Rationale
Patients with interstitial lung disease (ILD) require regular assessment of functional capacity and oxygen desaturation to monitor disease progression and treatment response. The 1-minute sit-to-stand test (1STST) has emerged as a practical and space-efficient alternative to the traditional 6-minute walk test (6MWT), offering comparable physiological data, including heart rate changes, oxygen desaturation, and perceived exertion.

The simplicity and minimal space requirements of the 1STST make it particularly attractive for at-home self-assessment. However, the feasibility, reliability, and safety of the 1STST when performed unsupervised at home remain unclear. With the advent of wearable technology, there is an opportunity to bring validated cardiopulmonary monitoring tools directly into patients' homes, enabling more frequent, decentralized assessments and improving access to care.
The Corsano CardioWatch 287-2B, a CE/FDA-certified wearable, enables continuous monitoring of vital signs such as heart rate, respiratory rate, oxygen saturation, heart rate variability, and physical activity. This trial investigates whether these parameters, paired with patient-led 1STST assessments, can provide a remote alternative to traditional in-hospital functional testing.

Study Objectives
Primary Objective
• To compare the at-home 1STST with the in-hospital 6MWT in ILD patients, focusing on repetitions vs. walking distance and nadir SpO2 at multiple time points (1-4 weeks post-baseline).
Secondary Objectives
• To compare the in-hospital 1STST with the in-hospital 6MWT using the same key metrics.
• To assess the reliability of the 1STST across hospital and home settings over time.
• To evaluate correlations between Corsano-derived parameters (steps/day, SpO₂, HR, RR, HRV) and standard lung function tests (FVC, DLCO) and patient-reported outcomes.
• To explore the predictive value of wearable data for disease progression, mortality, and transplant need.
• To assess 1-year changes in functional capacity and symptom burden.
• To determine the responsiveness and minimal clinically important difference (MCID) of the 1STST.
• To evaluate the usability and integration of the Corsano CardioWatch in daily ILD management.
• To compare ergometry outcomes with 1STST performance in a clinical subgroup.

Study Design
This is a prospective, single-center observational study involving patients with ILD treated at Erasmus MC. All participants will complete:
A baseline in-hospital 6MWT and 1STST, followed by
Five at-home self-administered 1STSTs over four weeks, with real-time physiological monitoring via the Corsano CardioWatch 287-2B
Continuous wearable data will be collected throughout the study period. Standard clinical and PROM data will be recorded at baseline and after one year for longitudinal evaluation.

Inclusion Criteria
Diagnosis of interstitial lung disease (ILD)
Ability to perform sit-to-stand and walk tests
Willingness and capacity to wear the Corsano CardioWatch 287-2B daily
Informed consent provided

Exclusion Criteria
Inability to perform functional tests due to comorbidities or mobility limitations
Inability to operate or tolerate wearable monitoring
Refusal or inability to provide informed consent

Current Status
Patient recruitment and baseline testing are ongoing. Early pilot observations support the feasibility of daily wearable monitoring and at-home sit-to-stand testing in the ILD population.

Timeline
Status: Actively recruiting
Start Date: 2025
Estimated Duration: 12–18 months

Study center
Erasmus Medical Center (EMC), Rotterdam, The Netherlands