Abstract 4079: Electronic Biosurveillance for Trends in Circulatory Disease-Related Outpatient Service Utilization among Veterans Following Hurricane Katrina in 2005
Objective: To demonstrate the feasibility of using the Centers for Disease Control and Prevention (CDC) syndromic surveillance initiative (BioSense) for monitoring trends in service utilization for chronic diseases, in the event of a public health emergency.
Methods:The Veterans Health Administration (VHA) electronically transmits non-identifiable data, including diagnostic, procedural and demographic information, on every out-patient encounter to CDC’s BioSense initiative. Data for 7/31 through 8/29, 2005 (the date Hurricane Katrina struck the Gulf Coast), were compared with data for 8/30 through 9/30, 2005. Trends among patients with residential zip codes within hurricane affected areas (HAA) were compared with the rest of the country (Non-HAA). As patient identifiers are facility-specific, visits with no previous occurrence of an identifier within the preceding 12 months were assumed to be new registrations or first visits and were counted for every facility in the US. Diagnostic codes (ICD9-CM) associated with first visits were compared between the two periods for HAA and Non-HAA using both total number of diagnoses and unique visits as denominators.
Results: New registrations in HAA increased from 1630 to 6341 (from pre- to post-hurricane periods) compared to an increase from 44,8028 to 454849 for persons from non-HAA. The relative increase was significantly greater in HAA than non-HAA (OR 3.8 [CI 3.6–4] p<0.0001). New visits in HAA, were associated with 3790 and 12082 ICD9 CM codes in pre- and post-hurricane periods, respectively. Circulatory disorders (ICD9 390–459) were recorded 712 times (19% of total diagnoses and 44% of visits) in the pre-hurricane period compared to 3004 times in the post-hurricane period (25% of total diagnoses and 47 % of total visits). Among these 3004 diagnostic codes, the most prevalent (68%) was hypertensive disorders.
Conclusion: Outpatient service utilization post-hurricane Katrina increased significantly for hypertension and other circulatory disorders in hurricane affected areas. These findings demonstrate feasibility of the BioSense data for monitoring changes in chronic diseases and may prove valuable for informing future efforts in clinical and public health preparedness and emergency response.