001). Having epilepsy at school age has a significant negative effect on learning achievement (p < 0.01). Employment status is affected less, though more epilepsy patients are unfit to work than individuals from the general population (p < 0.05).

CONCLUSIONS

Epilepsy has a marked negative impact on education and achievement in later life. Despite worse psychosocial outcomes than the Dutch population, patients with epilepsy cope well with their epilepsy, regardless of their handicaps.

Renal disease in relatives of Indo-Asian Type 2 diabetic patients with end-stage diabetic nephropathy

AIMS/HYPOTHESIS

Indo-Asian immigrants in The Hague, The Netherlands, have a nearly 40-fold higher risk of end-stage diabetic nephropathy compared to the Caucasian population. To detect a genetic susceptibility for nephropathy within the Indo-Asian population, we assessed whether familial clustering of nephropathy occurs in families of Indo-Asian Type 2 diabetic patients.

METHODS

We compared nephropathy prevalence between two groups of first-degree relatives of Indo-Asian patients with Type 2 diabetes; the first group (case relatives) consisted of 169 relatives of patients with end-stage diabetic nephropathy; the second group (control relatives) consisted of 161 relatives of diabetic patients who had no nephropathy. The case and control relatives were examined for diabetes, blood pressure, renal function, microalbuminuria and urine dipstick measurements.

RESULTS

The mean age was 41 years and similar in the case and control relatives. Diabetes was distributed equally in both family groups. We did not find more nephropathy in first-degree relatives of Indo-Asian Type 2 diabetic patients with end-stage diabetic nephropathy in comparison with the control-relatives.

CONCLUSION/INTERPRETATION

We could not detect a genetic susceptibility for diabetic nephropathy within the Indo-Asian population. The lack of familial clustering of renal disease in Indo-Asian diabetic patients points to a general genetic or environmental susceptibility for diabetic nephropathy in this population.

[Adverse cardiovascular effects of postmenopausal hormone replacement therapy]

The views on the effects of postmenopausal hormone-replacement therapy (HRT) on cardiovascular disease have moved from one end of the spectrum to the other over the past decades. The presumed beneficial effects of HRT on arterial cardiovascular disease were based on observational findings and have led to the widespread use of these agents. However, recent large-scale randomised, placebo-controlled trials have demonstrated that HRT in women with a history of arterial diseases initially increases the risk of recurrent disease, while offering no benefit in the long term. Healthy postmenopausal women on HRT have an increased risk of arterial cardiovascular events compared with those taking placebo (relative risk 1.29; 95% CI: 1.02-1.63). Finally, the risk of venous thrombosis and pulmonary embolism is increased with the use of HRT. These results demonstrate that bias and confounding can play an important role in observational research and underscore the importance of randomised, placebo-controlled trials when studying the efficacy of drugs.

No increase in mortality and morbidity among carriers of the C282Y mutation of the hereditary haemochromatosis gene in the oldest old: the Leiden 85-plus study

BACKGROUND

The C282Y mutation in the gene for haemochromatosis (HFE) has been associated with various diseases at middle age. However, recent studies indicate that penetrance of the C282Y mutation is low. We explored the association between the C282Y mutation, iron metabolism, and morbidity and mortality in participants of the Leiden 85-plus.

STUDY DESIGN

A cross-sectional comparison and prospective follow-up was conducted in two unselected cohorts of 661 and 552 subjects. All subjects were aged 85 years and over. We determined the prevalence of C282Y homozygous and heterozygous subjects, and the association between the C282Y mutation and iron metabolism, all-cause and specific causes of death.

RESULTS

Prevalence of C282Y homozygosity in both cohorts was 0.2% (1/661 and 1/552, respectively) and of C282Y heterozygosity was 12.4% (82/661) and 11.4% (63/552), respectively. These estimates coincide exactly with reported estimates in younger age groups. Median ferritin level was 97 microg L-1 (IQR 39-162) for heterozygous carriers and 89 microg L-1 (IQR 41-157) for noncarriers (P = 0.66). The serum ferritin concentration for one C282Y homozygous subject, a woman aged 86 years at the time of enrollment in 1986, was 392 microg L-1. Cardiovascular morbidity was comparable between the C282Y heterozygous subjects and the noncarriers in both study cohorts. All-cause and cardiovascular mortality of carriers of the C282Y mutation was similar to that in noncarriers.

CONCLUSIONS

We found two C282Y homozygous subjects, illustrating that homozygosity can be compatible with survival in very old ages. C282Y heterozygosity was not associated with history of cardiovascular disease morbidity, all cause mortality, cardiovascular mortality, or biochemical phenotype of haemochromatosis at old age.

[The importance of case reports as compared to evidence-based medicine and molecular explanation]

Over the past few decades case reports have become a much maligned form of medical research. Does the case report still have a place in modern medical science, which is based on evidence-based medicine on the one hand and genomics on the other? The answer is an emphatic 'yes': clinical case descriptions form a necessary basis for detecting new ideas--new disease entities, new aetiological clues, side effects and new treatments. They are also necessary in medical education, and are a time-honoured cornerstone of quality assurance: the clinical pathological conference where difficult or rare cases are discussed for the benefit of all. Case reports form the basis of progress in clinical science, independent of basic subjects or epidemiological insights. They will continue to be necessary in a context of discovery. Moreover, they can also provide convincing clinical evidence. Finally, a well-written case report must clearly state what is already known and what the case report adds to this.

[Risk factors in adult periodontitis: polymorphism in the interleukin-1 gene family]

Interleukin (IL)-1 alpha, IL-1 beta and IL-1 receptor antagonist (ra) play a major role in regulation of the inflammatory response in periodontal tissues. The aim of this study was to investigate the distribution of genetic variation in the IL-1 gene family among periodontitis patients and controls, taking into account smoking and microbiology as additional variables. There were 53 non-smoking and 52 smoking patients with severe adult periodontitis and 53 periodontal healthy controls genotyped for genetic variation in the IL-1 gene family. The presence of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans was established by culture techniques. A higher frequency of genotype+ (IL-1A*2 + IL-1B*2 + IL-1RN*2) was found in non-smoking periodontitis patients in whom P. gingivalis and A. actinomycetemcomitans could not be detected (42.1% vs. 11.3% in controls; p = 0.0068; or 5.7, 95% ci: 1.6-19.8). This data provide evidence that polymorphisms in genes of the IL-1 family are associated with severe adult periodontitis and may be a risk factor for severe periodontitis.

[Financing medical research in the Netherlands: start taking care of the future now]

Less money is spent on medical research in the Netherlands than in other industrialised countries, even though Dutch science, and certainly Dutch medical science, scores qualitatively among the best in the world. Part of the explanation is that a relatively large part of scientific research in the Netherlands is financed directly by the government. As a result of several rounds of cutbacks in government spending, that were executed each time by cutting research that performed less well, the remaining research groups are at high qualitative level and highly competitive. In countries that surpass the Netherlands, there is an important second stream of government funding via Medical and Health Research Councils. In the same countries, the pharmaceutical industry also provides more money for medical research. The other side of the coin is that medical research in those countries seems more or less 'for sale'. Too heavy dependence on market oriented research leads to doubts regarding the independence of medical research. International observers judged that the direct financing of research by government in the Netherlands was an enormous bonus since it leads to flexibility to start new topics and at the same time stability of positions. However, a major concern for Dutch science is that there are too few possibilities to attract and hold promising young people. It is especially difficult to keep promising young women; though this is true for all industrialised countries, the Netherlands lags behind its major competitors as far as the position of women in the higher ranks of science is concerned. These problems will have to be solved by stimulation programmes for young researchers and flexibility of the higher echelons. The educational system must not be directed only at the production of more doctors for medical practice, but also at sufficient scientific training for these doctors so that they will be able to comprehend new developments. The ordinary daily practice of medical science is to verify the usefulness of new developments--which is just as important as breakthroughs at the top. This means that there should be new investments, not only for top ranking scientists in fashionable areas, but also to maintain sufficient numbers of medical scientists at all levels. It cannot be foreseen where the next new developments will arise, and even in a small country, active research should be ongoing in many areas to maintain contact with the international research community. New investments should primarily be in direct government financing and in augmentation of streams of money via Medical and Health Research Councils.

Increased end-stage diabetic nephropathy in Indo-Asian immigrants living in the Netherlands

AIMS/HYPOTHESIS

We aimed to investigate the risk of end-stage diabetic nephropathy due to Type II (non-insulin-dependent) diabetes mellitus in Indo-Asian immigrants from Surinam.

METHODS

A demographically based case-control study was carried out in Surinamese Indo-Asian immigrants and Dutch Caucasian subjects. All patients with end-stage diabetic nephropathy who had started dialysis between 1990 and 1998 were identified through a national registry of all patients entering a renal replacement program in the Netherlands. The general population of native Dutch and Surinamese Indo-Asians were considered the control subjects.

RESULTS

Among Indo-Asian immigrants, the age adjusted relative risk of end-stage diabetic nephropathy was 38 (95 % CI 16 to 91) compared with the native Dutch population. The duration of diabetes until the start of dialysis treatment was similar in both ethnic groups, about 17 years.

CONCLUSION/INTERPRETATION

The Indo-Asian subjects had a nearly 40-fold increase in the risk for end-stage diabetic nephropathy due to Type II diabetes, compared with the native Dutch population. This was higher than expected on the basis of the eightfold higher prevalence of diabetes in the Indo-Asian population. The similar duration of diabetes until the start of dialysis treatment in both ethnic groups supports the hypothesis of a higher incidence of diabetic nephropathy in the Indo-Asian diabetic population. Early and frequent screening for diabetes and microalbuminuria is recommended in Indo-Asian subjects.

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.