Objectives
In recent years, Hidradenitis suppurativa has received increased attention but still lack well-defined, robust patient-reported outcome measures. Such measures are likely to be influenced by contextual factors. We, therefore, aim to describe the association of biological and other factors with HS patient's self-evaluated health as reflected by the EQ5D VAS score.

Methods
This cross-sectional study measured basic information, Dermatology Life Quality Index, Major Depression Inventory and Euro-QoL-5D. Information obtained through questionnaires was used to create a model showing the relation between biological factors, questionnaire results and self-evaluated health using the stepwise method for linear regression. Patients with HS (n = 805) registered at our department were invited to participate. A total of 503 (62.5%) patients replied to this survey. There was no difference in basic demographics between responders and non-responders.

Results
Possible predictors for this study were DLQI, MDI, BMI, smoking, gender. A final model for correlation with self-evaluated health was obtained. Significant predictors for the model were DLQI (P < 0.05), BMI points above 25 and active smoking (both: P < 0.01) and MDI (P < 0.001).

Conclusion
As this is a cross-sectional study, it reveals several clinically relevant correlations. Smoking appears to correlate with the highest change in VAS score, but an MDI of 10 (lower than study average) or a BMI of 40 influences the results more. This study provides an assessment of how much BMI and smoking, in relation to other factors, correlate to the self-evaluated health state of patients with HS. These may, therefore, be relevant contextual factors to the construction and interpretation of specific patient-reported outcome measures. To improve QoL, we advocate smoking cessation and weight loss, and advice active screening for depression as over 10% of our patients qualify for a depressive diagnosis according to ICD-10.