Ankylosing Spondylitis Not Linked to Increased Risk of Alopecia

New data from a nationwide population-based cohort study suggest patients with ankylosing spondylitis (AS) do not have an increased risk of alopecia compared to patients without AS.

Although alopecia and AS share a common feature of male predominance, alopecia did not seem to occur more frequently in patients with AS in these findings or in a subgroup analysis of androgenetic alopecia.

“These data could reduce concerns of AS patients as well as dispel the doubt among healthcare providers when taking care of patients with AS,” wrote study author James Cheng-Chung Wei, Division of Allergy, Immunology and Rheumatology, Chung Shan Medical University Hospital.

In order to provide education and recommendations about skincare, investigators noted it is crucial to clarify the association between hair loss and underlying AS. However, a lack of data from an adequate sample size makes the answer controversial.

As such, the current nationwide study was designed to evaluate the risk of alopecia in patients with AS. The study extracted data from over 1 million people in the Taiwan Longitudinal Health Insurance Database.

They selected newly diagnosed patients with AS from 2000 - 2012 and included only those with ≥3 outpatient department visits or admission at least once. The index date was set as the date of the patient’s first AS diagnosis.

The non-AS comparison group included patients who had never been diagnosed with AS from 1999 - 2013 to include all appropriate patients for the control group during the entire tracking period of the study, investigators noted.

They considered the primary outcome alopecia diagnosis with the first sub-outcome being androgenetic alopecia. Using Cox proportional hazard models, the adjusted hazard ratio (HR) was adjusted for age, sex, hypertension, hyperlipidemia, diabetes, atopic dermitis, and mental disorder.

A total of 3640 patients with AS and 14,560 non-AS controls were selected. The risk of alopecia was assessed in all patients, wherein the adjusted HR showed no statistical significance (adjusted HR, 1.16; 95% CI, 0.67 - 1.98; P = .599).

A subgroup analysis was performed to clarify age and sex differences in the association between alopecia and AS, with the results showing no statistical significance:

• Age 20 - 40 years: HR, 1.03; 95% CI, 0.53 - 2.01; P = .925
• Age ≥40 years: HR, 1.49; 95% CI, 0.58 - 3.80; P = .406
• Female: HR, 1.17; 95% CI, 0.43 - 3.17; P = .759
• Male: HR, 1.15; 95% CI, 0.61 - 2.19, P = .667

Moreover, different phenotypes of alopecia including androgenetic alopecia and alopecia areata were further classified under subgroup analysis. Both were found to be statistically insignificant (androgenetic alopecia: HR 1.19, 95% CI 0.58-2.41 and alopecia areata: HR 0.98, 95% CI 0.37-2.62).

The data additionally show patients with atopic dermatitis were found to be associated with a higher risk of alopecia (adjusted HR, 8.05; 95% CI, 1.11 - 58.14; P = .039). Other comorbidities did not seem to have a significant correlation with alopecia.

The study, “No increased risk of alopecia in ankylosing spondylitis patients: A population-based cohort study in Taiwan,” was published in the International Journal of Rheumatic Diseases.