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 (years) | 42.9 | 42.8 ± 8.6 | 42.9 ± 10.7 | 0.99 |
| Age at hypothyroidism diagnosis (years) | 30.6 ± 10.2 | 29.8 ± 8.6 | 31.2 ± 11.4 | 0.59 |
| Duration of substitution monotherapy LT4 (years) | 10.6 ± 7.0 | 10.9 ± 7.3 | 10.3 ± 6.8 | 0.78 |
| Type of therapy at inclusion | ||||
| LT4 monotherapy | 46 (78.0) | 20 (74.1) | 26 (81.3) | 0.51 |
| LT4/LT3 combination therapy | 12 (20.3) | 7 (25.9) | 5 (15.5) | 0.73 |
| Thyroid extract | 1 (1.7) | 0 (0) | 1 (3.1) | 1.00 |
| Etiology of hypothyroidism | ||||
| Autoimmune/ idiopathic |
56 (94.9) | 27 (100%) | 29 (90.6) | 0.30 |
| Post-surgical | 2 (3.4) | 0 (0) | 2 (6.3) | 0.55 |
| Radioiodine | 1 (1.7) | 0 (0) | 1 (3.1) | 1.00 |
| Body mass index (kg/m2) | 28.1 ± 5.6 | 28.5 ± 5.9 | 27.8 ± 5.5 | 0.62 |
| TSH (mU/L) | 0.64 (0.26-1.60) | 0.82 (0.28-1.50) | 0.63 (0.25-1.9) | 0.77 |
| FT4 (pmol/L) | 16.8 (14.7-19.0) | 17.0 (14.2-20.0) | 16.4 (14.8-18.0) | 0.97 |
| FT3 (pmol/L) | 4.4 (3.8-4.9) | 4.4 (3.8-4.8) | 4.4 (3.8-5.0) | 0.66 |
| Positive TPO-ab1 | 31 (52.5) | 17 (63.0) | 14 (43.8) | 0.23 |
| Any residual hypothyroid symptoms | ||||
| Fatigue | 57 (96.6) | 26 (96.3) | 31 (96.6) | 1.00 |
| Cold-intolerance | 54 (91,5) | 26 (96.3) | 28 (87.5) | 0.46 |
| Cognitive disturbances | 48 (81.4) | 24 (88.9) | 24 (75.0) | 0.30 |
| Emotional disturbances | 38 (64.4) | 16 (59.3) | 22 (68.8) | 0.63 |
Data are presented as mean ± SD or number (%) or median (interquartile range: 25-75%) as appropriate.
*P values for analysis of differences between the two treatment groups.
TSH, thyroid stimulating hormone (normal range 0.5-3.6); FT4, free thyroxine (8.0-21.0); FT3, free triiodothyronine (2.8-7.0); TPO-ab, thyroid peroxidase antibodies. 1Cut-off value for positive TPO-ab was 35 kIU/l.