Idiopathic nephrotic syndrome (NS) is one of the most common chronic kidney diseases in children, with a prevalence of approximately 16 cases per 100,000 children. NS is characterized by heavy urinary losses of protein leading to hypoalbuminemia, edema, and hyperlipidemia. Children are treated with high-dose corticosteroids on presentation, and \>80% respond to treatment with resolution of proteinuria and symptoms. However, 80-90% of the children initially sensitive to corticosteroids will experience disease relapse, with more than half relapsing frequently or becoming dependent on corticosteroids to maintain remission. During a relapse, patients can suffer from anasarca, acute kidney injury, serious infections, or thromboembolic events.

Management of children with NS entails long-term outpatient surveillance and treatment. Home care includes the important standard-of-care task of urine monitoring to follow the relapsing-remitting nature of the disease. New proteinuria signals disease relapse before the development of overt symptoms such as edema. Thus, patients are instructed to alert their providers to the occurrence of proteinuria in a timely manner so that corticosteroids can be initiated or adjusted to treat each relapse and prevent acute disease complications. It is also important for the patients to track urine protein for resolution so that corticosteroids can be stopped or reduced to minimize steroid toxicity.

Not unlike other chronic, relapsing-remitting pediatric disorders, self-management is difficult for NS patients and their caregivers. Mobile health (mHealth) is a promising, rapidly growing field in disease management. In NS, there are numerous aspects of self-management that may be facilitated by a mobile app. First, the visual analysis of a urine test strip is subject to human error, including reading the wrong reagent block and erroneous assessments of color. This can be improved through using a smartphone's camera and computer to read and analyze test strip results. Second, caregivers must remember to check their child's urine, recall results, and understand what the results mean: the demands are taxing in that disease relapse is defined as urine protein ≥2+ for 3 consecutive days and remission is defined as negative/trace urine protein for 3 consecutive days. Apps, with their inherent interactivity, can provide reminders for urine testing, capture the results, and analyze trends to detect disease relapse/remission. Apps can alert a caregiver to seek medical attention and directly transmit test results to providers. Lastly, apps can provide medication reminders for NS patients, who are on highly complex medication regimens.

UrApp was iteratively developed by an expert panel of two pediatric nephrologists and three research engineers with expertise in human-computer interaction. App features were devised by the clinicians to support elements of chronic care management according to the Chronic Care Model and tasks that are challenging for caregivers. This study will include 60 caregivers of children with newly diagnosed nephrotic syndrome. Participants will be randomized 1:1 to UrApp or standard of care and followed for 1 year. In addition to the study outcome measures, user feedback will be collected via survey, interview, and by stakeholder meetings to inform app refinement.