Overview

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 follow-up phone call one week later will check that the device is working properly.

Duration

Recruitment will last about 6 months, and each participant will be followed for 12 months.

Why This Matters:

By combining established clinical measures with continuous digital monitoring, the S.T.E.P.S. study may help improve understanding of disease activity and treatment response in CIDP. This could lead to more personalized therapy schedules and better long-term care for patients.

Eligibility

Inclusion Criteria:

• Diagnosed typical or possible typical CIDP according to the 2021 EAN/PNS criteria
• Age ≥18 years
• Ability to use a smartwatch as decided by the investigator
• switched from IVIG to fSCIG within the prior 6 months or plan to switch during study recruitment phase
• on investigator-confirmed stable IVIG therapy pre-switch

Exclusion Criteria:

• Age \< 18 years
• Inability to operate smartwatch or smartphone device
• current pregnancy and breastfeeding status
• CIDP variants according to the 2021 EAN/PNS criteria