High neutrophil-to-lymphocyte ratio is associated with relapse in Graves' disease after antithyroid drug therapy.

Antithyroid drugs (ATDs) are effective in controlling hyperthyroidism due to Graves' disease (GD); however, long-term remission rates are low. The neutrophil-to-lymphocyte ratio (NLR) is a useful prognostic marker in many inflammatory diseases. We aimed to evaluate whether NLR can be used as a prognostic marker for relapse in patients with GD after ATD therapy. This retrospective cohort study included 108 patients with newly diagnosed GD who achieved remission after ATD therapy and were followed-up for >12 months after ATD discontinuation. The primary outcome was relapse-free survival (RFS). Patients were classified into two groups according to baseline NLR: low NLR group with NLR < 1.14 (n = 59; 55%) and high NLR group with NLR ≥ 1.14 (n = 49; 45%). During the median follow-up of 6.5 years, disease relapse after a year of ATD withdrawal occurred in 23 (21%) patients. The patients with high NLR had poorer RFS than those with low NLR, and RFS curves were significantly different between the two groups (p = 0.002). In multivariate analysis, a high NLR (OR = 4.22, p = 0.016) was an independent prognostic factor for relapse in patients with GD after adjusting for age, sex, goiter, orbitopathy, thyroid hormone levels, thyrotropin binding inhibiting immunoglobulin titer, and the duration of ATD therapy. This study showed that NLR can be an early and cost-effective prognostic biomarker for relapse in patients with GD after ATD therapy. Further studies are needed to validate the prognostic role of NLR in GD.