Cofactors and comorbidities of necrobiosis lipoidica: analysis of the German DRG data from 2012

Background: Necrobiosis lipoidica (NL) is a rare granulomatous inflammatory skin disease of unknown pathophysiology. Its potential association with diabetes mellitus is well known. Other relevant cofactors and comorbidities are subject to controversial debate. Patients and methods: DRG (diagnosis-related groups) data of all inpatients with a coded primary or secondary diagnosis of NL treated at German hospitals in 2012 were evaluated. Results: Data of 262 inpatient cases with the primary or secondary diagnosis of NL were analyzed. Women (63.4 %; n = 166) were nearly twice as frequently affected as men (36.2 %; n = 96). Most NL patients (14.8 %) were in the age group between 50 and 55 years. Among comorbidities included in the metabolic syndrome complex, diabetes mellitus was the most common (34.4 %; IDDM 20.6 %, NIDDM 13.8 %), while essential hypertension was observed in 9.2 %, obesity in 4.6 %, chronic heart failure in 4.1 %, and dyslipidemias in 2.3 % of cases. Leg ulcers were diagnosed in 7.3 % of individuals; other venous disorders, in 5.7 %. Conclusions: Our data analysis describes one of the largest compilations of patient cases with the diagnosis of NL worldwide. Besides the well-known association with diabetes mellitus, there are numerous other potentially relevant cofactors and comorbidities that should be considered in the diagnosis and management of NL patients.