Table 3.
Median (IQR) serum concentrations of T4, T3, fT4, and TSH in 917 cats with hyperthyroidism separated into 2 groups based on history of prior treatment with methimazole
| Cat Group | Serum T4 (μg/dL) | Serum T3 (ng/dL) | Serum fT4 (pmol/L) | Serum TSH (ng/mL) |
|---|---|---|---|---|
| No methimazole (494) | 7.3 (5.2–11.2) | 137 (100–215) | 99 (73–100) | 0.02 (0.02) |
| Mild (121) | 4.4 (3.9–4.8) | 94 (69–117) | 67 (56–76) | 0.02 (0.02) |
| Mild‐moderate (117) | 6.1 (5.6–6.4) | 114 (97–135) | 85 (68–100) | 0.02 (0.02) |
| Moderate (94) | 7.9 (7.4–9.0) | 152 (120–189) | 100 (86–100) | 0.02 (0.02) |
| Moderate‐severe (104) | 11.6 (10.9–12.8) | 219 (182–269) | 100 (100–100) | 0.02 (0.02) |
| Severe (58) | 19.8 (17.2–21.0) | 340 (272–419) | 100 (100–100) | 0.02 (0.02) |
| Methimazole (423) | 9.7 (6.4–16.6)a | 172 (113–310)a | 100 (84–100)a | 0.02 (0.02) |
| Mild (63) | 4.5 (3.7–4.8) | 87 (75–112) | 67 (59–76) | 0.02 (0.02) |
| Mild‐moderate (66) | 6.2 (5.6–6.7) | 112 (88–135) | 86 (72–100) | 0.02 (0.02) |
| Moderate (89) | 8.0 (7.6–9.0) | 155 (126–178) | 100 (87–100) | 0.02 (0.02) |
| Moderate‐severe (79) | 11.5 (10.6–12.7) | 203 (156–259) | 100 (100–100) | 0.02 (0.02) |
| Severe (126) | 20.8 (18.2–23.0)b | 406 (309–513)b | 100 (100–100) | 0.02 (0.02) |
a
Median concentration of entire treated group significantly higher (P < .001) than concentration in entire untreated group.
b
Median concentration of treated group significantly higher (P < .05) than concentration of same disease severity category in untreated group.