Clinical characteristics of low and high BMI Hidradenitis suppurativa patients
Riis PT, Saunte D, Marmol V, Benhadou F, Guillem P, El-Domyati M, Abdel-Wahab H, Antoniou C, Dessinioti C, Gurer MA, Beksac B, Szepietowski J, Mathusiak L, Emtestam L, Lapins J, Kottb HR, Doss N, Massa A, Hamzavi I, Nicholson C, Kim KH, Ohn J, Zouboulis C, Karagiannidis I, Durienc P, Bukvic ZM, Jemec G. Clinical characteristics of low and high BMI Hidradenitis suppurativa patients. Experimental Dermatology 2017; 26:14-15.
Obesity, as a risk factor is a common theme in Hidradenitis Suppurativa (HS) literature. HS patients as a group have higher Body Mass Index (BMI) than control population, high BMI patients suffer more severe disease, less frequently go into remission and respond less well to laser surgery and medical treatment. It is therefore of interest to study other phenotypical differences between HS patients with normal and very high BMI, to explore the hypothesis that BMI is a marker for other underlying differences.
Method: To examine this further we performed a survey and examination of 246 HS patients with a BMI under 25 and 205 patients with a BMI higher than 35. The survey include patients from 16 different centers.
Results: Univariable analysis showed several differences between low BMI and high BMI patients. Patients with a high BMI were older (median age 33 vs 38, P<0.001), had a higher age at first boil (median 20 vs 23, P=0.001), had a lower alcohol consumption (P=0.007) and were less prone to Acne (P=0.007). Patients with a high BMI were more severely affected by HS as assessed by Hurley staging, physician global assessment (PGA), and Patient reported severity score (Numeric rating scale 0–10) (P<0.001 for all). There was no difference in smoking status (P=0.783) or genetic disposition towards HS (P=0.088).
Logistic regression showed that an increase in 5 years in age of diagnosis was associated with an odds ratio of 0.72 and 0.67 for positive family history, for low and high BMI respectively (P>0.001). Indicating that patients with a positive family history have an earlier debut of symptoms.
Disease impact, as measured by patient reported severity (PRS) on a numeric rating scale from 0–10, was associated with increased BMI for the low BMI group with an increase of 0.37 PRS per BMI (P<0.001). For patients with a high BMI disease severity was not associated with BMI, but with Pack years, with an increase of 0.38 PRS per pack year (P=0.001).
Discussion: As previously reported, we find that positive family history is associated with earlier age of onset. Positive family history was however not associated with more severe disease. For high BMI patients positive family history was associated with more widespread disease, (P<0.001). For low BMI patients this association was not found (P=0.604). This suggests a synergistic relationship between BMI and genetics with regards to how wide‐spread lesions are Patients with high BMI experience greater impact from their HS and more severe disease.
Despite BMI being a risk factor for the development of the disease we did not find an overabundance of positive family history in the low BMI population. Interestingly disease impact if more closely linked to actual BMI in the low BMI group, whereas pack years seem the most prominent determinant for disease impact in the high BMI group. The results seemingly indicate that BMI primarily affects disease severity as distinct from onset of disease.