Subcutaneous Immunoglobulin Therapy Effectiveness Monitoring in CIDP Patients Using Smart Devices

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare autoimmune disease that affects the peripheral nerves. It causes progressive weakness and sensory loss in the arms and legs, which can severely limit daily activities. Many patients need long-term treatment with immunoglobulins, either through intravenous infusions (IVIG) or subcutaneous injections (fSCIG). The S.T.E.P.S. study aims to explore how digital health technologies-specifically smartwatches-can help monitor the disease course and treatment effects in CIDP patients who use fSCIG at home. Current clinical tests are useful but sometimes miss small changes in strength or function. Wearables may provide a more detailed and continuous picture of patients' health between clinic visits. Study Goals: The main goal is to find out whether smartwatch data (such as step count and physical activity) reflect disease severity and treatment response when compared to standard clinical scores like the Inflammatory Neuropathy Cause and Treatment (INCAT) scale and the Inflammatory Rasch-built Overall Disability Scale (I-RODS). Secondary goals include: Assessing how smartwatch data relate to patients' quality of life and sleep patterns. Comparing smartwatch results with other clinical scores such as muscle strength (MRC sum score) and grip strength. Evaluating how well patients can use the smartwatch over the long term during home treatment. An additional exploratory goal is to see whether smartwatch data can detect early signs of worsening disease before symptoms appear. Study Design: This is a 12-month observational study with five main clinic visits (at 0, 3, 6, 9, and 12 months). After enrolling, participants will begin or continue subcutaneous immunoglobulin therapy as decided by their treating physician. Each visit includes standard clinical assessments and questionnaires. Participants will receive a smartwatch at the start of the study to continuously track their activity and sleep patterns. A