Dengue haemorrhagic fever (DHF) is a mosquito-borne infection caused by the dengue virus. One of the hallmarks of DHF is thrombocytopenia, defined by a thrombocyte level below 150 000/ml of blood or the 2.5th percentile (Izak and Bussel, 2014). The dengue virus triggers thrombocytopenia through hypoplasia of the bone marrow, heightened platelet destruction due to consumptive coagulopathy, and lysis due to the dysregulated complement immune system (Azeredo et al., 2015). Patients with low thrombocyte levels easily progress to dengue shock syndrome or even death.

DHF is most likely to occur in tropical and humid countries, such as Indonesia and its surrounding countries. In tropical countries, it has a comparable disability-adjusted life years to other infectious diseases (e.g., hepatitis B and tuberculosis) (Kementerian Kesehatan Republik Indonesia, 2021). An aggregate data from 2015 to 2020 of DHF portrayed an annual case of 118 000 coupled with an 877-death rate, making Indonesia the second global leading country with DHF just below Brazil (Setiawan et al., 2023). Currently in March 2024 there is an outbreak of DHF in Indonesia, where there are 16 000 active cases across 213 cities with 124 mortalities (Ditjen P2P, 2024). That is only counting the reported ones, as the surveillance system is still poor (Bhatt et al., 2013).

The use of guava (Psidium guajava) for treating dengue fever has been a topic of interest in scientific research owing to its potential benefits at the thrombocyte level. Guava contains tannin and flavonoids such as quercetin, morin, and vitamin C, which have been shown to play a role in the production of platelets and inhibit the replication of the dengue virus (Darmaningrat, 2023). Recent research had established the capacity of morin compound to suppress dengue virus replication and cytotoxicity (Maharani et al., 2020). Guava itself is a common and easy to find produce with 239.407 tones of production annually sold at IDR 5 000–20 000/kg (US$ 0.3–1.3) (Datundugon et al., 2020). However, some academics and ministers have labelled this as disinformation, where they cited that guava only strengthen the body immune through vitamin C while the thrombocyte improvement is only due to the disease progression (InfoSehat, (2019, KOMINFO, 2019).

This meta-analysis summarises the role of guava in increasing thrombocyte counts in Indonesian patients with DHF. We used a control group comparison to ensure an independent effect, separate from natural disease progression.