Real-world data in lupus nephritis: results from a European survey on renal function testing and burden of disease progression.

Objective: Patients with lupus nephritis (LN), a severe renal manifestation of systemic lupus erythematosus, should be monitored for progression of chronic kidney disease to end-stage renal disease but data on renal function testing in LN patients are limited. This real-world analysis aimed to evaluate nephrologists' use of renal function tests to support LN diagnosis and monitoring and to examine the impact of disease progression in LN patients in Europe.

Methods: Data were drawn from the Adelphi Lupus Disease Specific Programme, a cross-sectional survey of nephrologists and their next five consulting patients with LN in France, Germany, Italy, Spain, and the United Kingdom in 2021. Nephrologists provided demographic and clinical information for each patient and the same patients completed a self-reported questionnaire. Using a checkbox, patients provided informed consent to take part in the survey.

Results: Nephrologists (n = 72) provided data on 376 patients with LN. Estimated glomerular filtration rate (eGFR) or proteinuria testing was not undertaken in around 10% and 50% of these patients, respectively. Regression analysis predicted reduction in renal function (disease progression) following LN diagnosis whilst bivariate analyses showed significantly worse outcomes for patients with progressed disease: worse pain, fatigue, treatment satisfaction, and patient-reported health state and activity impairment.

Conclusion: Our study revealed lower-than-expected nephrologist-reported use of renal function testing to support diagnosis/monitoring of patients with LN in real-world clinical settings in Europe. Lower quality of life (QoL) was observed in patients with more progressed disease. Increased use of renal function testing is needed so that all LN patients are monitored closely to manage disease progression and avoid the associated QoL impact.