Alopecia Areata: No Clear Increased Risk of Venous Thromboembolism

Study that Included Approximately 18,000 Patients with Alopecia Areata Did not Identify Increased Risk of Blood Clots

A new study from Harvard Medical School and affiliated institutions found that patients with alopecia areata had similar risks for developing blood clots as people do in the general population.

The authors performed a cohort study using commercial insurance claims data from a nationwide US health care database. Data from 2004, through 2019 were analyzed. A variety of skin conditions were evaluated but here we will focus on alopecia areata. For example, a total of 158 123 patients with psoriasis, atopic dermatitis, alopecia areata, vitiligo, or hidradenitis suppurativa were included in the study.

There were 17,889 patients with alopecia areata inlcuded in this study.

Alopecia Areata Not Associated with An Increased Risk of Blood Clots

The incidence rate (per 1000 person-years) of outpatient or inpatient VTE was 0.94 in alopecia areata compared with 1.76 in patients without a chronic inflammatory skin disease. After propensity-score matching to patients without a CISD, the hazard ratio (HR) of VTE was 0.97 (95% CI, 0.65-1.46) in alopecia areata. Given that the confidence interval overlaps zero, this indicates that patients with alopecia areata do not appear to have either a decreased risk of blood clots or an increased risk of blood clots.

Conclusion

This is important information for clinicians and researchers. There is still some debate in the medical literature as to whether some of the drugs we use to treat alopecia (such as JAK inhibitors) come with an increased risk of blood clots (venous thromboembolism). It’s important to understand the baseline risk in our patient populations. It appears that alopecia areata is not likely to be associated with an increased risk of blood clots.

REFERENCES

Schneeweiss MC et al. Incidence of Venous Thromboembolism in Patients With Dermatologist-Diagnosed Chronic Inflammatory Skin Diseases. JAMA Dermatol. 2021 Jul 1;157(7):805-816.