Abstract
Multiple visits are needed to achieve euthyroidism on levothyroxine in newly
detected primary hypothyroidism. We aimed to develop a levothyroxine dose
estimation algorithm for primary hypothyroidism. Adults with newly diagnosed
hypothyroidism were enrolled prospectively, first in the training cohort,
followed by the validation cohort separated by time and person. We developed
a predictive algorithm from Training Cohort and validated the model in
Validation Cohort. Training Cohort: In this cohort, 358 subjects (259 women
and 99 men) were enrolled. The median duration needed to achieve
euthyroidism was 4±0.5 months. The mean levothyroxine daily dose was
60.5±34.1 μg. Data of euthyroid subjects within 6
months of treatment initiation and age range 18–65 years were used
for algorithm development. In the multivariable linear regression algorithm,
pretreatment serum thyrotropin level, and sex formed the best-fit predictive
model (adjusted R2 0.73, p-value <0.001). Validation
Cohort: Eighty-four subjects (61 women and 23 men) were enrolled and started
on an estimated levothyroxine dose derived from the developed prediction
model. On the first follow-up on treatment, 34/50 participants
achieved euthyroidism (68%) at 1.5 months. In conclusion, the
proposed prediction model for levothyroxine dose estimation effectively
achieves early euthyroidism in two-third subjects in the age range of
18–65 years.
Key words
levothyroxine - hypothyroidism - thyroid stimulating hormone
