EndoSense: Continuous Real-Time Monitoring of Health Markers in Endocrine and Metabolic Disorders

EndoSense is a monocentric, single-arm, non-randomized, before-and-after interventional study conducted at the University Hospital Zurich within the European ENDOTRAIN consortium. The study is designed to evaluate whether continuous wearable monitoring, combined with dynamic hormone sampling, can capture meaningful physiological and endocrine responses during standardized environmental challenges in adults with endocrine or metabolic disorders.

Current diagnostic approaches in endocrinology often rely on single time-point measurements, although many endocrine and metabolic processes vary across the day and in response to salt intake, meals, fasting, sleep, and physical activity. EndoSense addresses this gap by combining home-based physiological monitoring with structured dietary and activity modules. The study will assess whether wearable-derived data can provide clinically relevant information on blood pressure, heart rate, heart rate variability, activity, sleep, temperature, and glucose patterns, and whether these data correspond to dynamic hormonal changes.

Each participant will complete a structured home-monitoring protocol. The protocol includes a baseline home-monitoring period followed by sequential dietary sodium modulation, starting with a low-sodium phase and followed by a high-sodium phase. Standardized mixed-meal, fasting, postural, and short exercise modules are included to characterize postprandial, fasting, hemodynamic, and stress-related physiological responses. These modules may be adapted or omitted according to the participant's underlying condition, safety considerations, and preferences after consultation with the study physician.

During the home-monitoring phase, participants will wear several study devices. These include devices for periodic blood pressure and pulse monitoring, continuous glucose monitoring, activity and movement assessment, sleep monitoring, and temperature monitoring. Data from these devices are collected for research purposes only and will not guide clinical care during the study. Participants will also complete brief electronic diaries and questionnaires to document adherence, symptoms, sleep, physical activity, usability, and acceptance of the study devices.

A subset of participants who provide separate consent will undergo dynamic hormone sampling using the U-RHYTHM system. This device collects subcutaneous interstitial fluid samples over approximately 27 hours and is used to study day-night and short-term hormone patterns. The hormone sampling module is optional and will be performed at selected time points during the protocol and, when appropriate, during routine clinical assessments.

After the home-based phase, participants will undergo a clinical integration phase during routine care at the Department of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Zurich. Wearable data collected during routine diagnostic procedures will be compared with standard clinical assessments to explore how sensor-derived patterns relate to established endocrine and metabolic tests.

The study uses a within-participant design, meaning that each participant serves as their own reference across the different protocol phases. This design reduces between-person variability and allows the researchers to assess individual physiological responses to standardized changes in salt intake, meals, fasting, and short exercise. The study will also explore whether these responses differ across endocrine and metabolic conditions and whether biological sex influences physiological or hormonal patterns.

Safety measures are integrated throughout the protocol. Participants receive standardized instructions, predefined safety thresholds, and access to study physician contact if concerning symptoms or abnormal measurements occur. Potential risks include transient changes in blood pressure or glucose levels, discomfort related to dietary changes or exercise, and mild local reactions related to wearable devices or optional sampling procedures. Participation is voluntary, and participants may withdraw at any time without consequences for their clinical care.

The study aims to establish a sensor-integrated research framework for endocrine and metabolic disorders. In the long term, the knowledge generated by EndoSense may support the development of wearable-based monitoring environments as complementary tools for endocrine diagnostics, risk assessment, and personalized clinical care.

Inclusion criteria

Diagnosis or suspected diagnosis of at least one endocrine or metabolic disorder, including:

• Overweight or obesity, defined as body mass index of 25 kg/m² or higher
• Essential hypertension
• Diabetes mellitus, including type 1 diabetes, type 2 diabetes, gestational diabetes, maturity-onset diabetes of the young, or unclassified diabetes
• Hypoglycemia
• Endogenous hypercortisolism
• Primary aldosteronism
• Endogenous or exogenous adrenal insufficiency
• Congenital adrenal hyperplasia
• Polycystic ovary syndrome
• Adrenocortical tumor or adrenal incidentaloma
• Functional or non-functional pituitary tumor
• Pituitary insufficiency
• Polyuria-polydipsia syndrome
• Hyponatremia
• Functional or non-functional neuroendocrine tumor
• Osteoporosis
• Lipid disorder
• Thyroid disorder
• Hypoparathyroidism or hyperparathyroidism
• Inborn error of metabolism
• People undergoing gender-affirming hormone therapy

Exclusion criteria

• Known or suspected severe skin disorder or allergy that may interfere with wearable sensor placement, such as extensive eczema, psoriasis, chronic ulcers, or severe tape intolerance
• Known impaired wound healing or strong keloid tendency that would make repeated skin application or microneedle use unsuitable
• Pregnancy or lactation, for participation in home monitoring or dynamic hormone sampling
• Known or suspected bleeding disorder, such as von Willebrand disease
• Current treatment with anticoagulant or antiplatelet therapy at a dose that increases bleeding risk
• Severe acute or chronic medical condition that, in the investigator's opinion, would interfere with study procedures or compromise participant safety, such as decompensated heart failure, unstable angina, or acute systemic infection
• Current lithium treatment, because the intervention may alter lithium levels
• Recent travel across more than 4 time zones within the past 14 days, if study endpoints rely on circadian hormone profiles
• Ongoing shift work, if study endpoints rely on circadian hormone profiles
• Inability to give informed consent
• Inability to comply with study procedures