Introduction: Lupus nephritis (LN) is a frequent complication of SLE, occurring in up to 60% of adult patients and ultimately progressing from acute inflammation to chronicity with fibrosis and end-stage kidney failure in 10%-30% of patients. Racial/ethnic minority patients with lupus have worse long-term outcomes, including progression to end-stage renal disease and overall mortality. A major challenge in the management of patients with SLE is delayed identification of early kidney disease, which ultimately leads to a greater burden on both patients and the health system.

Methods and analysis: Using a mixed methods approach, this study will develop, adapt and evaluate a home urine sampling protocol with a text-messaging reminder and data capture system for patients at elevated risk of de novo LN or relapse. First, a feasibility pilot using a single-group trial design (n=18) will be implemented, with a feasibility assessment and qualitative, debriefing interviews with patients to further refine the intervention. The second phase is a comparative effectiveness trial of the intervention (n=160) with the primary outcome of biopsy eligibility, that is, the participant has a clinical indication for a kidney biopsy (urine protein-creatinine ratio≥0.5), whether or not the patient actually undergoes the biopsy procedure. The randomised trial includes an economic evaluation of the adapted home urinalysis protocol.

Discussion and dissemination: It is unknown whether weekly home-based urine sampling can identify proteinuria sooner than standard care; if found sooner, kidney problems could be diagnosed earlier, hopefully leading to earlier care for less-involved disease and subsequent reduced morbidity. The data collected in this trial will inform future feasibility and effectiveness of text-messaging-based home urine sampling interventions.

Trial registration number: The randomised trial will be registered with ClincialTrials.gov prior to enrolment start.