Dengue hospitalisations in Singapore: reducing the burden of epidemics on healthcare systems

Singapore has regularly faced outbreaks of dengue. Following a severe epidemic in 2005, authorities reviewed hospital admission criteria in a bid to reduce pressures on the healthcare system. In this Infectious Thoughts interview, we speak to Ms. Li Wei Ang, a principal medical statistician in the National Public Health and Epidemiology Unit at the National Centre for Infectious Diseases, Singapore, about recent research evaluating the impact of reduced hospital admissions for dengue over the last 15 years and whether this increased adverse consequences.

Dengue outbreaks cause a sharp and sudden burden on healthcare facilities in affected areas. What have been some of the trends in dengue hospitalisations in Singapore, where several severe outbreaks have occurred in recent decades?

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 hospitalised plummeted from 72.6% in 2006 to the nadir of 25.6% in 2014.

The proportion of dengue cases hospitalised was 28.9% in the 2013-2014 epidemic, compared to 93.2% in the 2004-2005 epidemic, and 58.1% in the 2007 epidemic.

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 hospitalised dengue patients, less than 2% were admitted to the ICU.

Which steps have authorities taken to support healthcare facilities and ease pressure from increased admissions?

The Singapore Ministry of Health (MOH) had appointed a dengue clinical workgroup to provide advice on clinical management. MOH sends out circulars to hospitals, government primary care clinics and medical practitioners to apprise them of the dengue situation during epidemic periods, and to provide periodic updates on guidelines for the management of dengue.

Dengue management in Singapore is guided by evidence-based practice. In 2008, the National Medical Research Council (NMRC) funded a flagship research grant on dengue research. This grant generated a plentitude of findings to support optimal clinical management of dengue patients; these included assessment of the utility of warning signs in the 2009 World Health Organization (WHO) recommendations for guiding hospital admission and predicting severe dengue, and investigation of the effectiveness of prophylactic platelet transfusion in the clinical management of thrombocytopenia in adults with uncomplicated dengue infection.

As it has been recognized that the majority of dengue infections result in relatively mild illness, primary care practitioners are actively engaged in diagnosis and clinical management of such cases. Most of the adults with uncomplicated dengue infection can be effectively and safely monitored as outpatients in the community.

What are the main consequences in terms of case intensity or even fatality of reducing hospital admissions for dengue cases?

While the proportion of dengue cases hospitalised has seen a drastic decline, there has been no concomitant increase in adverse outcomes (admission to ICU and deaths), indicating that patients with more severe dengue requiring inpatient care and monitoring are being accurately identified and appropriately referred and admitted.

Data on actual numbers of dengue cases, and particularly asymptomatic cases, remains sparse but research in this field is rapidly seeking to fills these gaps. How will better estimates of global dengue cases influence the recommendations from your work? Will this help to mobilise further resources and funding to the control and management of this disease?

Asymptomatic infection was not within the scope of this study. Our focus has been on individuals with symptoms of different degrees of severity. In this study, we pointed out the increase in the proportion of dengue cases hospitalised after the 2013–2014 dengue epidemic, which was likely contributed to by both an increased risk of disease among the older population as well as the inclusion of age ≥65 years as a specific indication for hospitalisation. This is a worrisome feature and there should be more funding to study the impact of dengue, particularly in older adults.