Medicaid outpatient utilization for waterborne pathogenic illness following Hurricane Floyd

Flooding provides an opportunity for epidemics of waterborne viral, protozoan, or bacterial diseases to develop in affected areas. Epidemic levels of disease may translate into higher than average levels of health services use, depending in part on help-seeking behaviors. The authors investigated whether the flooding that occurred as a result of Hurricane Floyd in September 1999 was associated with an increase in outpatient visits for waterborne diseases among Medicaid enrollees in eastern North Carolina.

Using a difference-in-differences estimation technique, the authors examined the change in outpatient visits by North Carolina Medicaid enrollees for selected waterborne diseases following the hurricane. The study focused on counties with high concentrations of hog farming that were mildly/moderately or severely affected by the hurricane, using unaffected counties and the year before the hurricane as controls.

Small increases in Medicaid-covered outpatient visits were found in severely affected counties for two of the six pathogens selected for analysis, relative to unaffected counties. Larger increases in visits were found for nonspecific intestinal infections in both severely and moderately affected counties following the hurricane, relative to unaffected counties.

The large increase in visits for ill-defined intestinal infection is noteworthy. The relative lack of increase in visits with specific pathogenic diagnoses may be attributable, at least in part, to a number of factors, including incomplete diagnostic information provided by treating clinicians, low treatment-seeking behavior, and use of non-Medicaid-funded emergency services.