Performance of the Universal Vital Assessment (UVA) mortality risk score in hospitalized adults with infection in Rwanda: A retrospective external validation study

Abstract

Background: We previously derived a Universal Vital Assessment (UVA) score to better risk-stratify hospitalized patients in sub-Saharan Africa, including those with infection. Here, we aimed to externally validate the performance of the UVA score using previously collected data from patients hospitalized with acute infection in Rwanda.

Methods: We performed a secondary analysis of data collected from adults ≥18 years with acute infection admitted to Gitwe District Hospital in Rwanda from 2016 until 2017. We calculated the UVA score from the time of admission and at 72 hours after admission. We also calculated quick sepsis-related organ failure assessment (qSOFA) and modified early warning scores (MEWS). We calculated amalgamated qSOFA scores by inserting UVA cut-offs into the qSOFA score, and modified UVA scores by removing the HIV criterion. The performance of each score determined by the area under the receiver operator characteristic curve (AUC) was the primary outcome measure.

Results: We included 573 hospitalized adult patients with acute infection of whom 40 (7%) died in-hospital. The admission AUCs (95% confidence interval [CI]) for the prediction of mortality by the scores were: UVA, 0.77 (0.68-0.85); modified UVA, 0.77 (0.68-0.85); qSOFA, 0.66 (0.56-0.75), amalgamated qSOFA, 0.71 (0.61-0.80); and MEWS, 0.74 (0.64, 0.83). The positive predictive values (95% CI) of the scores at commonly used cut-offs were: UVA >4, 0.35 (0.15-0.59); modified UVA >4, 0.35 (0.15-0.59); qSOFA >1, 0.14 (0.07-0.24); amalgamated qSOFA >1, 0.44 (0.20-0.70); and MEWS >5, 0.14 (0.08-0.22). The 72 hour (N = 236) AUC (95% CI) for the prediction of mortality by UVA was 0.59 (0.43-0.74). The Chi-Square test for linear trend did not identify an association between mortality and delta UVA score at 72 hours (p = 0.82).

Conclusions: The admission UVA score and amalgamated qSOFA score had good predictive ability for mortality in adult patients admitted to hospital with acute infection in Rwanda. The UVA score could be used to assist with triage decisions and clinical interventions, for baseline risk stratification in clinical studies, and in a clinical definition of sepsis in Africa.

Fig 1. Flow diagram of participant inclusion in the external validation study of the UVA score in a cohort of patients admitted to hospital with acute infection in Gitwe, Rwanda.

Fig 2. Receiver operating characteristic curves for different mortality risk scores used to predict mortality in adult patients admitted to hospital with acute infection in Gitwe, Rwanda.

Fig 3. The frequency and associated case fatality rate of UVA score risk categories (low 0–1, medium 2–4, high >4) of adult patients admitted to hospital with acute infection in Gitwe, Rwanda.

Fig 4. Odds ratios with 95% confidence intervals for in-hospital mortality associated with medium (2–4) and high (>4) risk UVA score categories compared to the low (0–1) risk UVA score category for adult patients admitted to hospital with acute infection in Gitwe, Rwanda.