Epidemiological study of lupus in children in the UK and Ireland;

An epidemiological study of juvenile-onset systemic lupus erythematosus (JSLE) or childhood lupus using British Paediatric Surveillance Unit (BPSU) methodology has been completed. JSLE is a rare disease where the immune system attacks many parts of the body. There has not previously been a study that looks at all patients presenting with JSLE throughout the UK and Ireland so the incidence (number of new cases per year) is not well-defined. This study aimed to understand how many children and young people in the UK and Ireland develop JSLE each year, as well as looking at how they present, how well classification criteria work and what treatments are used. We hope that understanding this will help us to better look after children and young people with JSLE.

Doctors looking after patients with a new diagnosis of JSLE over a two year period (from September 2017) filled in a pseudo-anonymised questionnaire with clinical information at diagnosis and one year later using BPSU methodology. Patients recruited to the UK JSLE cohort study but not reported via the BPSU were also included in incidence analyses. Approval for the study was gained from the Research Ethics Committee and Confidentiality Advisory Group.

There were 124 patients included in the final analysis with an additional 7 patients identified through the UK JLSE cohort study included in the incidence analysis. The incidence was found to be 0.36 – 0.46/100,000 children aged <16 years of age, with the highest incidence when all cases with a clinician diagnosis of JSLE were included and lower incidence when including patients meeting classification criteria (0.36/100,000 when including patients meeting American College of Rheumatology classification criteria (ACR-1997), 0.41/100,000 when including patients meeting systemic lupus international collaborating clinics classification criteria (SLICC-2012).

There were 112 patients reported via the BPSU who met sufficient criteria to be defined as lupus using at least one classification system (ACR-1997 or SLICC-2012) who were included in more detailed analysis. The median (average) time to diagnosis from symptom onset was 4 months but it varied, with some patients experiencing very significant delay (diagnosis took over 12 months from symptom onset for 22% of patients). Patients had an average of five different body systems involved at diagnosis and a lot of patients had fatigue (83%). Over a fifth (20%) had damage caused by their disease when measured using a formal damage index called the SLICC damage index in the year following diagnosis. Most patients (98%) received systemic immunomodulating treatment. Systemic steroids were used to treat most patients with over two-thirds (71%) remaining on systemic steroids one year after diagnosis.

This study defines the minimum incidence of JSLE to be 0.36 – 0.46 / 100,000 children aged <16 years of age depending on the case definition used.  It also highlights the high disease and treatment burden for JSLE patients. These data highlight how important research to develop steroid-sparing treatments and appropriately use of immunomodulatory treatment is. Work is already underway in the UK for a treat to target approach to treating JSLE.