Table 4. Subgroup Analyses for Patients on Daily Levothyroxine Dose of More Than 100 μg and 100 μg or Less .
| Patients, No. (%) | Risk or mean difference (95% CI) | P value | ||
|---|---|---|---|---|
| Nonswitchers | Switchers | |||
| Levothyroxine dose >100 μg (n = 364) | ||||
| TSH level | ||||
| Normal (0.3-4.4 mIU/L) | 258 (70.9) | 279 (76.6) | Risk difference: −0.058 (−0.122 to 0.006) | .08 |
| Abnormal (<0.3 or >4.4 mIU/L) | 106 (29.1) | 85 (23.4) | Risk difference: 0.058 (−0.006 to 0.122) | .08 |
| Markedly abnormal (<0.1 or >10 mIU/L) | 32 (8.8) | 27 (7.4) | Risk difference: 0.014 (−0.026 to 0.053) | .50 |
| Mean TSH level, (SD), mIU/L | 2.53 (3.09) | 2.53 (6.40) | Mean difference: 0 (−0.73 to 0.74) | 1.00 |
| Mean TSH level change from baseline, (SD), mIU/L | 0.84 (3.10) | 0.93 (6.30) | Mean difference: −0.09 (−0.82 to 0.63) | .80 |
| Levothyroxine dose ≤100 μg (n = 2409) | ||||
| TSH level | ||||
| Normal (0.3-4.4 mIU/L) | 2034 (84.4) | 2062 (85.6) | Risk difference: −0.012 (−0.032 to 0.009) | .26 |
| Abnormal (<0.3 or >4.4 mIU/L) | 375 (15.6) | 347 (14.4) | Risk difference: 0.012 (−0.009 to 0.032) | .26 |
| Markedly abnormal (<0.1 or >10 mIU/L) | 50 (2.1) | 42 (1.7) | Risk difference: 0.003 (−0.004 to 0.011) | .40 |
| Mean TSH level, (SD), mIU/L | 2.83 (2.61) | 2.76 (2.51) | Mean difference: 0.07 (−0.08 to 0.21) | .37 |
| Mean TSH level change from baseline, (SD), mIU/L | 0.55 (2.53) | 0.47 (2.48) | Mean difference: 0.08 (−0.06 to 0.22) | .26 |
Abbreviation: TSH, thyrotropin.