Table 2.
Multivariable-adjusted RR and 95% CI for adverse outcomes in COVID-19 patients.
| Levels of serum iron metabolism indices |
P-trend | Per SD increment | |||
|---|---|---|---|---|---|
| Tertile 1 | Tertile 2 | Tertile 3 | |||
| Serum iron, μmol/L | <10.7 | 10.7–15.8 | ≥15.8 | ||
| Severe | 1 | 0.42 (0.22, 0.84) | 0.44 (0.22, 0.87) | 0.01 | 0.71 (0.53, 0.94) |
| ARDS | 1 | 0.52 (0.28, 0.98) | 0.48 (0.25, 0.92) | 0.02 | 0.72 (0.55, 0.95) |
| Coagulopathy | 1 | 0.30 (0.11, 0.81) | 0.27 (0.10, 0.76) | 0.01 | 0.53 (0.34, 0.80) |
| ACI | 1 | 0.45 (0.21, 0.96) | 0.24 (0.09, 0.63) | 0.002 | 0.55 (0.39, 0.79) |
| ALI | 1 | 0.84 (0.38, 1.83) | 0.75 (0.35, 1.59) | 0.45 | 0.91 (0.67, 1.24) |
| AKI | 1 | 0.53 (0.18, 1.54) | 0.16 (0.04, 0.63) | 0.008 | 0.55 (0.34, 0.89) |
| Serum ferritin, ng/mL | <269.7 | 269.7–561.6 | ≥561.6 | ||
| Severe | 1 | 2.28 (0.93, 5.57) | 4.02 (1.67, 9.69) | 0.001 | 1.37 (1.16, 1.63) |
| ARDS | 1 | 1.86 (0.83, 4.21) | 3.13 (1.40, 6.98) | 0.004 | 1.34 (1.14, 1.59) |
| Coagulopathy | 1 | 2.84 (0.58, 13.77) | 5.86 (1.27, 26.97) | 0.01 | 1.21 (0.92, 1.58) |
| ACI | 1 | 2.34 (0.84, 6.51) | 2.91 (1.03, 8.27) | 0.07 | 1.36 (1.11, 1.66) |
| ALI | 1 | 1.33 (0.46, 3.83) | 3.61 (1.43, 9.09) | 0.002 | 1.33 (1.09, 1.63) |
| AKI | 1 | 1.20 (0.28, 5.10) | 1.73 (0.39, 7.66) | 0.41 | 1.02 (0.61, 1.69) |
| Serum transferrin, g/L | <1.6 | 1.6–2.0 | ≥2.0 | ||
| Severe | 1 | 0.50 (0.28, 0.91) | 0.21 (0.08, 0.52) | 0.0002 | 0.52 (0.38, 0.70) |
| ARDS | 1 | 0.56 (0.32, 1.00) | 0.24 (0.10, 0.56) | 0.0004 | 0.55 (0.41, 0.74) |
| Coagulopathy | 1 | 0.41 (0.17, 0.96) | 0.19 (0.04, 0.85) | 0.005 | 0.39 (0.25, 0.63) |
| ACI | 1 | 0.35 (0.16, 0.75) | 0.40 (0.16, 1.02) | 0.007 | 0.49 (0.34, 0.72) |
| ALI | 1 | 0.70 (0.33, 1.45) | 0.49 (0.20, 1.17) | 0.09 | 0.69 (0.49, 0.96) |
| AKI | 1 | 0.21 (0.06, 0.72) | 0.33 (0.08, 1.32) | 0.02 | 0.54 (0.32, 0.92) |
| Soluble transferrin receptor, ng/mL | <2.5 | 2.5–3.2 | ≥3.2 | ||
| Severe | 1 | 0.65 (0.34, 1.25) | 0.72 (0.38, 1.35) | 0.32 | 0.87 (0.63, 1.21) |
| ARDS | 1 | 0.69 (0.37, 1.29) | 0.70 (0.37, 1.30) | 0.26 | 0.86 (0.62, 1.18) |
| Coagulopathy | 1 | 0.41 (0.16, 1.10) | 0.51 (0.21, 1.23) | 0.12 | 0.69 (0.38, 1.23) |
| ACI | 1 | 0.61 (0.27, 1.40) | 0.96 (0.46, 1.98) | 0.98 | 1.10 (0.81, 1.49) |
| ALI | 1 | 0.79 (0.37, 1.71) | 0.78 (0.36, 1.66) | 0.52 | 0.77 (0.52, 1.16) |
| AKI | 1 | 1.17 (0.35, 3.88) | 1.56 (0.50, 4.85) | 0.42 | 1.17 (0.80, 1.72) |
| Transferrin saturation, % | <28.0 | 28.0–39.8 | ≥39.8 | ||
| Severe | 1 | 0.71 (0.37, 1.36) | 0.61 (0.30, 1.22) | 0.16 | 0.93 (0.72, 1.21) |
| ARDS | 1 | 0.86 (0.47, 1.59) | 0.59 (0.30, 1.17) | 0.13 | 0.92 (0.72, 1.19) |
| Coagulopathy | 1 | 0.57 (0.23, 1.42) | 0.35 (0.13, 0.96) | 0.04 | 0.76 (0.52, 1.11) |
| ACI | 1 | 0.81 (0.39, 1.70) | 0.60 (0.26, 1.41) | 0.24 | 0.80 (0.59, 1.09) |
| ALI | 1 | 0.78 (0.34, 1.78) | 1.01 (0.48, 2.17) | 0.91 | 1.03 (0.75, 1.41) |
| AKI | 1 | 0.65 (0.20, 2.13) | 0.33 (0.10, 1.12) | 0.07 | 0.70 (0.45, 1.10) |
| Total iron-binding capacity, μmol/L | <35.6 | 35.6–44.4 | ≥44.4 | ||
| Severe | 1 | 0.50 (0.27, 0.90) | 0.27 (0.11, 0.64) | 0.0007 | 0.55 (0.40, 0.74) |
| ARDS | 1 | 0.56 (0.31, 0.99) | 0.30 (0.13, 0.68) | 0.002 | 0.58 (0.43, 0.77) |
| Coagulopathy | 1 | 0.39 (0.17, 0.93) | 0.19 (0.04, 0.89) | 0.005 | 0.40 (0.25, 0.64) |
| ACI | 1 | 0.40 (0.19, 0.83) | 0.27 (0.09, 0.81) | 0.003 | 0.51 (0.35, 0.74) |
| ALI | 1 | 0.86 (0.42, 1.77) | 0.45 (0.19, 1.12) | 0.10 | 0.71 (0.51, 0.99) |
| AKI | 1 | 0.38 (0.13, 1.16) | 0.22 (0.04, 1.08) | 0.02 | 0.53 (0.32, 0.90) |
| Unsaturated iron-binding capacity, μmol/L | <21.3 | 21.3–29.2 | ≥29.2 | ||
| Severe | 1 | 0.56 (0.29, 1.07) | 0.50 (0.24, 1.02) | 0.04 | 0.72 (0.53, 0.97) |
| ARDS | 1 | 0.62 (0.33, 1.16) | 0.54 (0.27, 1.09) | 0.06 | 0.75 (0.56, 1.00) |
| Coagulopathy | 1 | 0.47 (0.19, 1.17) | 0.46 (0.16, 1.35) | 0.08 | 0.71 (0.46, 1.09) |
| ACI | 1 | 0.46 (0.21, 1.04) | 0.68 (0.31, 1.50) | 0.20 | 0.82 (0.59, 1.15) |
| ALI | 1 | 0.64 (0.31, 1.35) | 0.50 (0.20, 1.21) | 0.10 | 0.73 (0.50, 1.06) |
| AKI | 1 | 0.74 (0.28, 1.98) | 0.76 (0.21, 2.74) | 0.57 | 0.87 (0.52, 1.45) |
Multivariable Poisson regression model was adjusted for age, sex, IL-6, and pre-existing comorbidities (including hypertension, diabetes, cardiac disease, cerebrovascular disease, chronic pulmonary disease, chronic kidney disease, chronic liver disease, and tumor).
Linear trend test was conducted using the median value of each category of every iron metabolism parameter.
Abbreviations: ACI = acute liver injury; AKI = acute kidney injury; ALI = acute liver injury; ARDS = acute respiratory distress syndrome; COVID-19 = coronary disease 2019; RR = relative risk.