Acute Respiratory Distress Syndrome, COVID-19, Severe Respiratory Distress Syndrome
Conditions
Keywords
Soluble urokinase plasminogen activator receptor, suPAR, Respiratory failure, Mechanical ventilation, Biomarker, Real world data, Observational Cohort study
Brief summary
This is a retrospective, non interventional cohort study using stored plasma samples from appoximately 300 adults hospitalized with confirmed COVID 19. Baseline suPAR measured using the suPARnostic TurbiLatex assay on the Roche cobas c501.
Detailed description
The Michigan Medicine COVID-19 Cohort (M2C2) is the largest sub-cohort of the International Study on Inflammation in COVID-19 (ISIC). The M2C2 comprises consecutive, systematically enrolled adults (≥18 years) with confirmed SARS-CoV-2 infection hospitalized specifically for COVID-19 at the University of Michigan from 1 February 2020 to 1 June 2021. Adult patients hospitalized in participating U.S. hospitals with confirmed COVID 19 infection during the study period, who had baseline suPAR measured using the suPARnostic TurbiLatex assay on Roche cobas c501 on plasma samples obtained within 48 hours of admission. The cohort reflects real world U.S. data and includes racially and ethnically diverse populations with typical U.S. burdens of obesity, diabetes, and chronic kidney disease. SAMPLE SIZE JUSTIFICATION - Since we have a fixed 6 ng/mL threshold and are only validating (not discovering), the analysis is just a 2×2 table. True sensitivity 94% (matching SPARCOL): N=136 is enough True sensitivity 90% (conservative): N=237 is enough True sensitivity 88% (worst case): N=440 needed SPARCOL showed 93.9%, so N=300 covers you even if U.S. sensitivity drops to \ 88% - a generous safety margin. STATED LIMITATIONS * N=300 does not support fully adjusted multivariable logistic regression * Hispanic and Asian subgroups are too small for standalone powered analyses. These subgroups are reported descriptively. * Formal non-inferiority testing of sensitivity (U.S. vs. SPARCOL) would require a larger sample. The comparison is performed descriptively, with the acceptance criterion applied to the U.S. data independently (lower 95% CI \> 80%). CONCLUSION We have previously considered measuring 1200 samples, but a balance between statistical rigor and practical feasibility (assay cost, data extraction effort) we recalculated number needed to N=300 which according to the power calculation is an appropriate sample size for this validation study. REFERENCES 1. Hayek SS, Vasb inder A, Engoren M, et al. J Med Virol. 2024; 96(1):e29389. PMID: 38235904. 2. Chalkias A, Skoulakis A, Papagiannakis N, et al. Eur J Clin Invest. 022;52(7):e13794. PMID: 35435245. 3. Altintas I, Eugen-Olsen J, Seppala S, et al. Biomark Insights. 2021;16. PMID: 34421295. 4. Peduzzi P, Concato J, Kemper E, et al. J Clin Epidemiol. 1996; 49(12):1373-1379. 5. FDA Q-Sub Q240207/A001 Meeting Minutes, April 15, 2024. 6. Hanley JA, McNeil BJ. Radiology. 1982;143(1):29-36.
Interventions
DIAGNOSTIC_TESTsuPARnostic® TurbiLatex Assay on Roche cobas c501
Quantitative measurement of soluble urokinase plasminogen activator receptor (suPAR) in human EDTA plasma using the suPARnostic TurbiLatex particle enhanced turbidimetric immunoassay performed on the Roche Diagnostics cobas c501 analyzer. Results are reported in ng/mL and interpreted using a pre specified clinical threshold of 6 ng/mL to identify patients at increased risk for progression to severe respiratory failure.
Sponsors
ViroGates A/S
University of Michigan
The University of Texas Medical Branch, Galveston
Study design
Observational model
COHORT
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Inclusion Criteria 1. Age ≥18 years at hospital admission. 2. Confirmed SARS CoV 2 infection documented in the EHR (positive RT PCR or antigen test from a respiratory specimen). 3. suPAR level measured from EDTA plasma using the suPARnostic TurbiLatex assay on a Roche cobas c501 analyzer on samples taken within 24 hours of Emergency Department presentation or hospital admission. 4. Available 30 day follow up data from the date of admission (30 day vital status and SRF status ascertainable). *
Exclusion criteria
1. Already intubated and/or receiving invasive mechanical ventilation at the time of suPAR sample collection. 2. Documented "Do Not Intubate" order or determination that the patient was not a candidate for mechanical ventilation at admission. 3. suPAR measured by a method other than the suPARnostic TurbiLatex assay on Roche cobas c501 (e.g., ELISA, other platforms). 4. Incomplete primary endpoint data (SRF status cannot be determined within 30 days). 5. Patients with confirmed SARS CoV 2 infection who were not primarily admitted for COVID 19 (incidental positive test in a non COVID admission).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Severe respiratory failure (SRF) within 30 days | Statistical analysis will be carried out in March 2026 | Development of severe respiratory failure requiring endotracheal intubation and initiation of invasive mechanical ventilation within 30 days of hospital admission. SRF is ascertained from EHR procedure codes and clinical documentation. Performance metrics (sensitivity, specificity, PPV, NPV, AUC) at the suPAR ≥6 ng/mL threshold will be calculated. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Secondary outcomes (optional) | March 2026 | Compare performance to European SPARCOL cohort |
| Subgroup analysis | March 2026 | Evaluate performance across subgroups (sex, age, race/ethnicity, BMI, diabetes, CKD, SARS-CoV-2 variant era). |
| Composite endpoint | March 2026 | Evaluate suPAR ≥6 ng/mL for ICU admission, 30-day mortality, and composite (SRF or death). |
Countries
United States
Outcome results
None listed