Table 2.
Associations between serial biomarkers over time and survival in mechanically ventilated patients with COVID-19
| Log(hs-cTnT) |
Log(CK) |
Log(CK-MB) |
Log(NT-proBNP) |
|||||
|---|---|---|---|---|---|---|---|---|
| Model | Regression Coefficient(95% CI) | p Value | Regression Coefficient (95% CI) | p Value | Regression Coefficient (95% CI) | p Value | Regression Coefficient (95% CI) | p Value |
| Model 1 | ||||||||
| ICU-nonsurvivor (reference) | ref | ref | ref | ref | ref | ref | ref | ref |
| ICU-survivor* | −0.93 (−1.37; −0.49) | <0.001 | −0.20 (−0.57; 0.17) | 0.289 | −0.41 (−0.70; −0.13) | 0.005 | −0.39 (−0.96; 0.19) | 0.182 |
| Interaction between group and time† | 0.01 (−0.01; 0.03) | 0.348 | 0.03 (0.01; 0.06) | 0.059 | 0.02 (0.00; 0.03) | 0.049 | −0.08 (−0.11; −0.04) | <0.001 |
| Model 2 | ||||||||
| ICU-nonsurvivor (reference) | ref | ref | ref | ref | ref | ref | ref | ref |
| ICU-survivor* | −0.74 (−1.17; −0.30) | 0.001 | −0.18 (−0.55; 0.20) | 0.360 | −0.29 (−0.57; 0.00) | 0.048 | −0.32 (−0.90; 0.26) | 0.279 |
| Interaction between group and time† | 0.01 (−0.01; 0.03) | 0.449 | 0.04 (0.01; 0.06) | 0.003 | 0.02 (0.00; 0.03) | 0.059 | −0.08 (−0.11; −0.05) | <0.001 |
| Model 3 | ||||||||
| ICU-nonsurvivor (reference) | ref | ref | ref | ref | ref | ref | ref | ref |
| ICU-survivor* | −0.66 (−1.08; −0.24) | 0.003 | −0.14 (−0.52; 0.24) | 0.460 | −0.25 (−0.52; 0.03) | 0.084 | −0.28 (−0.85; 0.29) | 0.331 |
| Interaction between group and time† | 0.01 (−0.02; 0.03) | 0.560 | 0.03 (0.01; 0.06) | 0.005 | 0.01 (0.00; 0.03) | 0.088 | −0.08 (−0.11; −0.05) | <0.001 |
| Model 4 | ||||||||
| ICU-nonsurvivor (reference) | ref | ref | ref | ref | ref | ref | ref | ref |
| ICU-survivor* | −0.47 (−0.95; 0.00) | 0.049 | −0.03 (−0.41; 0.35) | 0.871 | −0.13 (−0.40; 0.14) | 0.342 | −0.10 (−0.62; 0.43) | 0.717 |
| Interaction between group and time† | 0.01 (−0.02; 0.03) | 0.588 | 0.01 (0.03; 0.05) | 0.014 | 0.02 (0.00; 0.03) | 0.179 | −0.08 (−0.12; −0.05) | <0.001 |
| Model 5 | ||||||||
| ICU-nonsurvivor (reference) | ref | ref | ref | ref | ref | ref | ref | ref |
| ICU-survivor* | −0.55 (−1.04; −0.07) | 0.028 | −0.09 (−0.47; 0.29) | 0.634 | −0.15 (−0.42; 0.12) | 0.284 | −0.13 (−0.67; 0.40) | 0.631 |
| Interaction between group and time† | 0.01 (−0.02; 0.03) | 0.511 | 0.03 (0.01; 0.06) | 0.008 | 0.02 (0.00; 0.03) | 0.161 | −0.08 (−0.12; −0.05) | <0.001 |
Biomarker data were log-transformed for reasons of normality and skewed residuals.
Results of the linear mixed-effects models show the difference in log-biomarker development over time between ICU survivors and ICU nonsurvivors, with ICU nonsurvivors as the reference category. Data are regression coefficients (β) with 95% confidence intervals (CIs). The regression coefficient β indicates the mean difference in log biomarker over time. The regression β for the between-group and time interaction indicates the changes in log biomarker over time between ICU survivors and ICU nonsurvivors (with ICU nonsurvivors as reference: ref). Model 1 is the crude model; model 2 adjusts for gender and age; model 3 additionally adjusts for APACHE-II score at baseline; model 4 also adjusts for daily creatinine concentration; model 5 also adjusts for smoking status, the presence of hypertension, diabetes, and obesity.
APACHE = Acute Physiology and Chronic Health Evaluation; CI = confidence interval; ICU = intensive care unit.
A negative regression coefficient indicates that the average log-biomarker concentration of survivors at day 1 is lower compared with the nonsurvivors.
A negative regression coefficient for the interaction term indicates that the log-biomarker concentration of survivors decreases more over time compared with the nonsurvivors. (i.e., the interaction between group and time models the change over time for both groups separately).