Table 1.
Clinical Parameters and Thyroid Function Test Results at Baseline and End of Study by Intention to Treat
| Variable | Baseline | End of Study |
P Value | ||
|---|---|---|---|---|---|
| Arm 1 (Low-Normal TSH) | Arm 2 (High-Normal TSH) | Arm 3 (Mildly Elevated TSH) | |||
| Subjects, n | 138 | 46 | 47 | 45 | |
| Age, y | 49.2 ± 1 | 49.5 ± 1.7 | 50.9 ± 1.8 | 49.3 ± 1.6 | 0.77 |
| Sexa | |||||
| Female | 91% | 41 (89.1) | 41 (87.2) | 43 (95.6) | 0.45 |
| Male | 9% | 5 (10.9) | 6 (12.8) | 2 (4.4) | |
| Estrogen statusa | |||||
| Male | 9% | 5 (10.9) | 6 (12.8) | 2 (4.4) | 0.50 |
| Prenone | 39% | 19 (41.3) | 15 (31.9) | 20 (44.4) | |
| Preon | 9% | 4 (8.7) | 5 (10.6) | 4 (8.9) | |
| Postnone | 38% | 18 (39.1) | 19 (40.4) | 15 (33.3) | |
| Poston | 4% | 0 (0) | 2 (4.3) | 4 (8.9) | |
| Ethnicitya | |||||
| White | 92% | 44 (95.7) | 41 (87.2) | 42 (93.3) | 0.35 |
| Other | 8% | 2 (4.3) | 6 (12.8) | 3 (6.7) | |
| Body mass index, kg/m2 | 27.8 ± 0.5 | 28.6 ± 0.8 | 27.3 ± 0.8 | 27.6 ± 1.0 | 0.58 |
| LT4 duration,a y | 11.9 ± 0.8 | 9.9 ± 1.3 | 15.9 ± 1.7 | 9.7 ± 0.9 | < 0.001b,c |
| Current LT4 dose duration,a y | 1.63 ± 0.19 | 1.75 ± 0.35 | 1.50 ± 0.18 | 1.63 ± 0.40 | 0.86 |
| LT4 dose, µg/kg | 1.44 ± 0.04 | 1.50 ± 0.07 | 1.32 ± 0.07 | 0.78 ± 0.08 | < 0.001c,d |
| LT4 dose change,e µg/kg | NA | 0.14 ± 0.02 | −0.21 ± 0.03 | −0.64 ± 0.05 | < 0.001b,c,d |
| TSH, mU/L | 2.21 ± 0.13 | 1.85 ± 0.25 | 3.93 ± 0.38 | 9.49 ± 0.80 | < 0.001b,c,d |
| TSH change,e mU/L | −0.18 ± 0.33 | 1.60 ± 0.42 | 7.23 ± 0.86 | < 0.001c,d | |
| fT4, ng/dL | 1.67 ± 0.03 | 1.79 ± 0.06 | 1.64 ± 0.07 | 1.34 ± 0.05 | < 0.001c,d |
| fT4 change,e ng/dL | 0.13 ± 0.07 | −0.04 ± 0.07 | −0.32 ± 0.06 | < 0.001c,d | |
| fT3, pg/dL | 214 ± 4.2 | 201.4 ± 6.0 | 191.1 ± 6.2 | 184.1 ± 6.6 | 0.15 |
| f T3 change,e pg/dL | −18.9 ± 9.3 | −14.4 ± 6.9 | −32.4 ± 7.9 | 0.27 | |
Data presented as n, mean ± SEM, or n (%); differences between arms were tested using analysis of variance, and follow-up post hoc Tukey multiple comparisons were used to determine which arms had statistically significant differences at the 5% level.
Abbreviations: Postnone, postmenopausal, no hormonal treatment; Poston, postmenopausal with hormonal treatment; Prenone, premenopausal, no hormonal treatment; Preon, premenopausal with hormonal treatment.
a
Values at baseline for each arm.
b
Arm 1 vs arm 2.
c
Arm 2 vs arm 3.
d
Arm 1 vs arm 3.
e
Change variables provided as differences between end of study and baseline, stratified by treatment arm.