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Published on: May 24, 2020

Thromboembolism and oral contraceptives. (Letter to the editor)

A F Johnson

    JAMA
    |October 2, 1972
    PubMed

    Insights

    The quality of scientific studies on oral contraceptives and thromboembolism significantly impacts reported incidence rates. Higher quality research shows a greater risk, challenging current low-incidence findings.

    Area of Science:

    • Medical research methodology
    • Pharmacovigilance
    • Epidemiology

    Background:

    • The relationship between oral contraceptives and thromboembolic episodes has been debated, with studies examining retrospective and prospective data.
    • Previous analyses, such as those by Drill and Calhoun, have cited various articles to support their conclusions on the incidence of these events.

    Purpose of the Study:

    • To critically evaluate the scientific merit of studies cited in the discussion of oral contraceptives and thromboembolism.
    • To assess whether the quality of scientific evidence influences the reported incidence of thromboembolic episodes.

    Main Methods:

    • Review and re-evaluation of scientific articles previously cited in discussions on oral contraceptives and thromboembolism.
    • Ranking of selected articles based on scientific merit concerning the embolism problem.
    • Analysis of the correlation between study quality, reported thromboembolism incidence, and sample size.

    Main Results:

    • Many cited articles lacked the rigor of research reports, with some offering only general, non-quantitative comments.
    • When ranked by scientific quality, studies with higher merit reported a greater incidence of thromboembolism.
    • Higher quality studies also tended to involve fewer subjects.

    Conclusions:

    • The overall reported incidence of thromboembolic episodes may be underestimated due to the inclusion of less rigorous studies with large sample sizes.
    • There is a potential bias in current assessments of oral contraceptive risks, necessitating a re-evaluation based on higher-quality scientific evidence.

    Keywords:
    BiologyBlood Coagulation EffectsContraceptionContraceptive Methods--side effectsDiseasesEmbolismFamily PlanningHematological EffectsHemic SystemOral Contraceptives--side effectsPhysiologyThromboembolismVascular Diseases

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