Health Disparities Among People Infected With Influenza, Rhode Island, 2013-2018.

Abstract

Health disparities are associated with poor outcomes related to public health. The objective of this study was to assess health disparities associated with influenza infection based on median household income and educational attainment. We geocoded people with documented confirmed influenza infection by home address to identify the US Census 2010 tract in which they lived during 4 influenza surveillance seasons (2013-2014, 2015-2016, 2016-2017, and 2017-2018) in Rhode Island. We dichotomized influenza as severe if the person with influenza infection was hospitalized (ie, inpatient) or as nonsevere if the person was not hospitalized (ie, outpatient). We examined 2 socioeconomic factors: median household income (defined as low, medium low, medium high, and high) and educational attainment (defined as a ratio among people who completed <high school, high school, some college, or ≥bachelor's degree). We calculated relative rates (RRs) to determine the associated level of risk for each socioeconomic factor. The incidence of influenza per 100 000 person-years was significantly higher in populations with low vs high median household income (620 vs 303; P < .001) and in populations with low vs high educational attainment (583 vs 323; P < .001). The RR of a severe infection in the quartile with the lowest educational attainment (0.57) was significantly higher than the RR in the other 3 quartiles of educational attainment (range, 0.36-0.39; P = .01). However, the RR of a severe infection was higher in the 3 quartiles of median household income (range, 0.38-0.40) than in the quartile with the lowest median household income (0.29). People in Rhode Island with a lower socioeconomic status are at greater risk of an influenza infection than people with higher socioeconomic status. The reasons for these disparities require further investigation.