RESUMO
Dengue is classified as an endemic infectious disease, which is transmitted by Aedes mosquitos. Kinetic studies, which monitor the viral load of the disease, have been the mainstay for several decades in humanity's quest to control this disease. Our study aims to systematically evaluate the usage of different timing systems in dengue kinetic studies. A search in nine electronic databases and manual search of reference and citation lists were conducted to find relevant studies. A quality assessment using the National Institute of Health tools for observational cohort and cross-sectional studies was performed. The protocol was registered in PROSPERO with number CRD42018086435. As results, among included 87 studies, 71 studies (81.6%) use a timing system which is based on the day of illness onset, of which, 11 studies designate the day of illness onset as "day 0â³ (type 1A) while 60 studies designate it as "day 1â³ (type 1B). Only ten articles (11.5%) designate the day of defervescence as "day 0â³, the day before and after defervescence as "day -1â³ and "day +1â³, respectively. Four articles (4.6%) use a timing system based on the day of hospital admission. Lastly, two studies (2.3%) designate the day of hemorrhagic manifestation as "day 0â³ and two studies (2.3%) designate the day of pharmacological treatment as "day 1â³. Therefore, the timing system which designates the day of illness onset as "day 1â³ (type 1B) was most commonly used. Inconsistent definitions of "day 0â³ and "day 1â³ may lead to disparities in results across the studies and may have a negative impact on treatment guidelines implementation.