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Original Investigation
May 20, 2020

Disease Trajectories for Hidradenitis Suppurativa in the Danish Population

Author Affiliations
  • 1Department of Dermatology, Zealand University Hospital, Roskilde, Denmark
  • 2Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
JAMA Dermatol. Published online May 20, 2020. doi:10.1001/jamadermatol.2020.1281
Key Points

Question  What are the temporal associations of comorbidities with hidradenitis suppurativa diagnosis?

Findings  In this cohort study of 14 488 patients with hidradenitis suppurativa from Denmark, inflammatory diseases, diabetes, depression, asthma, and reaction to severe stress, and adjustment disorders frequently preceded the diagnosis of hidradenitis suppurativa and may be associated with its development.

Meaning  The findings suggest that patients with newly diagnosed hidradenitis suppurativa may have a high frequency of type 1 diabetes and subsequent high risk of acute myocardial infarction, pneumonia, and chronic obstructive pulmonary disease.


Importance  Hidradenitis suppurativa (HS) is a chronic skin disease characterized by recurrent inflamed nodular lesions and is associated with multiple comorbidities; previous studies have been of cross-sectional design, and the temporal association of HS with multiple comorbidities remains undetermined.

Objective  To evaluate and characterize disease trajectories in patients with HS using population-wide disease registry data.

Design, Setting, and Participants  This retrospective registry-based cohort study included the entire Danish population alive between January 1, 1994, and April 10, 2018 (7 191 519 unique individuals). Among these, 14 488 Danish inhabitants were diagnosed with HS or fulfilled diagnostic criteria identified through surgical procedure codes.

Exposures  Citizens of Denmark with a diagnosis code of HS as defined by International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) or as identified through surgical procedures.

Main Outcomes and Measures  Disease trajectories experienced more frequently by patients with HS than by the overall Danish population. Strength of associations between disease co-occurrences was evaluated using relative risk (RR). All significant disease pairs were tested for directionality using a binomial test, and pairs with directionality were merged into disease trajectories of 3 consecutive diseases. Numerous disease trajectories were combined into a disease progression network showing the most frequent disease paths over time for patients with HS.

Results  A total of 11 929 individuals were identified by ICD-10 diagnosis codes (8392 [70.3%] female; mean [SD] age, 37.72 [13.01] years), and 2791 were identified by procedural codes (1686 [60.4%] female; mean [SD] age, 37.38 [15.83]). The set of most common temporal disease trajectories included 25 diagnoses and had a characteristic appearance in which genitourinary, respiratory, or mental and behavioral disorders preceded the diagnosis of HS and chronic obstructive pulmonary disease (604 cases [4.2%]; RR, 1.57; 95% CI, 1.55-1.59; P < .001), pneumonia (827 [5.7%]; RR, 1.18; 95% CI, 1.15-1.20; P < .001), and acute myocardial infarction (293 [2.0%]; RR, 1.37; 95% CI, 1.35-1.39; P < .001) developed after the diagnosis.

Conclusions and Relevance  The findings suggest that patients with newly diagnosed HS may have a high frequency of manifest type 1 diabetes and subsequent high risk of acute myocardial infarction, pneumonia, and chronic obstructive pulmonary disease.

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