Treatment of hyperthyroidism with antithyroid drugs corrects mild neutropenia in Graves' disease.
BACKGROUND
Neutropenia secondary to antithyroid drug (ATD) therapy in Graves' disease (GD) is well recognized. However, the effect of hyperthyroidism, prior to and after ATD therapy, on neutrophil counts in patients with GD is unclear.


OBJECTIVE
To study the prevalence of neutropenia in newly diagnosed untreated GD and the effect of ATD on the neutrophil count.


METHODS
Prospective study from August 2010 to December 2014.


METHODS
Endocrinology outpatient clinic in a single centre.


METHODS
Consecutive patients (n = 206) with newly diagnosed GD.


METHODS
ATD therapy.


METHODS
Prevalence and factors predicting neutropenia (<2 × 109/l) and change in neutrophil counts following ATD.


RESULTS
At diagnosis, 29 (14·1%) of GD individuals had neutropenia. Non-Caucasians [odds ratio (95% CI) of 4·06 (1·14-14·45), P = 0·03] and patients with higher serum thyroid hormone levels [OR 1·07 (1·02-1·13), P = 0·002 for serum FT3] were the only independent predictors of neutropenia. All patients with neutropenia had normalized blood neutrophil levels after achieving euthyroidism with ATD therapy. In patients in whom data were available posteuthyroidism (n = 149), change in neutrophil count after achieving euthyroidism was independently related to reduction in thyroid hormone levels (P < 0·01).


CONCLUSIONS
GD is associated with neutropenia in one in seven patients at diagnosis, especially in non-Caucasians and those with higher serum thyroid hormone levels. Neutrophil counts increase with treatment with ATD and are related to reduction in thyroid hormone concentrations. It is therefore important to check neutrophil levels in newly diagnosed patients with GD prior to commencing ATD therapy as otherwise low levels may incorrectly be attributed to ATD therapy.
Department of Endocrinology, University Hospital of North Tees, Stockton-on-Tees, UK.
N
N
Aggarwal
Department of Endocrinology, Gateshead Health NHS Foundation Trust, Gateshead, UK.
S A
SA
Tee
Department of Endocrinology, Gateshead Health NHS Foundation Trust, Gateshead, UK.
W
W
Saqib
Department of Endocrinology, Gateshead Health NHS Foundation Trust, Gateshead, UK.
T
T
Fretwell
Department of Haematology, Gateshead Health NHS Foundation NHS Trust, Gateshead, UK.
G P
GP
Summerfield
Department of Endocrinology, Gateshead Health NHS Foundation Trust, Gateshead, UK.|Institute of Genetic Medicine, Newcastle University, Gateshead, UK.
S
S
Razvi
D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use; D002452:Cell Count; D005260:Female; D006111:Graves Disease / Q000150:complications*; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009503:Neutropenia / Q000517:prevention & control*; D009504:Neutrophils; D011446:Prospective Studies; D013963:Thyroid Hormones / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D013956:Antithyroid Agents; D013963:Thyroid Hormones; D014284:Triiodothyronine