The impact of blood pressure indicators and shock indices on hazard of complicated dengue in hospitalized adults with dengue infection

Blood pressure monitoring is crucial for early detection of complicated dengue. We investigated the association between blood pressure indicators and complicated dengue hazard over the course of dengue hospitalization in a well-characterized dengue cohort. This study involved 4789 adult dengue patients hospitalized between 2005 and 2008 who did not have complicated dengue (defined as dengue haemorrhagic fever and/or severe dengue) initially. Cases (n = 689) included patients who progressed to complicated dengue during hospitalization, while controls were patients who did not (n = 4100). We used Cox models with time-dependent covariates to estimate hazard ratios for blood pressure indicators' impact on complicated dengue hazard. Additionally, we employed the overlap weighting approach to balance clinical characteristics and conducted subgroup analyses based on age, sex and warning signs. Results indicated that modified shock index (MSI) $\ge$0.8 was associated with a higher time-averaged hazard in the main cohort (HR: 1.72 [1.36, 2.19], p-value: <0.01). Shock index (SI) ≥0.7 also indicated increased hazard in the main cohort (HR: 1.64 [1.37, 1.95], p-value: <0.01) and among patients without mucosal bleeding (HR: 1.42 [1.19, 1.72], p-value: <0.01). A DBP <60 mmHg led to higher hazards of complicated dengue (HR: 1.45 [1.23, 1.72], p-value: <0.01) in the main cohort. In conclusion, DBP <60 mmHg, shock index $\ge$0.7 and modified shock index $\ge$0.8 may be reliable predictors for complicated dengue during hospitalization in adult dengue patients. Clinicians should consider these indices during patient assessment.