This paper is useful in indicating how long it takes to recover TSH levels after start of treatment for hypothyroidism, and that a considerable proportion of patients were, according to TSH normalisation or not, were incorrectly treated. Of course, we know TSH normalisation on T4 only isn't a good measure of treatment adequacy, but nevertheless it does show a) TSH rise delay and b) based on this, signs of incorrect treatment. It does however, show the intellectual contortions that such studies make to try to reconcile the irreconcilable.
Excli Journal
21:104-116
DOI: 10.17179/excli2021-4291
Julie Lindgård Nielsen, Jesper Karmisholt, Inge Bülow Pedersen, Allan Carlé
Suboptimal Thyroid Hormone Replacement Is Associated With Worse Hospital Outcomes
Abstract
The aim of this study is to evaluate the adequacy of treatment, and to identify factors influencing treatment of hypothyroidism. Patients newly diagnosed with overt hypothyroidism (n=345) were identified via a register linked to a laboratory database. In selected periods with staff available, 165 patients were invited, and 113 (68.5 %) accepted participating in a comprehensive program including blood tests and completion of questionnaires. We performed a longitudinal follow-up on thyroid function tests 10 years after the diagnosis. Time to reach a serum TSH level of 0.2-10 mU/L (termed as clinically acceptable) and biochemical normalization (TSH: 0.2-5.0 mU/L), respectively, were analyzed using Kaplan Meier survival analysis. Predictors for longer duration to reach the normal TSH range were identified using cox proportional hazards regression. Only 67.7 % of the patients were in the euthyroid range on the long term after diagnosis of overt hypothyroidism (2 years: 59.4 %; 10 years: 67.7 %). Median time to the first normal TSH was 8.9 months (95 % CI: 7.6-10.2 months). The factors associated with longer duration until normalization of TSH after multivariate analysis were age (HR 0.79 per 10 years; 95 % CI: 0.66-0.94; P = <0.01), smoking (HR 0.47; 95 % CI: 0.26-0.83; P = <0.01), serum TSH at diagnosis (HR 0.96 per 10 mU/L; 95 % CI: 0.93-0.99; P = 0.02) and BMI (HR 0.96 per kg/m2; 95 % CI: 0.91-0.99; P = 0.03). A considerable number of hypothyroid patients remained inadequately treated. When treating hypothyroid patients, special attention should be addressed to those patients who never or lately obtain euthyroid status.