A guide to interpreting contraceptive efficacy studies
Article Abstract:
When clinicians advise women regarding contraception, they need to understand the efficacy of various products. Interpretation of results from research on contraceptive devices, however, can be extremely difficult unless one understands the ways in which efficacy is measured. Efficacy information can be gathered from population surveys or from clinical studies. These investigations may be either prospective (following subjects over time) or retrospective (reviewing outcomes that were previously recorded). Contraceptive failure may be measured by the Pearl index (number of failures per 100 woman-years of using the method) or the life table analysis, which calculates a failure rate for each month the method is used. An ideal clinical design is not possible. Bias in studies of contraceptive failure can result from: different ways of using the contraceptive; the way a pregnancy is reported (by the woman or by laboratory test); the ways subjects who are 'lost' to follow-up are handled statistically; certain statistical and record-keeping problems; subject selection; and inherent conflicts of interest when research is performed by companies that manufacture contraceptive products. Statistics regarding the author's estimates of accidental pregnancy rates with different contraceptives are presented, indicating the lowest expected failure rate, and the typical rate. Clinicians are cautioned to pay careful attention to these variables when formulating their recommendations to patients. A summary of the main points that should be kept in mind in reading research studies on this topic is presented. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Obstetrics and Gynecology
Subject: Health
ISSN: 0029-7844
Year: 1990
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PAPNET-assisted rescreening of cervical smears: cost and accuracy compared with a 100% manual rescreening strategy
Article Abstract:
Computer-aided rescreening of cervical Pap smears using the PAPNET system may not identify many more cervical abnormalities and can be very expensive. Pap smears that are judged normal or benign on initial screening can be rescreened by another technologist or device to improve diagnostic accuracy. Researchers used PAPNET to screen 5,478 cervical samples that already had been screened twice by technologists. PAPNET identified 6 slides that contained atypical cervical cells. The high cost of automated rescreening was not justified by any significant improvement in cervical cancer testing.
Publication Name: JAMA, The Journal of the American Medical Association
Subject: Health
ISSN: 0098-7484
Year: 1998
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