Issue 14 - August 2003 : INFECTION CONTROL PRACTITIONERS INVALUABLE IN THE SYNDROMIC SURVEILLANCE PROCESS

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INFECTION CONTROL PRACTITIONERS INVALUABLE IN THE SYNDROMIC SURVEILLANCE PROCESS
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During the recent Association for Professionals in Infection Control and Epidemiology (APIC) annual conference in San Antonio, Dr. Tracy Gustafson, VP of Research and Development, ICPA Inc, presented his findings in a pilot study of syndromic surveillance involving a large urban Texas hospital. In presenting his findings, he emphasized the importance of the Infection Control Practitioner in the syndromic surveillance process.

Dr. Gustafson began by discussing what he sees as the primary objectives of syndromic surveillance. These are to: detect bioterrorism quickly; recognize pseudo-epidemics to avoid public panic; and to improve routine public health surveillance of reportable diseases and outbreaks.

Some people include laboratory-based surveillance as a type of syndromic surveillance - it is not. By the time a culture is reported you know the diagnosis. So laboratory tests are really a form of "diagnostic surveillance."
Laboratory-based surveillance is useful, but "syndromic surveillance" of emergency room visits is better because:
1) Lab tests are expensive and take time.
2) It's impossible to test everyone for every disease.
3) Sometimes, no laboratory test is readily available (e.g. SARS).
4) Emergency room data is available sooner, and at less expense.
In summary, Dr. Gustafson believes that syndromic surveillance of emergency room data provides a more complete look at the public's health at any point in time.

Given that you want to collect data about emergency room visits, how should you go about it? Manual data entry into a computer or web-site is slow and time consuming, possibly requiring dedicated ER staff. In addition, some software requires staff to decide which syndrome to place the patient in - and different staff might categorize patients differently. For these reasons, importing text data from emergency room or billing software is clearly preferred. Software that uses natural language processing to parse text data entered about the patient such as chief complaint, diagnosis, or electronic medical record data into syndrome categories is efficient and surprisingly effective.

In the pilot study, 115,000 records of emergency room patients seen between October 2001 and September 2002 were analyzed using the RedBat(r) software, a natural language processor. Of these records, 24% were trauma, 7.6% were psychiatric, and 2.7% were obstetric cases. The remaining cases had medical complaints, and were included in the syndromic analysis.

One of the first surprises was how much you can learn from a single emergency room. Even if a local health department can only get data from one emergency room, it provides a window onto the community as a whole. In the data analyzed for the pilot study, several outbreaks and pseudo-outbreaks were seen. Between Oct 12, 2001 and Nov 18, 2001, a pseudo-outbreak of Anthrax occurred, spurred by the fear following 9/11 and the Anthrax cases in Florida and Washington. In addition, in late July a pseudo-outbreak of West Nile encephalitis occurred, brought about by fear after the first human case was reported in Texas. Of course, influenza season was readily identified by respiratory syndrome, and several real food-borne outbreaks were visible from one-day increases in emergency rooms visits for GI complaints.

However, the emphasis of Dr. Gustafson's talk was on the benefits of syndromic surveillance for individual facilities and the need for Infection Control Practitioners to be involved. Syndromic surveillance provides excellent data about reportable diseases coming in from the community. In the pilot study, 1.4% of the emergency room visits mentioned a reportable disease, and 34% of these were sick enough to be hospitalized. ICPs benefit from a daily list of such visits, so they can ensure proper isolation and reporting of these cases to the local health department. In addition, a thoughtful review may identify opportunities for improvement and/or ways to save money. The ICPs involved in the pilot study quickly noticed a problem when they saw how many PPD conversions were going to the emergency room for chest x-rays, instead of being referred directly to the TB clinic.

In addition, Infection Control Practitioners have a responsibility to assist bioterrorism surveillance. ICPs should be members of the Bioterrorism Task Force in their facility and the community, and should be involved in the process of selecting syndromic surveillance software. Once purchased, Infection Control Practitioners, with their training in epidemiology and infectious diseases, are the best equipped to analyze data. Dr. Gustafson emphasized that computers will never replace the knowledge and experience of a well-versed ICP.

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