Glucocorticoids are preferable to thionamides as first-line treatment for amiodarone-induced thyrotoxicosis due to destructive thyroiditis: a matched retrospective cohort study.
BACKGROUND
Type 2 amiodarone-induced thyrotoxicosis (AIT) is a destructive thyroiditis usually responsive to glucocorticoids; however, recent surveys showed that many expert thyroidologists worldwide use thionamides for type 2 AIT patients.


OBJECTIVE
The objective of the study was to compare the effectiveness of methimazole (MMI) or prednisone (GLU) in type 2 AIT patients who had a short cure time according to a published predictive model.


METHODS
This was a matched retrospective cohort study.


METHODS
The study was conducted at a university center.


METHODS
Forty-two untreated type 2 AIT patients with a predicted cure time < or = 40 d were divided into two groups (MMI and GLU groups). After matching for the predicted cure time, patients in the GLU group were selected in a 1:1 ratio to patients in the MMI group.


METHODS
Patients were treated with GLU or MMI for 40 d. Patients still thyrotoxic after 40 d continued glucocorticoids if in the GLU group or were switched to prednisone (MMI-GLU group) if in the MMI group.


METHODS
Time and rate of cure (healing) at 40 d were measured.


RESULTS
Patients still thyrotoxic after 40 d were 23.8 +/- 9.3% in the GLU group and 85.7 +/- 7.6% in the MMI group (P = 0.000). The GLU and MMI-GLU groups did not significantly differ in the nonhealing rate at 40 d (P = 0.730). When patients in the MMI group were treated with glucocorticoids, 94.1% patients achieved euthyroidism within 40 d. However, the global median cure time (MMI period + prednisone period) was longer (60 d, 95% confidence interval 53.5-66.5 d) in the MMI-GLU group than the GLU group (21 d, 95% confidence interval 15.1-26.9 d).


CONCLUSIONS
Glucocorticoids are the first-line treatment in type 2 AIT, whereas thionamides play no role in this destructive thyroiditis.
Bogazzi
Fausto
F
Department of Endocrinology and Metabolism, University of Pisa, 56124 Pisa, Italy. f.bogazzi@endoc.med.unipi.it
Tomisti
Luca
L
Rossi
Giuseppe
G
Dell'Unto
Enrica
E
Pepe
Pasquale
P
Bartalena
Luigi
L
Martino
Enio
E
D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000008:administration & dosage / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects*; D013956:Antithyroid Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008713:Methimazole / Q000627:therapeutic use*; D008875:Middle Aged; D011241:Prednisone / Q000627:therapeutic use*; D012189:Retrospective Studies; D013966:Thyroiditis / Q000139:chemically induced / Q000188:drug therapy*; D013971:Thyrotoxicosis / Q000139:chemically induced / Q000188:drug therapy*
D000889:Anti-Arrhythmia Agents; D013956:Antithyroid Agents; D005938:Glucocorticoids; D008713:Methimazole; D000638:Amiodarone; D011241:Prednisone