The benign nature of acute dengue infection in hospitalized older adults in Singapore

Objectives: In Singapore, dengue primarily affects adults. This study aimed to determine if older dengue patients in Singapore have greater morbidity and mortality. Methods: All laboratory diagnosed dengue patients admitted to Tan Tock Seng Hospital in 2004 were retrospectively reviewed. Cases were re-classified into dengue fever and dengue hemorrhagic fever based on World Health Organization criteria. Demographic, clinical, laboratory, and outcome data of patients aged >= 60 years and <60 years were collected. Results: Of 1971 laboratory confirmed dengue cases, 66 were aged >= 60 years. Older patients were significantly less likely to be male (44% vs. 64%), and more likely to have diabetes (17% vs. 2%), hypertension (48% vs. 4%), ischemic heart disease (6% vs. 0.1%), hyperlipidemia (18% vs. 1%), and secondary dengue infections (64% vs. 34%). Clinical features were similar except older patients were significantly less likely to report fever (92% vs. 99%), or have leukopenia (32% vs. 51%) or hemoconcentration (0 vs. 5%) on admission. Older patients had similar dengue hemorrhagic fever, bleeding, hypotension, severe thrombocytopenia, and elevated transaminase rates. Length of hospital stay, risk of intensive care unit admission, and outcome of death were not statistically different. Conclusions: Despite greater co-morbidity and secondary dengue infection, older dengue patients in Singapore did not have greater morbidity or mortality. (C) 2009 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.