Characteristics of People Who Do Not Complete a Public Health Interview: An Assessment of Colorado Enteric Disease Surveillance Data.

Objectives: Although enteric disease case interviews are critical for control measures and education, not all case-patients are interviewed. We evaluated systematic differences between people with an enteric disease in Colorado who were and were not interviewed to identify ways to increase response rates and reduce biases in the surveillance data used to guide public health interventions.

Methods: We obtained data from the Colorado Electronic Disease Reporting System from March 1, 2017, through December 31, 2019. Among case-patients not interviewed and interviewed, we used univariate analyses to describe sociodemographic characteristics, timing of contact attempts, and effect of additional funding.

Results: As compared with case-patients who were interviewed, case-patients who were not interviewed were significantly more likely to be aged 18 to 39 years (35.7% vs 31.7%;  < .001); identify as male, Hispanic, or Black; be experiencing homelessness or hospitalization; reside in rural/frontier areas or an institution; or live in areas with lower levels of education, life expectancy, and income. Time to first contact attempt was longer for case-patients who were not interviewed than for those who were (mean days from specimen collection to first contact attempt, 9.8 vs 6.8;  < .001). Residing in a jurisdiction with additional funding for interviewing was associated with increased interview rates (87.7% vs 68.8%) and timeliness of public health report and first contact attempt (2.3 vs 4.4 days;  < .001).

Conclusion: Findings can guide efforts to improve response rates in groups least likely to be interviewed, resulting in reduced biases in surveillance data, better disease mitigation, and increased efficiency in case investigations. Timeliness of case interviews and additional funding to conduct case investigations were factors in increasing response rates.