Table 2.
Thyroid Function, Physical, and Mental Fatigability at Baseline and After 1 Year
| Variable | Baseline | At 1 year | ||||
|---|---|---|---|---|---|---|
| Levothyroxine (N = 119) | Placebo (N = 111) | Levothyroxine (N = 119) | Placebo (N = 111) | |||
| Thyrotropin—mIU/L | 6.08 ± 1.80 | 6.29 ± 2.01 | 3.08 ± 1.32 | 5.30 ± 2.34 | ||
| Median (IQR) | 5.56 (5.04 to 6.62) | 5.72 (5.06 to 6.76) | 2.95 (2.26 to 3.77) | 4.8 (3.62 to 6.57) | ||
| Primary Outcomes | Adjusted Between-Group Difference (95% CI) | p Value | ||||
| PFS physical score (SD)a | 14.7 ± 9.3 | 11.1 ± 9.1 | 14.8 ± 9.6 | 12.4 ± 9.3 | 0.2 (−1.8 to 2.1) | .88b |
| PFS mental score (SD)a | 7.4 ± 8.0 | 5.1 ± 6.9 | 6.0 ± 7.8 | 6.0 ± 8.0 | −1.0 (−2.8 to 0.8) | .26b |
| Secondary Outcomes | Adjusted Odds Ratio (95% CI) | p Value | ||||
| Participants with higher physical fatigability (%)c | 55 (46.2) | 33 (29.7) | 52 (43.7) | 41 (36.9) | 1.0 (0.5 to 1.8) | .88d |
| Participants with higher mental fatigability (%)c | 27 (22.7) | 14 (12.6) | 19 (16.0) | 20 (18.0) | 0.6 (0.3 to 1.4) | .23d |
aThe Pittsburgh Fatigability Scale (PFS) physical and mental subscores range from 0 to 50 with higher scores indicating greater fatigability. Crude means are reported.
b p-value generated through multiple linear regression model for the follow-up scores adjusted for PFS baseline scores, sex, country and starting levothyroxine dose.
cThe cut points for higher fatigability are set at ≥15 points for the physical PFS subscore and at ≥13 points for the mental PFS subscore (13,15), as previously established.
d p-value generated through multiple logistic regression model for the number of participants with higher fatigability at follow-up adjusted for number of participants with higher fatigability at baseline, sex, country and starting levothyroxine dose.