Risk of vitiligo in patients with SARS-CoV-2 vaccination or infection: a nationwide cohort study.

As recent sporadic case reports of newly developed vitiligo after SARS-CoV-2 infection or vaccination have been -published, a convincing large-scale study addressing this association is warranted. To investigate the association between SARS-CoV-2 infection or vaccination and vitiligo using the Korean National Health Insurance Service database. SARS-CoV-2-positive patients and those vaccinated against SARS-CoV-2 were recruited. In studies 1 and 2, control groups were selected based on 1:1 propensity score matching with vaccinated and SARS-CoV-2-positive patients, respectively. The occurrence of vitiligo was the main outcome. Each individual was monitored for six months. The hazard ratio (HR) for vitiligo was calculated using the Cox proportional hazards model. In study 1, the incidence of vitiligo in the vaccination group was 2.22-fold higher than that in the non-vaccination group (adjusted HR [aHR]: 2.22; 95% confidence interval [CI]: 1.54-3.19). Rheumatoid arthritis was a risk factor for vitiligo (aHR: 1.99; 95% CI: 1.12-3.54). Conversely, two factors associated with decreased incidence of vitiligo were male sex (aHR: 0.58; 95% CI: 0.40-0.82) and rural residency (aHR: 0.68; 95% CI: 0.49-0.96). In study 2, the incidence of newly-diagnosed vitiligo was not significantly different between SARS-CoV-2-positive patients and uninfected controls (aHR: 0.95; 95% CI: 0.51-1.78). SARS-CoV-2 vaccination may increase the risk of developing vitiligo in South Korea, although additional studies in other countries or with extended periods are needed. Clinicians should be aware of the impact of SARS-CoV-2 infection and vaccination on autoimmune skin diseases, including vitiligo.

Incidence and risk factors of breast cancer-related lymphedema in Korea: a nationwide retrospective cohort study.

BACKGROUND: Breast cancer-related lymphedema (BCRL) is a secondary lymphedema that occurs after breast cancer related treatments. BCRL develops from damage or dysfunction of the normally functioning lymphatic system due to surgery, radiation therapy, and rarely due to cancer recurrence. This nationwide, retrospective study was aimed at investigating the incidence and risk factors of BCRL using the database of the Korean National Health Insurance Service (NHIS). METHODS: Patients with newly diagnosed breast cancer who underwent breast surgery from 1 January 2017 to 31 December 2020, were recruited. The incidence was compared by four groups according to the operation type of breast cancer [breast conserving surgery (BCS) with sentinel lymph node biopsy (S), BCS with axillary lymph node dissection (A), total mastectomy (TM) with S, modified radical mastectomy (MRM)]. The incidence rates of lymphedema were calculated by the number of incident events by the total follow-up period. Cox proportional hazard regression was used to calculate the risk of incidence of lymphedema based on a patients' characteristics, breast cancer treatment, and comorbidities. RESULTS: The final cohort of operation subjects that satisfied the inclusion criteria was 34 676. BCRL occurred in 4242 patients (12.2%), and the median follow-up period was 695.4 days. The BCRL was diagnosed in the BCS with S (8.0%), BCS with A (23.5%), TM with S (10.7%), and MRM (28.5%) with an incidence of 40.8, 132.2, 55.8, and 171.8 per 1000 person-years, respectively. Young age, obesity, chemotherapy, radiotherapy, residence in metropolitan areas, and hyperlipidemia were identified as risk factors. CONCLUSION: In Korea, the incidence of BCRL was found to be 12.2%, with the highest risk observed among patients who underwent MRM. Therefore, surgical oncologists should meticulously assess the appropriate surgical approach and consider providing education to patients with risk factors for BCRL, aiming to ensure effective prevention strategies.

Risk of Alopecia Areata After COVID-19.

This cohort study examines the incidence, prevalence, and risk of alopecia areata after COVID-19.