ISSN:1362-5187    

DOI:10.3109/13625189609150649

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The discovery of plasma resistance towards activated protein C, APC resistance, and its main genetic background, the presence of a single-point mutation in the gene coding for coagulationfactor V, factor V Leiden, has, together with renewed documentation of a link between oral contraceptive use and thrombosis, increased the understanding of the pathophysiology, but also the demands to the prescribers, of the pill. Only with knowledge about hemostasis, thrombophilia, DNA technology, its use and limitations, epidemiology, and absolute risk,can general prac tition ers perform good clinical practice. This short survey tries to cover some of these aspects and to suggest directions for future research.

ISSN:1362-5187    

DOI:10.3109/13625187.11661689.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

New epidemiological studies have demonstrated a higher risk of venous thromboembolism among users of oral contraceptives (O Cs) with third-generation progestogensdesogestrelorgestodenecompared with users of OCs with second-generation progestogenslevonorgestrelornorgestrel.As th e absolute risk of venous thromboembolism among users of O Cs in general is lower in the new studies than in previously published studies, and as several important potential confounders are not controlled for in the new studies, the real difference in risk of venousthromboembolism between users of third- compared with second-generation products may be smaller than indicated in these new studies. At the same time, the risk of myocardialinfarction may be smaller among users of third- compared with users of second-generation products.Until further epidemiological data emerge, it is therefore difficult to make general recommendations other than to use O Cs with a low estrogen dose, and to make individual recommendations based on age, individual wish, and individual risk factors.

ISSN:1362-5187    

DOI:10.3109/13625187.11661690.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Recent epidemiological studies have reported an approximately two-fold, significant, increased odds ratio for venous thromboembolism in users of third-generation oral contraceptives(OCs) compared to users of second-generation O Cs. However, in each study, this association is of borderline . statistical significance, and the studies do not indicate an increase in theabsolute risk of venous thromboembolism for users of third-generation O Cs compared with the data from prior studies primarily involving second-generation products. The data derivedfrom these recent studies show a lower reported incidence of venous thromboembolism with the use of second-generation O Cs over time compared to the prior studies, while the incidence of venous thromboembolism for users of third-generation OCs is approximately equal to that previously reported for second-generation products. Generally, evidence has shown that therisk of venous thromboembolism and the impact on hemostatic parameters are reduced with declining estrogen dose. In addition, there is no evidence of a clinically significant effect ofthe OC progestogen doses on hemostatic parameters.These inconsistencies point to factors other than a causal relationship to explain the higher risk of venous thromboembolism in users of third-generation OCs. An examination of factorsnot included in the recent studies has identified at least three potential biases that should be considered: prescription bias, a 'healthy-user' effect and referral bias.Available data on prescription bias come from marketing research surveys, databases of prescribing patterns, epidemiological databases and the recent studies. These data indicatethat the recently introduced third-generation OCs have been more extensively used by younger women , for shorter periods of time, and by women with risk factors for venous thromboembolism than have the second-generation OCs. There is also evidence for a healthy usereffect, whereby women who were most susceptible for venous thromboembolism have left the cohort of users of second-generation OCs as a result of a venous thromboembolism during pregnancy or early OC use, and thus were possibly not included in these recent studies. The women remaining in the cohort, who are included in the recent studies, are lesssusceptible to venous thromboembolic events than are those making up the cohort of women using third-generation OCs. In addition, there are indications that referral bias has occurred because women with risk factors for venous thromboembolism (who disproportionately receive third-generation OCs) are more likely to be referred to a hospital for investigation ofpossible symptoms of venous thromboembolism, and thus users of third-generation OCs have the potential to be over-represented among cases.These biases act spuriously to increase the observed odds ratio for the first-time occurrence of venous thromboembolism amongst users of third-generation OCs, when compared tousers of second-generation OCs. None of the recent epidemiological studies have been able to adjust for the three major biases. These biases are Likely to contribute to, or even totally account for, the small increased risk of venous thromboembolism observed for users of third-generationOCs when compared to that for users of second-generation OCs.

ISSN:1362-5187    

DOI:10.3109/13625187.11661691.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Objective: To investigate whether patients changing from their current oral contraceptive (OC) are preferentially switched to third-generation preparations.Method: The database comprised 12 months of medical records generated during 1990-91 from 693705 patients and 153687 OC users aged 14-45 years registered with 398 practices in the United Kingdom. Subjects who switched OC preparations were identified.Results: A total of 16197 women (10.5%) switched OC preparations at least once during the study period. There was a statistically significant net switching from second-generation OCs to third generation OCs with a ratio of 1.19 (95% C l, 1.12-1.26). This switching behavior took place in both younger(25 years.Conclusion: Bias resulting from preferential switching of women from second-generation to third-generation OCs may have influenced the results of recently published studies on combined OCs and the risk of venous thromboembolism. Studies of venous thromboembolismin women using OCs should either restrict from the study women who have switched preparations or should include switching as a variable in any analysis.

ISSN:1362-5187    

DOI:10.3109/13625187.11661692.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

A survey among oral contraceptive (OC) prescribers in the United Kingdom, Germany, Sweden and the Netherlands was performed to investigate OC prescription patterns before and after recent publicity in the media about studies reporting a higher risk of venous thromboembolism with OCs containing third-generation progestogens as compared to OCs containing second-generation progestogens. Before this publicity, most physicians prescribed third-generation OCs as their first-choice formulations for normal healthy women as well as for young girls (<20 years) and older fertile women (30-35 years). In women presenting with cardiovascular risk factors, third-generation progestogens (desogestrel,gestodene) were considered safer and were five times more often prescribed than second-generation preparations (71 % versus 14%). Most prescribers considered ethinylestradiol to be the most important component in relation to the risk of venous thromboembolism(71 %), myocardial infarction (66%) and stroke (67%). In addition, for women presenting with cardiovascular risk factors, OC preparations containing 20 or 30 ug ethinylestradiol were considered safer than preparations containing 35 or 50 ug ethinylestradiol. Althoughthe vast majority of prescribers (78%) stated that their attitudes towards safety of third generation OCs had not changed since the recent publicity and the regulatory actions in some countries, 56% had changed their prescribing practice, largely due to patient concern about the safety of third-generation OCs. The results from this survey strongly suggestthat, prior to the recent publicity, most prescribers considered third-generation OCs to be safer than second-generation preparations. Because of this perceived better safety profile, physicians have selectively been prescribing third-generation OCs to women at increased risk of cardiovascular disease. This pattern of selective OC prescribing may have seriouslybiased the results of the recently published studies on OCs and venous thromboembolism in favor of second-generation OCs.

ISSN:1362-5187    

DOI:10.3109/13625187.11661693.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

A total of 2674 women were recruited to participate in a multicenter oral contraceptive(QC) study on hemostasis. At baseline, protein S activity less than 60% of normal values was found in two volunteers (0.75 per 1000) and the antithrombin III activity was less than 60% of normal values in three volunteers (1.1 per 1000). All measurements were confirmed by asecond assessment. In contrast, of the 28 women presenting with protein C levels less than 60% of normal values, only six were confirmed (2.3 per 1000). Qf these, one was also protein S-deficient. Seven women could not be studied twice and 15 were false- low according to their normal control values. These data suggest that routine screening of the hemostaticsystem may reveal findings suggestive of inhibitor deficiencies in as many as 3.75 per 1000 of apparently healthy candidates for QCs. However, our data also demonstrate that unselectedscreening is compromised by a considerable rate of false-positive results and cannot generally be recommended. However, screening of coagulation inhibitors is feasible in women with afamily history of thromboembolic disease.

ISSN:1362-5187    

DOI:10.3109/13625187.11661694.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Objectives:To review our studies on the clinical and metabolic impact of contraceptive methods in women with insulin dependent cliabete mellitus (IDDM) and women with previousgestation al diabetes meUitus (GDM) in order to provide suggetions for the contraceptive counselling of these women.Methods:The clinical events following first insertions of copper IUDs were studied in 103 women with !DOM and in 119 non- diabetic women. Moreover we studied the effects onglycometabolic control and lipid metabolism in women with well-controlled IDDM using low-dose oral contraceptives (OCs) containing ethinylestradiol combined with norethisterone(n = 10) , levonorgestrel (n = 9) or gestodene (n = 11 ). Hemostatic and endothelial function was also studied in the women using the gestodene-containing preparation. Finally, we studiedthe impact of oral contraceptives on the insulin sensitivity in women with previous GDM.Results:The continuation rates and indications for medical removal of the IUDs were similar in the diabetic and the non-diabetic women. There was no increased pregnancy rate or increasedfrequency of pelvic inflammatory disease in the diabetic women.The glycemic control was not changed by the OCs and none of the treatment regimens were associated with changes in plasma lipids linked to increased risk of atherosclerosis. Indicationsof increased fibrin formation, which seemed to be compensated by increased fibrinolytic activity, were noted with the gestodene-containing preparation . None of the women developedmicroalbuminuria during the study. Compared to normal women, we found reduced insulin sensitivity in the women with previous GDM using the pill.Conclusion:Intrauterine devices and barrier methods can be used by diabetic women with the same reservations as in the general population. Low-dose OCs do not influence the glycemiccontrol and have no adverse impact on plasma lipids. The balance between fibrin formation and resolution was maintained during intake of the gestodene-containing pill. Our findings suggestthat combined oral contraceptives can be used in women with uncomplicated IDDM and in women with previous GDM if clinical and metabolic monitoring can be ensured

ISSN:1362-5187    

DOI:10.3109/13625187.11661695.1996

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:1362-5187    

DOI:10.3109/13625189609150657

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:1362-5187    

DOI:10.3109/13625189609150658

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor