Author, date and country | Patient group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
---|---|---|---|---|---|
Rui et al. April 2020 China | 119 confirmed COVID-19 and 45 healthy controls | Prospective observational | Progression to moderate, severe or critical disease | Urinary glucose and protein levels were associated with severity of disease, with more severe disease having significantly higher levels of glucose and protein. Urine tests can be used as a marker of kidney damage secondary to COVID. | Unbalanced number in case and control groups. Not necessarily a prognostic tool - authors suggest using as a confirmatory test. |
Dawei et al. February 2020 China | 138 hospitalised confirmed COVID patients in Wuhan | Retrospective observational | Admission to intensive care unit | Those admitted to ITU had - higher D-dimer, CK, creat, WCC, neutrophils, were older and had more co-morbidities. Only age was a statistically significant finding. | Authors admit to higher chance of type 1 error given style of analysis. Follow up ceased before discharge. |
Wei-jie et al. February 2020 China | 1099 confirmed COVID patients in mainland China | Retrospective observational | One or more of admission to ITU, mechanical ventilation, mortality | Severe cases (as defined by American Thoracic Society guidelines for community acquired pneumonia) were older, more likely to have co-morbidities, had more prominent laboratory abnormalities, and required ventilatory support. None of these findings were shown to be statistically significant. | Incomplete documentation of original case data. Selection bias for patients who present to hospital. Follow up ceased before discharge. |
Wang et al. March 2020 China | 60 confirmed COVID-19 patients, compared with normal subjects | Retrospective case-control study | Correlation of severe disease with biomarkers | Compared with healthy controls, COVID-19 positive patients had significantly lower total lymphocytes, CD4+ cells, CD8 + cells, B cells, and NK cells with higher CRP and ESR. There was some correlation with disease severity. | Lymphocyte subset not routinely collected. |
Henry et al. April 2020 USA | COVID-19 positive patients from China and Singapore | Meta-analysis of 24 articles | Correlation with severe disease and mortality with biomarkers. | Markedly increased white cell count (predominantly neutrophils), and reduced CD4+ and CD8+ T-cells, biomarkers of cardiac and muscle injury, LFTs, U+Es, coagulation tests, CRP, ferritin, IL-10 and IL-6 are indicative of severe disease and mortality. | No clear timing of blood tests. Variable definitions of severity across studies. Smaller sample size for mortality. |