PubH 6003: Principles and Practice of Epidemiology Week 6 Case Study “Tampon and Toxic Shock Syndrome”

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George Washington University PUBH 6003 PubH 6003: Principles and Practice of Epidemiology Week 6 Case Study “Tampon and Toxic Shock Syndrome” Objectives2 After completing this case study, th ... e participant should be able to: 1. Describe the concepts, applications, and limitations of matching in case-control studies. 2. Interpret the data from case-control studies. 3. Discuss the issues involved in appropriate selection of controls in case-control studies. THERE ARE A TOTAL OF 66 POINTS FOR THIS CASE STUDY In 1979, three cases of an unusual illness were reported to the Wisconsin State Health Department. The three cases, all of which involved women, were characterized by fever, hypotension, diffuse rash, desquamation, and impairment of multiple organ systems. This clinical presentation was reminiscent of an illness described a year earlier by Todd et al. and given the name toxic shock syndrome (TSS). Todd's case series comprised four females and three males aged 8-17 years, five of whom had focal Staphylococcus aureus infections. As a result of the case reports, Wisconsin and Minnesota established TSS surveillance systems within their states. By January of 1980, the two states had identified a total of 12 cases, all of which occurred in women. Eleven of the 12 had been menstruating at the onset of illness, and, anecdotally, “most” had been using tampons during the corresponding menstrual period. Soon, CDC was notified. In February, Utah established an active surveillance system. During the spring of 1980, reports of TSS continued to trickle in to CDC, mostly from Wisconsin, Minnesota, and Utah. The lead article of the May 23, 1980 issue of the Morbidity and Mortality Weekly Report (MMWR) gave an account of the first 55 reported cases of TSS. Of 40 patients from whom a menstrual history was obtained, 38 (95%) had onset of illness within 5 days following onset of menses. The reported case-fatality ratio was 7/55, or 13%. In Wisconsin, where surveillance had been very active, the case-fatality ratio was 3.2 %. Extensive publicity followed this report, and CDC began to receive reports of TSS from other states. In mid-June, CDC conducted its first TSS case control study (CDC-1). Published in the MMWR of June 27, the study of 52 female cases and 52 age- and sex-matched friend controls found a statistically significant association between tampon use and TSS (p=0.02). The report cited two independent preliminary studies from Wisconsin (31 cases) and Utah (12 cases). The Wisconsin study also found a statistically significant association between tampons and TSS (p=0.02), but the Utah study did not (p=0.22). Neither the CDC-1 study nor the Wisconsin study found a statistically significant association between any specific brand of tampon and TSS.3 QUESTION 1 (3 points): Would you conclude that TSS is associated with tampon use? Explain the basis for your answer. It seems like there is an association as 11 of the 12 had been menstruating at the onset of illness, and, anecdotally, “most” had been using tampons during the corresponding menstrual period in Wisconsin and Minnesota. But as sample size is small chances of errors are higher and a definitive causality cannot be determined. Also, Case control study the evidence is not absolute. The analyses (unmatched) from the three studies, limited to menstruating women, are summarized below. Tampon users are women who used tampons at any time during their last menstrual period. [Show More]

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