A study led by researchers from the University of Kansas evaluated the impact of smoking on treatment outcomes for thyroid eye disease (TED) patients undergoing the novel therapy teprotumumab.
Give me some background.
Smoking is known to be the strongest modifiable risk factor consistently associated with the development and progression of TED as well as a decrease in treatment response.
When compared to non-smokers, patients with TED who smoke tend to respond poorly to treatments such as corticosteroids. However, the effect of smoking on the efficacy of teprotumumab is currently unknown.
Talk about the study.
In this single-center, retrospective cohort study, investigators enrolled 15 TED patients scheduled to start a treatment course of 8 infusions of teprotumumab.
Of these patients, 6 (40%) were current or former smokers and 9 were non-smokers; all patients with a history of smoking had type 2 disease, while all non-smokers had type 1 disease.
What were the findings?
Using the patients’ change in clinical activity score (CAS) to assess the primary outcome, the mean reduction in CAS was 3.2±2 in smokers and 4.9±2.2 in non-smokers.
There was no significant difference between smokers and non-smokers in baseline variables such as sex, thyroid stimulating hormone (TSH), free thyroxine (T4), free triiodothyronine (T3), and the number of infusions completed.
Additional variables included change in visual acuity (VA), proptosis, and diplopia. VA outcomes were not statistically significantly different between smokers and non-smokers.
Tell me more.
Investigators found a statistically significant reduction in proptosis between smokers and non-smokers. Proptosis was reduced by 1.2±1.2 in the right eye and by 1.75±0.5 in the left eye of smokers, whereas non-smokers decreased to 4±1.4 in the right eye and 4.2±1.8 in the left eye.
There was no statistically significant change in diplopia between the groups; however, it was more likely to be present prior to treatment in patients who smoke.
Of the 16 patients initially included in the study, 6 of 7 smokers (85.7%) had diplopia prior to treatment, compared to 6 of 9 non-smokers (66.6%).
Limitations?
This was a single-center study with a relatively small sample size, limiting the statistical power and generalizability of the data to larger populations. Additionally, patients were not stratified based on their status as current smokers or having a history of smoking.
Lastly, only a small percentage of patients in the study completed the full treatment course of teprotumumab.
Significance?
The authors stated that, for eyecare practitioners treating TED patients, providing “smoking cessation resources and counseling are vital … to prevent further disease progression and to prevent the development of TED in patients with thyroid dysfunction.”