CDC EIS Summer Course, 1999: Toxic Shock Syndrome -Student Guide Page |4 As mentioned above the CDC- 1 study was a matched-pair case- control study. When the matched pair fashion. Their analysis of CDC-1 study was published in a peer- continual tampon use during the index reviewed journal, the authors displayed and menstrual period is shown in Table 4. analyzed the data in Table 4: Continual Tampon Use During Index Menstrual Period, CDC Study (#1) of Toxic Shock Syndrome, 1980 CONTROLS 33 + 16 = 49 Exposed Unexposed CASES Exposed 1+ 2 = 3 e=33 f=16 OR =f/g Unexposed g=1 h=2 x 2 = (f-g ) 2 / (f+ g ) 34 19 Question 3: Comment on the difference between this 2- by -2 table (Table 4) and previous ones . This table shows matched pairs. It shows cages with a pair of exposed +unexposed. It also shows controls with exposed + unexposed. Question 4a: How many cases used tampons continually? 4q Question 4b: How many cases did not use tampons continually? Question 4c: How many controls used tampons continually? |3 Question 4d: How many controls did not use tampons continually? | 8CDC EIS Summer Course, 1999: Toxic Shock Syndrome -Student Guide Page 15 Question 5: Calculate the odds ratio and chi- square. fig : 16/ 1 = 16 Question 6: Calculate 95% test-based confidence limits using the following formula: Lower 95% limit = OR [1-(Z/chi) ] (chi = square root Upper 95% limit = OR [1+(Z/chi) ] of chi-square) For 95% CL's, Z =1.96 95 % CI: 0. 3476 to 48. 9 456 Question 7: Describe your results. oris of 274 cutsCDICE CDC EIS Summer Course, 1999: Toxic Shock Syndrome -Student Guide Page 16 Question 8: Have you been given enough information to decide whether the association is real? Question 9: Which 2- by -2 table format is appropriate for this study? National publicity followed the June 27 report CDC launched a second case-control study and continues almost daily throughout the (CDC-2) to test the hypothesis that one or summer of 1980. Though not documented by more brands of tampons might be more the studies cited, the lay press speculated strongly associated with TSS than were other that the then-new, highly absorbent tampons brands. The case group was to consist of the such as Rely brand might be responsible for 50 surviving females with onset of illness cases of TSS. By September 5, 1980, CDC had during July-August 1980. received reports of 272 cases. At that time, Question 10: What are some of the potential biases introduced by the MMWR reports and the intense publicity? . increased public awareness led to more reported cases, maybe overstating true incidence . The case group focused only on surviving females in a specific timeframe july-Aug which may not be representative . Due to awareness of TSS, maybe more false diagnoses of TSS simply based on symptoms ratherthan true comfortnation