A Prospective Case Control Study To Evaluate The CRADLE Vital Signs Alert Device For Detection Of Patients With Clinically Important Malaria In Refugee Settings
Abstract Background: Malaria is a significant threat to refugee populations. Bidibidi Refugee Settlement, Northern Uganda hosts 223 000 of Uganda’s 1.4 million refugees, vulnerable to malaria due to crowded conditions and limited access to preventative measures and health care. Early detection and referral of suspected malaria cases is key to reducing associated morbidity and mortality. We therefore aimed to evaluate shock index (heart rate/ systolic blood pressure), calculated by the CRADLE Vital Signs Alert (VSA) device, an easy-to-use blood pressure and heart rate monitor, for detection of malaria as grounds for whether the device could be used for low cost identification and referral of patients by non-medically trained Village Health Team workers (VHTs).Methods: CRADLE VSA devices and related training were delivered to all health facilities and VHTs in Bidibidi Refugee Settlement from April to August 2018. CRADLE VSA readings was performed as part of routine patient assessment. CRADLE VSA data (blood pressure, heart rate) and assigned diagnoses were collected from health facility data record books and shock index calculated for each case. Cases were grouped into predefined disease categories, including malaria and severe malaria. A control group consisted of refugees undergoing asymptomatic screening using the CRADLE VSA. Average shock index was calculated for cases and controls and prespecified disease categories, and predictive statistics to evaluate shock index for prediction of malaria and severe malaria.Results: Five hundred and eighty-seven CRADLE VSA devices were delivered. Malaria accounted for 26% (915/3577) of cases and had the highest shock index compared to other disease categories. Positive likelihood ratios for shock index using a threshold of greater than or equal to 0.9 were 5 and 11 for malaria and severe malaria respectively.Conclusion: Malaria accounted for over a quarter of cases. Positive likelihood ratios indicated that patients with shock index greater than or equal to 0.9 were 5 and 11 times more likely to be suffering from malaria and severe malaria respectively, indicating that the CRADLE VSA could be used by non-medically trained VHTs to identify patients likely to have malaria, and those most at risk of severe disease needing urgent referral. Trial Registration: This is an observational study and therefore does not have or require a trial registration. Appropriate permissions were granted by UN Refugee Council, Ministry of Health and Office of the Prime Minister.