Although hospitalized older adults are at an increased risk for influenza morbidity and mortality, they are tested for the virus less often than their younger counterparts, according to a study published in the Journal of the American Geriatrics Society.
The investigators conducted a prospective study at 1 academic and 3 community hospitals in Davidson County, Tennessee to examine the factors linked to provider-ordered influenza testing in hospitalized adults. They compiled information on patient demographics, symptoms, and provider-ordered testing with the use of questionnaires and chart reviews. Laboratory-based surveillance was performed using reverse-transcriptase polymerase chain reaction — the gold standard for influenza diagnosis.
A total of 1422 adults at least18 years old with acute respiratory illness and nonlocalizing fever participated in the study. Characteristics of participants with and without provider-ordered influenza testing were compared via Wilcoxon tests, Pearson’s chi-square tests, and multivariable regression models.
Overall, 28% of participants (399 of 1422) received provider-ordered influenza testing. Patients who were tested were significantly younger than patients who were not tested (58±18 years vs 66±15 years, respectively; P <.001) and were significantly more likely to have an influenza-like illness (71% vs 49%, respectively; P <.001).
Patients who had received provider-ordered influenza testing were significantly more likely to have presented with fever (73% tested vs 44% not tested; P <.001) and with influenza-like illness (71% tested vs 49% not tested; P <.001). The mean age of patients who presented with influenza-like illness who received provider-ordered influenza testing was 55±10 years vs 63±9 years (P =.027) in patients who did not receive provider-ordered influenza testing. Moreover, the prevalence of influenza-like illness increased with younger age (≥65 years: 48%; 50-64 years: 60%; 18-49 years: 63%). In individuals with study-confirmed influenza, influenza-like illness was reported less often in older adults (≥65 years: 74%; 50-64 years: 83%; 18-49 years: 81%).
Of patients who received care in the single academic hospital, 41% (231 of 561) had received provider-ordered tests for influenza, compared with only 29% (168 of 861) of patients who received care in one of the three community hospitals.
The investigators concluded that no single factor can be attributed to the decrease in provider-ordered influenza testing in older adults. Future research is warranted in order to enhance clinician understanding of the challenges involved in identifying influenza in older adults, thus improving diagnosis and treatment in this vulnerable population.
Hartman L, Zhu Y, Edwards KM, Griffin MR, Talbot HK. Underdiagnosis of influenza virus infection in hospitalized older adults [published online January 17, 2018]. J Am Geriatr Soc. doi:10.1111/jgs.15298