This study will provide valuable insights into the demographics of MyRenalCare users, their digital adherence, and the overall impact of the app on health outcomes, healthcare costs, and environmental sustainability.

Inclusion Criteria:

5.1.1 Inclusion criteria - MyRenalCare users (retrospective and prospective cohorts)

Adults will be eligible for inclusion in the MyRenalCare cohorts if they meet all of the following:

1. Aged 18 years or over.
2. Under the care of the Wessex Kidney Centre
3. Registered with, or offered and subsequently enrolled onto, the MyRenalCare platform during the defined retrospective or prospective periods.
4. Able to understand study information and, where applicable, provide informed consent for use of their data for research purposes.

Specific CKD stage definitions and thresholds (e.g. based on eGFR, albuminuria or uPCR) will be documented in the study manual to ensure consistent application.

5.1.2 Inclusion criteria - matched usual care controls

Adults will be eligible for inclusion in the matched control cohorts if they meet all of the following:

1. Aged 18 years or over.
2. Under the care of the Wessex Kidney Centre for chronic kidney disease.
3. Not registered with or using MyRenalCare at any point during the relevant observation period.
4. Have sufficient clinical and administrative data available in the renal electronic patient record to enable matching and outcome assessment.

Controls will be identified retrospectively from the renal electronic patient record and matched to MyRenalCare users using a predefined matching strategy.

5.1.3 Inclusion criteria - qualitative interview participants (patients and staff)

Patients will be eligible to take part in the qualitative interview component if they meet all of the following:

1. Aged 18 years or over.
2. Currently using, or recently offered, the MyRenalCare platform as part of their CKD care at the Wessex Kidney Centre.
3. Able to understand spoken and written English to the extent required for participation in an interview.
4. Able and willing to provide written informed consent for participation in a recorded interview.
5. Belong to a demographic or clinical subgroup of interest for the study (e.g. varying age, ethnicity, CKD stage, or digital engagement level), as part of purposive sampling to support diversity and equity analysis.

Clinical staff will be eligible if they meet all of the following:

1. Employed by PHU or working in direct partnership with the Wessex Kidney Centre.
2. Directly involved in the care of patients with chronic kidney disease and/or in the implementation or support of MyRenalCare.
3. Able and willing to provide informed consent for a recorded interview.
4. Able to reflect on experiences and observations relevant to the delivery, uptake, or equity implications of digital health in CKD.

Exclusion Criteria:

1. Patients with acute kidney injury without established chronic kidney disease.
2. Patients with a very limited life expectancy where participation in routine digital monitoring is not appropriate, as judged by the clinical team.
3. Patients who have previously indicated that they do not wish their routinely collected clinical data to be used for research where such opt-out applies to this study.
4. Patients who are unable to be identified reliably in the available data sources (for example, inconsistent or missing key identifiers).
5. Any other situation where, in the opinion of the responsible clinician, participation in the study processes (including data use) would be inappropriate or unduly burdensome.
6. Clinical staff who are not directly involved in the care of patients with chronic kidney disease or in the implementation of the MyRenalCare platform.
7. Staff members currently on extended leave or unable to participate during the data collection period.
8. Individuals who do not wish to have their views included in recorded interview transcripts or are unable to provide informed consent for participation.
9. Any situation where, in the opinion of the study team or the individual's manager, participation would be inappropriate or burdensome due to role, availability, or conflict of interest.

• Retrospective: ~450-500 existing users + matched controls(24 months data).
• Comparison with entire WKC CKD population
• Prospective: ~500-550 new users + matched controls (6 months).
• Exploratory: ~500 dialysis or pre transplant MyRenalCare users (no matched controls).
• Qualitative: 15-25 patients + 10-15 staff.