Indicators of Acute Kidney Injury as Biomarkers to Differentiate Heatstroke from Coronavirus Disease 2019: A Retrospective Multicenter Analysis

Abstract

Background: Coronavirus disease 2019 and heat related-illness are systemic febrile diseases. In the summer during the COVID-19 pandemic, a differential diagnosis between the two conditions is important. However, no studies have compared and distinguished heat-related illness from COVID-19. We aimed to compare the data between patients with early-stage heat-related illness and those with COVID-19.Methods: This retrospective observational study included 90 patients with early-stage heat-related illness selected from Heatstroke STUDY 2017-2019 (nationwide registries of heat-related illness in Japan) and 86 patients with laboratory-confirmed COVID-19 with complaints of fever or fatigue and were admitted to one of two hospitals in Tokyo, Japan.Results: Among vital signs, systolic blood pressure (119 vs. 125 mmHg, p = 0.02), oxygen saturation (98% vs. 97%, p < 0.001), and body temperature (36.6 vs. 37.6 °C, p<0.001) showed significant between-group differences for the heatstroke and COVID-19 groups, respectively. Numerous intergroup differences in laboratory findings were present, including white blood cell counts (10.8 vs. 5.2 × 10 3 /μL, p<0.001), creatinine (2.2 vs. 0.85 mg/dL, p<0.001), and C-reactive protein (0.2 vs. 2.8 mg/dL, p<0.001), although a logistic regression model achieved an area under the curve (AUC) of 0.966 4 4 using these three factors. A Random Forest machine learning model achieved accuracy, precision, recall, and AUC of 0.908, 0.976, 0.842, and 0.978, respectively. Creatinine was the most important feature of this model. Conclusions: Acute kidney injury was associated with heat-related illness, which could be key in distinguishing or evaluating patients with fever in the summer during the COVID-19 pandemic.

Wearing a face mask during controlled‐intensity exercise is not a risk factor for exertional heatstroke: A pilot study

“…The elderly are at an increased risk for heatstroke 1,2,18, . Therefore, further studies are necessary, particularly in monitoring exercise intensity.…”

“…Moreover, patients with COVID-19 commonly present with fever and hyperthermia, causing difficulties in distinguishing between heatstroke and these symptoms. 1,2 Thus, there is an urgent need to discuss the prevention of heatstroke during this pandemic.…”

“…Considering the significant amount of time an individual wears a mask, it is important to consider the balance between heat exhaustion prevention and daily life activity, and to ensure physical cooling to prevent heatstroke. Moreover, patients with COVID‐19 commonly present with fever and hyperthermia, causing difficulties in distinguishing between heatstroke and these symptoms 1,2 . Thus, there is an urgent need to discuss the prevention of heatstroke during this pandemic.…”

Heat stroke management during the COVID‐19 pandemic: Recommendations from the experts in Japan (2nd edition)

“…Research that investigated biomarkers to differentiate between heat stroke and COVID‐19 includes a report that compared the blood tests of 90 hospitalized heat stroke patients and 86 hospitalized COVID‐19 patients who were registered in the Heatstroke STUDY 2017–2019 that was conducted in Japan 36 . The results showed significant differences for the three items of white blood cells (10.8 × 10 3 /μL versus 5.2 × 10 3 /μL, P < 0.001), Cre (2.2 versus 0.85 mg/dL, P < 0.001), and CRP (0.2 versus 2.8 mg/dL, P < 0.001).…”

High incidence of heat illness and the potential burden on the health care system during the COVID-19 pandemic

“…Dysgeusia and dysosmia, although specific to COVID-19, do not appear in all patients. Second, no specific biomarkers exist to diagnose them; however, renal dysfunction or inflammatory reactions may be useful to differentiating them among selected populations (non-emergent mild to moderate cases) [4] . Third, although a history of close contact with COVID-19 patients supports its diagnosis, even without such a history, COVID-19 cannot be completely ruled out because pre-symptomatic patients can transmit the virus [5] .…”