A 15-year review of dengue hospitalizations in Singapore: Reducing admissions without adverse consequences, 2003 to 2017

Objectives Since the 1990s, Singapore has experienced periodic dengue epidemics of increasing frequency and magnitude. In the aftermath of the 2004-2005 dengue epidemic, hospitals refined their admission criteria for dengue cases to right-site dengue case management and reduce the burden of healthcare utilization and negative outcomes. In this study, we describe the national trends of hospital admissions for dengue and disease severity in terms of length of stay (LOS), admission to the intensive care unit (ICU) and death in hospital, and case fatality rate (CFR) in Singapore. Methods We conducted a retrospective study of notified cases and laboratory confirmed dengue patients admitted to all public and private hospitals between 2003 and 2017. Case notifications for dengue and hospitalization records were extracted from national databases. Results The proportion of dengue cases hospitalized was lower in recent years; 28.9% in the 2013-2014 epidemic, compared to 93.2% in the 2004-2005 epidemic, and 58.1% in the 2007 epidemic. Median LOS remained stable over the years; overall LOS was 3 to 4 days and ICU stay was 2 to 3 days. Less than 2% of hospitalized patients were admitted to the ICU. Overall CFR was low and remained below 0.5%. The proportions of dengue cases hospitalized and patients admitted to the ICU were highest in the elderly aged 65 years and older. Conclusions While the proportion of dengue cases hospitalized saw a drastic decline due to more selective admission criteria, there was no concomitant increase in adverse outcomes, suggesting that admission criteria were appropriate to focus on severe dengue cases. Further studies are needed to optimize dengue management in older adults who are more likely to be hospitalized with greater disease severity, given the higher proportions of hospitalizations and severe disease among older adults. Author summary Following the review of hospital admission criteria for dengue cases in the aftermath of the 2004-2005 dengue epidemic in Singapore, the proportion of dengue cases hospitalized plummeted from 72.6% in 2006 to the nadir of 25.6% in 2014. There was no concomitant increase in adverse outcomes as a result of the more selective admission criteria. Median length of stay remained stable over the years; overall stay was 3 to 4 days and intensive care unit (ICU) stay was 2 to 3 days. Among hospitalized dengue patients, less than 2% were admitted to the ICU. Overall case fatality rate was low and remained below 0.5%. Elderly patients aged 65 years and older constituted the highest proportions of dengue cases hospitalized and patients admitted to the ICU.