“CDC Wonder” database keeps us wondering about actual Lyme stats
Pat Smith is the President of the Lyme Disease Association and was recently named to the federal Tick-Borne Disease Working Group. The following blog is re-published from the LDA website.
By Pat Smith
The Lyme Disease Association (LDA) reports that the total number of CDC reported 2016 Lyme cases are now available. Never saw them? Not surprising. In the past, the CDC consistently reported Lyme numbers on a weekly basis, as they do with the other reportable diseases in its MMWR Report, which is published weekly. The last weekly case numbers reported, however, were reported one year ago for 2016.
The CDC annual year end summary of reported Lyme case numbers in MMWR–confirmed, probable, and total–were consistently reported in the past about each 3rd week of August for the preceding calendar year. The past two years, that system has changed. In fact, the 2016 numbers came out in November 2017, and they are now very difficult to locate. Thinking I had missed them, LDA wrote and asked CDC at the end of October when/where they were to be published, as the CDC website message about new reporting was unclear about that issue. CDC sent LDA two links when they came out in November.
In the summer, the LDA had asked CDC informally in a phone call why the weekly numbers were missing. CDC indicated it no longer publishes the weekly numbers due to states saying it was too confusing, and they did not want them published, and The Council of State & Territorial Epidemiologists (CSTE) really had control over what is published in MMWR. None of that made sense to me at the time, and it still does not make sense, and no other diseases were affected by this change in practice.
Some questions about the new reported Lyme data include why is the state of Hawaii no longer listed as N, not reportable, as it has been in the past, but only as 0 cases? Big difference between the state not reporting a disease and the CDC indicating there were 0 cases, although there could be 0 cases. Why are New York City numbers broken out from New York State numbers in one area and combined in another? Why has the State of New York never had a note on the CDC report indicating that a huge % of its counties are not even included in CDC reported numbers, a question I have posed to CDC in the past.
The LDA on its NY case map indicates “In 2015, 25 NY counties used a sampling method to determine Lyme disease case numbers. The Council of State & Territorial Epidemiologists (CSTE), charged with surveillance, does not allow CDC to include those estimated numbers to be reported by CDC in the national counts. Thus, NY State had 8,272 Lyme cases including those 25 county numbers by State count, but CDC was only able to report nationally 4,314 Lyme cases for the State of New York.” CDC could use a short note to indicate that only xx counties are represented in its reported case numbers for New York. This omission of reporting at least 25 NY counties in a high incidence state affects the entire total case numbers for the US, plus it can influence policy in New York if those policy makers do not understand the system.
The CDC has a totally new system (new MMWR mechanism) in place for the final numbers, called CDC Wonder. That name seems appropriate as this whole issue leaves me wondering why we even have a Lyme surveillance system that is highly inaccurate, beginning with the surveillance criteria, which CDC disclaims responsibility for—CSTE is responsible. The CDC Lyme surveillance system has already had a huge impact on patients’ access to care, another issue for another discussion. Why did CDC change the reporting system to one that is user unfriendly, did not fix some of the issues the old one had which carried over, and perhaps created some new ones?
2016 Final CDC Numbers
The three states with the highest Lyme case numbers are the same as in 2015, from the Mid-Atlantic region: Pennsylvania, New Jersey and New York, the latter clinging to third place despite at least 25 of its counties not included in the reporting. Also note, Massachusetts, often in the top five states in the US in Lyme cases, is not in the top 15. The CDC told the LDA that Massachusetts has taken a new approach to surveillance and we would need to talk to Massachusetts for details.
The LDA has ranked the top 15 states based on the 2016 CDC Lyme case number summary. The chart below has the top 15 states ranked in order of highest to lowest case numbers, followed by the CDC reported Lyme case number, and then the number adjusted x10 for underreporting.
Links CDC gave to LDA:
https://www.cdc.gov/lyme/stats/index.html or you can access them through the new MMWR mechanism (go to the to table 2i at the following link) https://wonder.cdc.gov/nndss/nndss_annual_tables_menu.asp
Lyme Total Cases 2016 US 36,429——————————————————364,290
LDA NOTE “In 2015, 25 NY Counties used a sampling method to determine Lyme disease case numbers. The Council of State & Territorial Epidemiologists (CSTE), charged with surveillance, does not allow CDC to include those estimated numbers to be reported by CDC in the national counts. Thus, NY State had 8,272 Lyme cases including those 25 county numbers by State count, but CDC was only able to report nationally 4,314 Lyme cases for the State of New York.” 2016 county number used as yet unavailable.
2016 number of counties used for reporting as yet unavailable. However, in 2016, NYS reported a total of 7,543 cases, of which CDC was able to report 3,882.
LDA Chart of all states in alphabetical order for 2016 final reported case numbers