When the nation began hearing news about the influenza outbreak last fall, it came as no surprise to Ed Carubis. As CIO and associate commissioner of the New York City Department of Health and Mental Hygiene (DHMH), Carubis had access to an IT system that warned him and his staff weeks prior to the outbreak.
"We predicted the flu outbreak two weeks in advance of any traditional surveillance methods," said Carubis. "That two-week jump was very important -- it allowed us to notify the medical provider community and allowed them to take action to encourage those at risk to get a flu vaccine."
Carubis and his staff use a combination of information systems to keep them abreast of public health concerns throughout New York City. Chief among these is a syndromic surveillance system designed to provide early detection of disease clusters and serve as an early warning system for terrorism events involving biological, chemical or radiological agents. "During outbreaks, time is of the essence in the ability to control, mitigate or respond to an event," said Carubis.
Historically city disease and illness surveillance efforts relied on patient visits to doctors' offices and lab tests, but that often meant days or weeks before a pattern was detected. "Traditional public health reporting has a built-in delay between when a person first gets sick, and that diagnosis and reporting," said Rick Heffernan, director of data analysis in the bureau of communicable disease at the DHMH. "Syndromic surveillance is trying to move further upstream to capture some of the data collected early in a person's illness."
New York's syndromic surveillance system uses a wide variety of data sources -- 911 calls, emergency room data, pharmacy sales data -- to rapidly detect increased reports that may indicate an outbreak. The system tracks the reports both geographically and by number of cases.
In 1999, the DHMH began examining 911 call data. "We believed there were certain 911 calls that could be indicative of an event that's occurring, from a food-borne illness all the way up to a bio-terrorism event," said Carubis. "We were receiving 911 call data from the fire department routinely anyway, so it was an easy way to start."
After Sept. 11, the DHMH looked at expanding the system, and started working with hospitals that collect data electronically and tried convincing them to share the information. "We didn't want to make any additional work for the individuals in the emergency rooms," Carubis said. "So it's very much been an IT-to-IT discussion of how to exchange information between systems."
Complaint data from patients at 40 different hospitals in the city now comes to the DHMH automatically through the syndromic surveillance system, which uses sophisticated data-mining software to collect and analyze the information.
Next, the DHMH worked with major pharmacy chains to gather certain over-the-counter drug data. The department wanted to survey data on citizens who didn't feel bad enough to call 911 or go to the emergency room, but were feeling poor enough to visit the pharmacy.
Most recently, the DHMH worked with major New York City employers that operate electronic attendance systems, hoping to detect a large rise in absenteeism that could indicate a disease outbreak in the city.
Mining the Data
Once all data is collected from the various sources in different formats, it's merged and transformed into a common format. The DHMH then runs an analysis on the data, and the system alerts them to conditions that may indicate an outbreak. "We send the results of those analyses to a group of epidemiologists who decide whether or not it warrants a response," said Heffernan.
The epidemiologists form hypotheses about what may be occurring and determine the information needed to confirm their hypotheses. They then conduct interviews with patients