Prevalence, incidence and treatment patterns of prurigo nodularis in England: a retrospective database analysis

Abstract

Abstract Background Prurigo nodularis (PN) is a pruritic skin disease characterized by multiple intensely itchy skin nodules in symmetrically distributed areas of the extremities. There are limited studies on the epidemiology and treatment pathways of PN, especially moderate-to-severe PN, from England. Objectives To assess the epidemiology and treatment pathways of mild and moderate-to-severe PN in England. Methods This retrospective cohort study used data from the Clinical Practice Research Datalink and Hospital Episode Statistics in England. Adult patients (aged ≥ 18 years) with a PN-specific diagnosis code allocated any time between 1 April 2007 and 1 March 2019 (patient identification period) were selected. Patients were included if their first PN diagnostic code (index diagnosis date; IDD) was recorded during the identification period, with data available 6 months before and ≥ 12 months after the IDD. Patients were classified as having moderate-to-severe PN (MSPN) or mild PN (MiPN), based on the presence or absence of a prescription record, post-IDD, for either a systemic immunosuppressant or a gabapentinoid. Patients with MSPN and MiPN were matched 1 : 1 according to age, sex and IDD. Prevalence and incidence were calculated for each year from 2007 to 2019. Drugs prescribed post-IDD were analysed. Results A total of 8933 patients (MSPN, n = 2498; MiPN, n = 6435) were included in the study; 2462 patients with MiPN and 2462 with MSPN were included for the comparative analysis. The presence of atopic dermatitis, asthma and eosinophilic oesophagitis were significantly higher (all P < 0.001) in patients with MSPN compared with those with MiPN. The overall prevalence of cases of PN increased during the study period. The incidence rate also showed a similar trend. The rates of prescription of potent and super-potent topical corticosteroids (TCS), topical calcineurin inhibitors, first- and second-generation antihistamines, oral and injectable systemic corticosteroids, methotrexate, antidepressants and tacrolimus were significantly higher (all P < 0.001) in patients with MSPN compared with those with MiPN. Conclusions The epidemiology of PN was consistent with that found in other European studies. Patients with MSPN received a significantly higher number of prescriptions for potent TCS and systemic drugs compared with patients with MiPN.