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LARGE

EARNING. BOUT. (SYPHILIS). EACTOR. LARGE. RID. VALUATION. Schaffzin JK, Koumans EH, Kahn RH, Markowitz LE. Evaluation of syphilis reactor grids: optimizing impact. Sexually Transmitted Diseases 2003;30(9):700-706. LARGE. Reactor grids Methods for reactor grid evaluation Results

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LARGE

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  1. EARNING BOUT (SYPHILIS) EACTOR LARGE RID VALUATION Schaffzin JK, Koumans EH, Kahn RH, Markowitz LE. Evaluation of syphilis reactor grids: optimizing impact. Sexually Transmitted Diseases 2003;30(9):700-706.

  2. LARGE • Reactor grids • Methods for reactor grid evaluation • Results • Conclusions

  3. AgeGroups OPEN CLOSED Syphilis reactor grids STS Lab Results R W 1 2 4 8 16 32 20 30 40 50 60 70

  4. AgeGroups Syphilis reactor grids STS Lab Results R W 1 2 4 8 16 32 20 30 40 CLOSED 50 60 70

  5. R W 1 2 4 8 16 32 20 30 AgeGroups 40 50 60 70 Syphilis reactor grids STS Lab Results R W 1 2 4 8 16 32 20 30 VARIABLE AREA 40 50 60 70

  6. Reactor grid evaluation Objectives • 1. Evaluate the effect different grids and different prevalences have on: • 2. Identify characteristics of cases not investigated by grid design • Missed cases • Investigations that yield no cases

  7. Methods for grid evaluation steps • Identify population groups of reactors with different prevalence of syphilis, all of whom were investigated with known outcome and none of whom were applied to any grids • Select five grids representing the range of currently used grids • Apply groups of reactors to these five grids

  8. Selection of different population groups • 5 jail surveillance projects (1999-2001) • 1 mobile screening site (1999-2001) • All people with reactive confirmed serologies had follow-up and staging

  9. Prevalence of syphilis by group Prevalence among reactors New cases of syphilis Groups Group A (Milwaukee) 11,007 screened 260 reactors 143 55% Group B (Nashville) 10,754 screened 846 reactors 234 28% Group C* (Baton Rouge) 3,375 screened 196 reactors 18% 36 Group D (SF + MA) 13,012 screened 347 reactors 1% 5

  10. OPEN CLOSED NA Reactor grids selected Grid 5 Grid 1

  11. Most inclusive Grid outcome OPEN Grid 1 Grid 2 Grid 3 CLOSED Grid 4 Most exclusive Grid 5 Grid outcome Reactors closed Groups Group A (Milwaukee) 55% Group B (Nashville) 28% Applied to Grids Group C (Baton Rouge) 18% Group D (SF + MA) 1%

  12. Percent of reactors closed Groups A-D

  13. Group A (Milwaukee) 55% Grid outcome Cases Group B (Nashville) 28% Non-Cases OPEN Grid 1 Grid 2 Group C (Baton Rouge) 18% Grid 3 CLOSED “Cases Missed” Grid 4 Group D (SF + MA) 1% Grid 5 Cases Non-Cases Grid outcome, cases missed Case classification Groups Most inclusive Most exclusive

  14. Percent of syphilis cases not investigated Groups A-D

  15. Conclusions 1 Cases missed • Percent of cases missed depends on grid design

  16. Grid outcomes, non-cases investigated Cases Non-cases Grid 1 “Non-cases investigated” Grid 2 Grid 3 “Cases missed” Grid 4 Grid 5 Cases Non-cases Groups Grid outcome Case classification Group A (Milwaukee) 55% Group B (Nashville) 28% Open Group C (Baton Rouge) 18% Closed Group D (SF & MA) 1%

  17. Percent of non cases investigated Groups A-D

  18. Conclusions 2 Investigations of non-cases • Proportion of investigations that are not cases depends on prevalence of syphilis among reactors • Investigations of non-cases are virtually independent of grid design • Use of a grid doesn’t increase concentration of syphilis among investigated reactors

  19. Age distribution of early cases missed Female Male Total Cases Total Cases Grid Grid 1 2 3 4 5 1 2 3 4 5 2 5 10-19 1 1 Age Group 42 43 20-29 7 14 83 56 30-39 12 5 25 16 54 40-49 7 16 20 6 8 2 5 50-59 2 2 2 2 1 1 1 1 0 1 60-69 1 145 164 Total 0 2 9 19 42 0 1 1 12 49 • Cases excluded by age tend to be: • - Men ages 30-50 • - Women ages 20-40

  20. 6 3 WR 2 3 6 6 Titer 7 3 Trep only 1 1 3 2 7 15 18 1:1-1:2 1 4 10 18 3 15 19 14 1:4 1 4 5 14 1 1 1 19 17 9 1:8 1 1 81 117 1:16 1 3 1 145 164 Total 0 2 9 19 42 0 1 1 12 49 Titer distribution of early cases missed Female Male Total Cases Total Cases Grid Grid 1 2 3 4 5 1 2 3 4 5 • Cases excluded tend to have: • - RPR titer 1:1 – 1:4

  21. Overall conclusions The percentage of cases missed by a grid is dependent on grid design. The percentage of investigations that are not cases is dependent on prevalence of syphilis among reactors. In areas with moderate to high prevalence (>10%), use of certain grids will lead to missed cases, whereas in low prevalence areas (<10%) grids can reduce the percentage of unnecessary investigations.

  22. Implications • Grid evaluation should include the following: • Grids should be designed to minimize cases missed • Percent of non-productive investigations should not be a focus of grid design • Limited resources driving grid design can lead to missed cases • As yet no guidance on what percentage of cases missed is “acceptable” - Determination of grid design (inclusive vs. exclusive) - Calculation of syphilis prevalence among reactors

  23. Acknowledgements ATPM CDC Vera Schomer Josh Schaffzin Emily Koumans Richard Kahn Lauri Markowitz Catherine McLean Jim Braxton Gabriela Paz-Bailey Thanks to Charlotte Kent, Robert Kohn, Anne Spalding, Elizabeth Mangiamelli, Chris Freeman, Dacid Lundberg, Josephine Ford Michael Whelan, Kathy Middleton, Mary Kay Schuknecht, John Thilges, Jim Braxton

  24. Group A Group B Group C Group D Group E 260 846 196 124 347 18-64 9-75 13-76 12-52 18-62 36.0 34.9 36.9 34.9 23.1 126 (49) 576 (68) 62 (32) 54 (42) 246 (71) 134 (51) 270 (32) 134 (68) 74 (58) 101 (29) 47 19 9 7 0.9 8 9 10 NA 0.6 Reactor Grid Evaluation Group Demographics Reactors Age Range Mean Gender Male (%) Female (%) Dx Early (%) Late (%)

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