Background Previous studies have shown that smoking is closely related to the occurrence, severity and response to orbital radiation in Graves’ ophthalmopathy (GO). The aim of this study was to investigate whether smoking impacts the response to intravenous 4.5 g methylprednisolone therapy in patients with active moderate-to-severe GO.

Methods Ninety-two individuals with active moderate-to-severe GO who were treated with cumulative doses of 4.5 g intravenous methylprednisolone within 3 months were recruited. The patients were grouped as never smokers, active smokers (including smokers and quit smokers) and passive smokers.

Results We observed significantly greater response rate in never smokers compared with active smokers (73.9% vs 29.0%, p=0.001). After adjusting the confounding factors such as age, sex, body mass index, clinical activity score, thyroid-stimulating hormone receptor antibody and the duration of GO, smoking was independently associated with poor intravenous glucocorticoid (GC) response (OR 12.40, 95% CI 1.20 to 128.14, p=0.035). We also found the response rate was significantly higher in never smokers than in quit smokers (73.9% vs 16.7%, p=0.001), while no statistical significance between current smokers and quit smokers (36.8% vs 16.7%, p=0.228). There was a trend of poor response for passive smokers compared with never smokers (64.7% vs 72.2%, p=0.583).

Conclusions Smoking, even past smoking, was an independent risk factor associated with impaired response to intravenous corticosteroids in patients with GO. Smokers with GO should be given optimised treatment strategy such as higher dose of GC or combined radiation therapy.