Risk of venous thrombosis for different FT4 levels (adjusted for sex and age)
| FT4* . | Percentile† . | Controls (n = 379) . | VT (n = 190)‡ . | DVT (n = 155) . | Unprovoked VT (n = 69)‡ . | Unprovoked DVT (n = 51) . | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| n . | OR (95% CI) . | n . | OR (95% CI) . | n . | OR (95% CI) . | n . | OR (95% CI) . | |||
| Less than 10 pmol/L | LoRef | 2 | 0 | NA | 0 | NA | 0 | NA | 0 | NA |
| Less than 11 pmol/L | 1 | 3 | 0 | NA | 0 | NA | 0 | NA | 0 | NA |
| Less than 12 pmol/L | 5 | 16 | 1 | 0.1 (0.0-0.9) | 1 | 0.2 (0.0-1.2) | 1 | 0.4 (0.0-2.7) | 1 | 0.5 (0.1-4.0) |
| Less than 13 pmol/L | 10 | 36 | 9 | 0.5 (0.2-1.0) | 6 | 0.4 (0.2-1.0) | 5 | 0.8 (0.3-2.2) | 2 | 0.4 (0.1-1.9) |
| Less than 14 pmol/L | 30 | 85 | 36 | 0.8 (0.5-1.3) | 28 | 0.8 (0.5-1.3) | 14 | 1.0 (0.5-1.8) | 8 | 0.8 (0.3-1.7) |
| Greater than 16 pmol/L | 60 | 121 | 76 | 1.4 (1.0-2.0) | 69 | 1.7 (1.1-2.4) | 25 | 1.2 (0.7-2.0) | 23 | 1.6 (0.9-3.0) |
| Greater than 17 pmol/L | 80 | 68 | 46 | 1.4 (0.9-2.2) | 41 | 1.6 (1.0-2.5) | 18 | 1.5 (0.8-2.7) | 18 | 2.2 (1.2-4.2) |
| Greater than 18 pmol/L | 90 | 35 | 28 | 1.7 (1.0-2.9) | 27 | 2.0 (1.1-3.4) | 13 | 2.0 (1.0-4.1) | 13 | 2.8 (1.4-6.0) |
| Greater than 19 pmol/L | 95 | 12 | 16 | 2.8 (1.3-6.1) | 15 | 3.1 (1.4-6.9) | 9 | 3.9 (1.6-9.9) | 9 | 5.4 (2.1-13.8) |
| Greater than 20 pmol/L | 97.5 | 6 | 9 | 3.1 (1.1-8.8) | 9 | 3.7 (1.3-10.6) | 5 | 4.2 (1.2-14.5) | 5 | 5.8 (1.7-20.3) |
| Greater than 22 pmol/L | 99 | 3 | 7 | 4.7 (1.2-18.6) | 7 | 5.7 (1.5-22.5) | 5 | 8.9 (2.0-38.5) | 5 | 12.5 (2.8-55.4) |
| Greater than 24 pmol/L | UpRef | 1 | 3 | 5.9 (0.6-57.3) | 3 | 6.9 (0.7-67.7) | 2 | 9.6 (0.8-109.1) | 2 | 13.0 (1.1-154.1) |
| FT4* . | Percentile† . | Controls (n = 379) . | VT (n = 190)‡ . | DVT (n = 155) . | Unprovoked VT (n = 69)‡ . | Unprovoked DVT (n = 51) . | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| n . | OR (95% CI) . | n . | OR (95% CI) . | n . | OR (95% CI) . | n . | OR (95% CI) . | |||
| Less than 10 pmol/L | LoRef | 2 | 0 | NA | 0 | NA | 0 | NA | 0 | NA |
| Less than 11 pmol/L | 1 | 3 | 0 | NA | 0 | NA | 0 | NA | 0 | NA |
| Less than 12 pmol/L | 5 | 16 | 1 | 0.1 (0.0-0.9) | 1 | 0.2 (0.0-1.2) | 1 | 0.4 (0.0-2.7) | 1 | 0.5 (0.1-4.0) |
| Less than 13 pmol/L | 10 | 36 | 9 | 0.5 (0.2-1.0) | 6 | 0.4 (0.2-1.0) | 5 | 0.8 (0.3-2.2) | 2 | 0.4 (0.1-1.9) |
| Less than 14 pmol/L | 30 | 85 | 36 | 0.8 (0.5-1.3) | 28 | 0.8 (0.5-1.3) | 14 | 1.0 (0.5-1.8) | 8 | 0.8 (0.3-1.7) |
| Greater than 16 pmol/L | 60 | 121 | 76 | 1.4 (1.0-2.0) | 69 | 1.7 (1.1-2.4) | 25 | 1.2 (0.7-2.0) | 23 | 1.6 (0.9-3.0) |
| Greater than 17 pmol/L | 80 | 68 | 46 | 1.4 (0.9-2.2) | 41 | 1.6 (1.0-2.5) | 18 | 1.5 (0.8-2.7) | 18 | 2.2 (1.2-4.2) |
| Greater than 18 pmol/L | 90 | 35 | 28 | 1.7 (1.0-2.9) | 27 | 2.0 (1.1-3.4) | 13 | 2.0 (1.0-4.1) | 13 | 2.8 (1.4-6.0) |
| Greater than 19 pmol/L | 95 | 12 | 16 | 2.8 (1.3-6.1) | 15 | 3.1 (1.4-6.9) | 9 | 3.9 (1.6-9.9) | 9 | 5.4 (2.1-13.8) |
| Greater than 20 pmol/L | 97.5 | 6 | 9 | 3.1 (1.1-8.8) | 9 | 3.7 (1.3-10.6) | 5 | 4.2 (1.2-14.5) | 5 | 5.8 (1.7-20.3) |
| Greater than 22 pmol/L | 99 | 3 | 7 | 4.7 (1.2-18.6) | 7 | 5.7 (1.5-22.5) | 5 | 8.9 (2.0-38.5) | 5 | 12.5 (2.8-55.4) |
| Greater than 24 pmol/L | UpRef | 1 | 3 | 5.9 (0.6-57.3) | 3 | 6.9 (0.7-67.7) | 2 | 9.6 (0.8-109.1) | 2 | 13.0 (1.1-154.1) |
FT4 indicates free thyroxine; VT indicates venous thrombosis; DVT, deep venous thrombosis; OR, odds ratio; CI, confidence interval; LoRef, lower limit of reference range; NA, not applicable; and UpRef, upper limit of reference range.
Reference range is 10-24 pmol/L.
Analysis was performed for the 1st, 2.5th, 5th, 10th, 20th, 30th, 40th, 50th, 60th, 70th, 80th, 90th, 95th, 97.5th, and 99th percentiles, as well as for FT4 levels below or above reference range. Because of laboratory reportage of FT4 results in round figures, the 1st percentile corresponded with the 2.5th percentile, the 10th percentile with the 20th percentile, the 50th percentile with the 60th percentile, and the 70th percentile with the 80th percentile. For each cutoff level below the 50th percentile, we compared subjects below the cutoff to subjects above this level, thus setting the latter as reference; vice versa for each cutoff level above the 50th percentile.
DVT, calf vein thrombosis, or thrombophlebitis.