Rapid Detection of Influenza Outbreaks in Long-Term Care Facilities Reduces Emergency Room Visits and Hospitalization: A Randomized Trial

Abstract

Objectives: To assess whether the use of rapid influenza diagnostic tests (RIDTs) for long-term care facility (LTCF) residents with acute respiratory infection is associated with increased antiviral use and decreased health care utilization.

Design: Nonblinded, pragmatic, randomized controlled trial evaluating a 2-part intervention with modified case identification criteria and nursing staff-initiated collection of nasal swab specimen for on-site RIDT.

Setting and participants: Residents of 20 LTCFs in Wisconsin matched by bed capacity and geographic location and then randomized.

Methods: Primary outcome measures, expressed as events per 1000 resident-weeks, included antiviral treatment courses, antiviral prophylaxis courses, total emergency department (ED) visits, ED visits for respiratory illness, total hospitalizations, hospitalizations for respiratory illness, hospital length of stay, total deaths, and deaths due to respiratory illness over 3 influenza seasons.

Results: Oseltamivir use for prophylaxis was higher at intervention LTCFs [2.6 vs 1.9 courses per 1000 person-weeks; rate ratio (RR) 1.38, 95% CI 1.24-1.54; P < .001]; rates of oseltamivir use for influenza treatment were not different. Rates of total ED visits (7.6 vs 9.8/1000 person-weeks; RR 0.78, 95% CI 0.64-0.92; P = .004), total hospitalizations (8.6 vs 11.0/1000 person-weeks; RR 0.79, 95% CI 0.67-0.93; P = .004), and hospital length of stay (35.6 days vs 55.5 days/1000 person-weeks; RR 0.64, 95% CI 0.0.59-0.69; P < .001) were lower at intervention as compared to control LTCFs. No significant differences were noted for respiratory-related ED visits or hospitalizations or in rates for all-cause or respiratory-associated mortality.

Conclusions and implications: The use of low threshold criteria to trigger nursing staff-initiated testing for influenza with RIDT resulted in increased prophylactic use of oseltamivir. There were significant reductions in the rates of all-cause ED visits (22% decline), hospitalizations (21% decline), and hospital length of stay (36% decline) across 3 combined influenza seasons. No significant differences were noted in respiratory-associated and all-cause deaths between intervention and control sites.

Keywords: Long-term care facilities; infection control; influenza; randomized controlled trial; rapid influenza diagnostic test.