Quality of Life of Dengue Patients Lucy C. S. Lum,* Jose A. Suaya, Lian H. Tan, Binod K. Sah, and Donald S. Shepard Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia; Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts Abstract. Although the disease burden of dengue is increasing, the impact on the quality of life (QoL) has not been investigated. A study to determine the QoL of confirmed dengue patients using the EuroQol visual thermometer scale was carried out at the University Malaya Medical Center. Of the 207 participants, 40% were ambulatory and 60% were hospitalized. Of eight health domains, 6.2 and 5.0 domains were affected in the hospitalized and ambulatory cohorts, respectively (P < 0.001), with cognition and interpersonal activities affected most. All patients experienced a drastic decrease in their QoL from the onset of symptoms. The QoL deteriorated to the lowest point (40% of healthy status) between the third and seventh days of illness. The duration of impaired QoL (9 days for ambulatory or 13 days for hospitalized patients) was longer than the duration of fever (5 and 7 days, respectively). Symptomatic dengue has major effects on patients’ health. INTRODUCTION With mosquito vectors and dengue viruses expanding to previously unaffected areas, dengue is becoming the world’s most important arthropod-borne viral infection. A disease of major public health concern, with a global annual average of 829,000 cases and 1,600 deaths officially reported to the World Health Organization 1 (WHO) during the period 2000– 2004. However, because dengue is underreported in many countries, 2 researchers have speculated that dengue may cause between 50 and 100 million cases annually, 3,4 thousands of hospitalizations, and about 20,000 deaths each year. 5 In Malaysia, dengue was first documented in 1902 and made reportable in 1971. 6 After the first outbreak of dengue hemorrhagic fever (DHF) in 1962, 7 major dengue outbreaks occurred every four years until 1992; since then the disease became endemic with yearly and frequent outbreaks. 8 This situation reflected a phenomenon throughout Southeast Asian cities in which environmental disruption and demo- graphic changes favored proliferation of the mosquito vectors and intense viral transmission, leading to hyperendemicity of dengue and increased incidence of the more severe form (DHF). Malaysia’s reported incidence of dengue has re- mained high, with an average of 125 to 150 per 100,000 people annually from 2002 to 2006, and the total number of reported cases increasing from approximately 27,000 in 1998 to almost 40,000 in 2005. Most cases were from urban areas. 9 After several decades of dengue in the urban areas of Ma- laysia, an epidemiologic shift in peak age incidence of dengue progressed from primarily pediatric ages to predominantly young adults in the 1980s. The proportion of cases  15 years of age in Malaysia increased from 35% in 1975 to 57% in 1982 8 and to 78% in 2005. 9 The proportion of dengue-related deaths in persons  15 years of age in Malaysia similarly increased from 59% in 1996 to 77% in 2005. The phenom- enon of predominantly adult dengue population has also been observed in Singapore 10,11 and Taiwan. 12 Other countries that have reported increased dengue infection in adults include Thailand, 13 Nicaragua, 14 and Sri Lanka, 15,16 but not to the same level as that in Malaysia, Singapore, and Taiwan. Age-related differences in dengue severity and the charac- teristics of dengue in the adult population were addressed in reports of cases in Thailand 13 and Nicaragua. 14 The increas- ing incidence of dengue in older children and adults in Ma- laysia presents an important opportunity to increase the un- derstanding of the illness from the patient’s perspective and the impact on his or her physical and mental health. Most studies assessing quality of life (QoL) focus on chronic ill- nesses. The acute illness experienced by dengue patients, al- though of short duration and not always life-threatening, could have an important impact on the patients’ daily activi- ties, social function, and emotional well-being. 17,18 Although some dengue studies have examined overall QoL, 19 to our knowledge, this is the first study to examine daily QoL in dengue patients during the entire illness episode. The data for this study came from a prospective study of the overall effect of dengue illness in the Klang Valley, the region of Malaysia from which most dengue cases are re- ported. The study included both children and adults treated in either ambulatory or hospitalized settings in a major teaching hospital of Malaysia. METHODS Study population. Of Malaysia’s 2005 population of 25.4 million persons, approximately 5.6 million live in Klang Val- ley where this study was conducted. The study was organized to enroll up to six patients per week recruited from the out- patient or inpatient care at the University Malaya Medical Center. The recruitment period was from December 2004 through December 2005. Selected patients or legal surrogates (when a patient was a child) were invited to participate in this study and a signed informed consent was obtained. Research instruments. A standardized structured patient survey was developed, piloted, and translated into Malay. It included questions about demographic characteristics of the patient and other household members, as well as relevant clinical characteristics of the illness episode and its effects on health status. The QoL assessment was made using the visual thermometer-like scale (visual analog scale) with 0 represent- ing the worst imaginable health state and 100 denoting best health state from EuroQol, a standardized instrument for valuing health-related QoL. 20 The interviewer showed the participant the thermometer-like scale on the day of enroll- ment and asked to indicate their level of health by drawing a * Address correspondence to Lucy C. S. Lum, Department of Pedi- atrics, Faculty of Medicine, University Malaya, Kuala Lumpur, Ma- laysia. E-mails: lumcs@ummc.edu.my and lucylum@gmail.com Am. J. Trop. Med. Hyg., 78(6), 2008, pp. 862–867 Copyright © 2008 by The American Society of Tropical Medicine and Hygiene 862