Walter O. Spitzer

First-time use of newer oral contraceptives and the risk of venous thromboembolism

Recent epidemiologic studies reported that the risk of venous thromboembolism (VTE) was higher with the use of the newer third generation oral contraceptives than with second generation agents. Although the overall findings of these studies are similar, the results, as they relate to patterns and duration of oral contraceptive use particularly among first-time users, are inconsistent. We reanalyzed data from the Transnational case-control study to assess the risk of VTE associated with first-time use of oral contraceptives as a function of its duration of use. Over the period 1993 to 1995, 471 cases of venous thromboembolism were identified in Germany and the United Kingdom. For each case, up to four controls were obtained, for a total of 1772 controls. Data on oral contraceptive use and confounding variables, including data on sociodemographic, lifestyle, medical history, and family history of disease, were obtained by interview. Data analysis was based on the 105 cases and 422 controls who were first-time users of second or third generation agents, or never users of oral contraception. Rate ratios, adjusted for confounders and approximated by odds ratios, were estimated as a continuous function of duration of oral contraceptive use by logistic regression and quadratic spline models. We found, for first-time users, that the adjusted rate ratio of VTE as a function of the duration of oral contraceptive use is essentially identical for second and third generation pills relative to never users. This rate ratio increases to around 10 in the first year of use and decreases to around two after 2 years of use, remaining at this risk level thereafter for both second and third generation agents. We conclude that second and third generation agents are associated with identical risks of venous thromboembolism when they are prescribed to women who are using oral contraceptives for the first time ever.

Quality-of-Care Appraisal in Primary Care: A Quantitative Method

A reproduceable method has been developed for measuring the quality of clinical care provided by physicians and nurse practitioners. The distinctive features of the method are the extended use of the tracer disease concepts, the evaluation of referrals, new procedures for probing the clinical operation of practices, a single blind design, emphasis on the use of the untouched medical record, the ability to compare results with measurements of concurrent outcome, and a relatively low cost. Three simultaneous approaches used in the method are described: surveillance of the management of indicator conditions, evaluation of clinical use drugs, and the assessment of referral decisions. The three approaches gave consistently similar results about the relative performances of the practices compared and were in agreement with concurrent outcome studies. The method was successfully implemented in a health care experiment.