Table 1.
Characteristics and Study Outcomes of Patients Divided into FT3 Tertiles
| Variable | FT3 tertiles |
P value | ||
|---|---|---|---|---|
| 2.4-4.0 pmol/L n =20 | 4.1-4.8 pmol/L n =17 | 4.9-7.4 pmol/L n = 17 | ||
| Age, mean (SD) | 68.75 (15.60) | 56.71 (14.88) | 48.98 (22.48) | .006 |
| Gender (%) | ||||
| Male | 15 (75.0) | 13 (76.5) | 9 (52.9) | .247 |
| Female | 5 (25.0) | 4 (23.5) | 8 (47.1) | … |
| BMI, mean (SD) | 26.49 (3.75) | 26.21 (4.56) | 26.66 (6.19) | .97 |
| Medical background | ||||
| DM (%) | 11 (55.0) | 4 (23.5) | 3 (17.6) | .033 |
| HTN (%) | 10 (50.0) | 8 (47.1) | 3 (17.6) | .093 |
| CVA (%) | 3 (15.0) | 3 (17.6) | 2 (11.8) | .89 |
| IHD (%) | 4 (20.0) | 1 (5.9) | 0 (0.0) | .095 |
| CHF (%) | 2 (10.0) | 1 (5.9) | 0 (0.0) | .416 |
| PVD (%) | 0 (0.0) | 1 (5.9) | 0 (0.0) | .33 |
| Autoimmune disease (%) | 1 (5.0) | 1 (5.9) | 0 (0.0) | .614 |
| Cognitive decline (%) | 4 (20.0) | 2 (11.8) | 4 (23.5) | .662 |
| Charlson index, mean (SD) | 5.00 (2.79) | 2.47 (1.87) | 1.65 (2.34) | <.001 |
| Smoking history (%) | 3 (15.0) | 3 (17.6) | 0 (0.0) | .205 |
| ED clinical parameters on presentation, mean (SD) | ||||
| Oxygen room air saturation (%) | 81.05 (17.92) | 92.71 (5.58) | 93.73 (7.03) | .006 |
| HR (bpm) | 94.75 (20.52) | 78.62 (15.60) | 101.30 (14.48) | .009 |
| RR (respiration/min) | 25.57 (9.06) | 22.62 (11.17) | 26.00 (12.17) | .61 |
| Temperature (°C) | 37.73 (0.73) | 37.73 (0.92) | 37.57 (0.67) | .858 |
| SBP (mm Hg) | 137.05 (21.41) | 135.79 (14.99) | 131.64 (22.48) | .767 |
| DBP (mm Hg) | 79.85 (10.45) | 76.86 (10.01) | 79.18 (10.78) | .704 |
| Laboratory results, mean (SD) | ||||
| Hb (g/dL) | 12.32 (2.30) | 13.88 (1.74) | 12.70 (2.54) | .18 |
| WBC (K/μL) | 11.04 (7.22) | 7.04 (2.76) | 7.98 (2.99) | .23 |
| PLT (K/μL) | 232.10 (89.12) | 228.35 (171.63) | 227.47 (77.68) | .55 |
| Neutrophils (K/μL) | 9.40 (7.32) | 5.21 (2.31) | 5.77 (2.47) | .17 |
| Lymphocytes (K/μL) | 0.78 (0.45) | 1.05 (0.59) | 1.36 (0.55) | .005 |
| Cr (mg/dL) | 1.30 (0.81) | 0.90 (0.33) | 0.67 (0.18) | .001 |
| Albumin (g/dL) | 3.23 (0.61) | 3.64 (0.65) | 3.79 (0.62) | .023 |
| ALT (IU/L) | 50.35 (44.79) | 32.71 (24.53) | 30.71 (14.12) | .13 |
| AST (IU/L) | 79.20 (71.52) | 49.06 (32.28) | 42.76 (19.70) | .22 |
| D-dimer (ng/mL) | 7556.88 (15450.71) | 2029.00 (2552.63) | 6697.64 (18253.27) | .09 |
| Ferritin (ng/mL) | 921.99 (773.91) | 647.61 (463.17) | 205.33 (267.29) | .002 |
| LDH (IU/L) | 492.89 (247.49) | 352.41 (154.12) | 289.88 (91.94) | .014 |
| Troponin-I HS (ng/L) | 109.79 (247.62) | 14.04 (15.17) | 39.10 (53.19) | .032 |
| CRP (mg/L) | 154.68 (90.48) | 80.70 (77.51) | 31.26 (60.73) | <.001 |
| Thyroid hormones, mean (SD) | ||||
| TSH (mIU/L)a | 2.51 (3.59) | 2.79 (3.25) | 3.12 (2.44) | .2 |
| FT4 (pmol/L)a | 13.78 (4.97) | 12.54 (3.35) | 13.21 (3.33) | .71 |
| FT3 (pmol/L)a | 3.40 (0.48) | 4.49 (0.23) | 5.56 (0.62) | <.001 |
| Min TSH (mIU/L) | 1.39 (1.88) | 1.60 (2.18) | 2.89 (2.47) | .039 |
| Min FT4 (pmol/L) | 9.24 (4.52) | 11.14 (2.22) | 12.68 (2.55) | .011 |
| Min FT3 (pmol/L) | 3.40 (0.48) | 4.49 (0.23) | 5.56 (0.62) | <.001 |
| Primary and secondary outcomes | ||||
| Death (n, %) | 8 (40.0) | 1 (5.9) | 1 (5.9) | .008 |
| Mechanical ventilation (n, %) | 9 (45.0) | 5 (29.4) | 0 (0.0) | .007 |
| ICU (n, %) | 11 (55.0) | 5 (29.4) | 1 (5.9) | .006 |
| LOS in days, mean (SD) | 40.06 (43.24) | 22.14 (23.55) | 13.98 (11.49) | .11 |
Abbreviations: ALT = alanine transaminase; AST = aspartate aminotransferase; BMI = body mass index; bpm = beats/min; CHF = congestive heart failure; Cr = creatinine; CRP = c-reactive protein; CVA = cerebrovascular accident; DBP = diastolic blood pressure; DM = diabetes mellitus; FT3 = free triiodothyronine; FT4 = free thyroxine; HR = heart rate; HTN= hypertension; Hb = hemoglobin; ICU = intensive care unit; IHD = ischemic heart disease; LDH = lactate dehydrogenase; LOS = length of stay; min = minimum; PLT = platelets; PVD = peripheral vascular disease; RR = respiratory rate; SBP = systolic blood pressure; TSH = thyroid stimulating hormone; WBC = white blood cell.
Normal reference ranges: TSH 0.4-4.0 mIU/L; FT4 7-16 pmol/L, FT3 3.3-7.2 pmol/L.