Table 1.
Baseline characteristics.
| Prior to randomization (n = 59) | Allocated to first LT4 then LT3 (n = 27) | Allocated to first LT3 then LT4 (n = 32) | P value | |
|---|---|---|---|---|
| Age at inclusion (years) | 42.9 ± 9.7 | 42.8 ± 8.6 | 42.9 ± 10.7 | 0.991 |
| Age at hypothyroidism diagnosis (years) | 30.6 ± 10.2 | 29.8 ± 8.6 | 31.2 ± 11.4 | 0.590 |
| Duration of substitution monotherapy LT4 (years) | 10.6 ± 7.0 | 10.9 ± 7.3 | 10.3 ± 6.8 | 0.778 |
| Type of therapy at inclusion | ||||
| LT4 monotherapy | 46 (78.0) | 20 (74.1) | 26 (81.3) | 0.513 |
| LT4/LT3 combination therapy | 12 (20.3) | 7 (25.9) | 5 (15.5) | 0.728 |
| Thyroid extract | 1 (1.7) | 0 (0) | 1 (3.1) | 1.000 |
| Etiology of hypothyroidism | ||||
| Autoimmune/idiopathic | 56 (94.9) | 27 (100%) | 29 (90.6) | 0.299 |
| Post-surgical | 2 (3.4) | 0 (0) | 2 (6.3) | 0.549 |
| Radioiodine | 1 (1.7) | 0 (0) | 1 (3.1) | 1.000 |
| Body mass index (kg/m2) | 28.1 ± 5.6 | 28.5 ± 5.9 | 27.8 ± 5.5 | 0.624 |
| Resting heart rate (beats/minute) | 64.7 ± 11.2 | 67.4 ± 12.1 | 62.4 ± 9.9 | 0.084 |
| Systolic blood pressure (mmHg) | 118.0 ± 13.7 | 115.5 ± 13.2 | 120.2 ± 13.9 | 0.191 |
| Diastolic blood pressure (mmHg) | 78.3 ± 7.9 | 77.2 ± 8.7 | 79.4 ± 7.0 | 0.282 |
| TSH (mU/L) | 0.64 (0.26-1.60) | 0.82 (0.28-1.50) | 0.63 (0.25-1.9) | 0.767 |
| FT4 (pmol/L) | 16.8 (14.7-19.0) | 17.0 (14.2-20.0) | 16.4 (14.8-18.0) | 0.970 |
| FT3 (pmol/L) | 4.4 (3.8-4.9) | 4.4 (3.8-4.8) | 4.4 (3.8-5.0) | 0.664 |
| Positive TPO-ab1 | 31 (52.5) | 17 (63.0) | 14 (43.8) | 0.226 |
| Residual hypothyroid symptoms | ||||
| Fatigue | 57 (96.6) | 26 (96.3) | 31 (96.6) | 1.000 |
| Cold-intolerance | 54 (91,5) | 26 (96.3) | 28 (87.5) | 0.460 |
| Cognitive disturbances | 48 (81.4) | 24 (88.9) | 24 (75.0) | 0.303 |
| Emotional disturbances | 38 (64.4) | 16 (59.3) | 22 (68.8) | 0.627 |
Data are presented as mean ± SD or number (%) or median (interquartile range: 25-75%) as appropriate.
TSH, thyroid stimulating hormone; FT4, free thyroxine; FT3, free triiodothyronine; TPO-ab, thyroid peroxidase antibodies. 1Cut-off value for positive TPO-ab was 35 kIU/l.