Evolution of Physical Frailty and Patient-Reported Outcome Measures in Kidney Transplant Candidates: A Mixed-Methods Longitudinal Study Protocol

Longitudinal Tracking of Physical Frailty and Health-Related Quality of Life Through Patient-Reported Outcome Measures in Adult Candidates on the Kidney Transplant Waiting List

This study looks at how the physical and emotional health of people changes while they wait for a kidney transplant. Waiting for an organ can take a long time. During this period, some patients become "frail." This means they lose strength and are at a higher risk for health problems.

The main goal is to follow these patients over time to better understand their needs. Researchers will use a mobile application to collect Patient-Reported Outcome Measures (PROMs) directly from patients about how they feel and their quality of life. The study will also include personal interviews to learn about the patients' experiences and any difficulties they face when using technology.

The results of this study will help to: • Identify early which patients are losing strength or health. • Improve the support that nurses provide during the transplant waiting period. • Make sure that digital health tools are easy for everyone to use.

In short, this work aims to help patients reach the day of their surgery in the best possible condition.

Study Overview

• Status: Not yet recruiting
• Conditions: Quality of Life; Kidney Failure, Chronic; Frailty; Kidney Transplantation; Patient Reported Outcome Measures
• Intervention / Treatment: Other: Longitudinal Frailty Assessment; Other: Electronic Patient-Reported Outcome Measures (ePROMs)

Detailed Description

Study Design and Framework This research employs a convergent-parallel mixed-methods design to evaluate frailty dynamics and patient-reported outcomes in Kidney Transplantation (KT) candidates. The quantitative component is a longitudinal observational study, while the qualitative component is grounded in Heideggerian hermeneutic phenomenology to explore the lived experience of patients during the waiting list period.

Quantitative Procedures and Data Collection Participants will be recruited during their initial KT evaluation at Hospital del Mar (Barcelona). Frailty will be assessed using the Fried Phenotype (assessing weight loss, exhaustion, physical activity, walk time, and grip strength) at baseline and subsequently every six months while the patient remains on the waiting list.

To monitor Patient-Reported Outcome Measures (PROMs), the study utilizes the Patient-Reported Outcomes Measurement Information System (PROMIS)-29 v2.0 questionnaire. This instrument covers seven health domains: physical function, anxiety, depression, fatigue, sleep disturbance, ability to participate in social roles/activities, and pain interference. Data collection will be performed via a digital platform (electronic PROMs [ePROMs]), allowing for real-time monitoring. For patients facing technological or language barriers, an Advanced Practice Nurse (APN) will provide support to ensure data completeness and minimize selection bias.

Qualitative Exploration A purposive sample of participants will undergo in-depth semi-structured interviews. These sessions will focus on the subjective meaning of frailty, the impact of the waiting period on daily life, and the experience of using digital health tools. Interviews will be audio-recorded, transcribed verbatim, and analyzed using thematic analysis to identify core existential themes.

Quality Assurance and Data Management • Data Validation: A data dictionary has been developed, defining each variable, its source, and acceptable ranges to ensure consistency. • Source Data Verification: Data entered into the electronic Case Report Form (eCRF) will be cross-referenced with electronic medical records to ensure accuracy. • Standard Operating Procedures (SOPs): Specific SOPs are in place for patient recruitment, the standardized administration of physical performance tests (e.g., handgrip strength using a dynamometer), and the management of technical issues with the ePROM platform.

Statistical Analysis Plan (SAP) Quantitative data will be analyzed using SPSS (Statistical Package for the Social Sciences, v.25). Descriptive statistics will summarize baseline characteristics. Longitudinal changes in frailty scores and PROMs will be analyzed using linear mixed models or Generalized Estimating Equations (GEE) to account for repeated measures. The relationship between frailty status and PROMs will be assessed using correlation coefficients and multivariate regression models adjusted for age, comorbidity, and time on dialysis.

Missing Data Plan The study aims to minimize missing data through APN-led follow-up. If data are missing at random, multiple imputation techniques will be considered. For patients unable to use digital tools, paper-based alternatives or assisted entry will be provided to reduce non-response bias.

Sample Size Assessment The sample size is based on the prevailing activity of the kidney transplant unit, aiming to include all eligible candidates over the recruitment period (estimated N ≈ 150-200) to ensure sufficient power for detecting longitudinal changes in frailty prevalence and its association with PROMs.

• Study Type: Observational
• Enrollment (Estimated): 150

Contacts and Locations

• Study Contact: Name: Anna Bach Pascual, RN, MSN i PhDc; Phone Number: +34 648653656; Email: abach@hmar.cat

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of adult patients with End-Stage Renal Disease (ESRD), also classified as Stage 5 chronic kidney disease, managed at the Nephrology Department of Hospital del Mar (Barcelona). This clinical cohort includes patients currently receiving renal replacement therapy (either maintenance haemodialysis or peritoneal dialysis) as well as individuals in the pre-dialysis stage who have been formally referred for comprehensive kidney transplant evaluation. The target population is characterized by a high burden of medical comorbidity and varying degrees of physical frailty associated with chronic uraemia and long-term dialysis treatment.

Description

Inclusion Criteria:

• Patients aged 18 years or older.
• Diagnosed with Stage 5 chronic kidney disease (CKD).
• Currently undergoing clinical evaluation for or actively listed on the deceased-donor kidney transplant waiting list at Hospital del Mar (Barcelona).
• Cognitive and physical ability to understand and provide written informed consent.
• Ability to use or have regular access to a digital device (smartphone or tablet) for electronic Patient-Reported Outcome Measures (ePROMs) completion.

Exclusion Criteria:

• Severe cognitive impairment or active psychiatric disorders that prevent the reliable completion of questionnaires or physical tests.
• Major physical disability that precludes the objective assessment of gait speed or handgrip strength (e.g., bilateral lower limb amputation or severe dominant hand deformity).
• Acute medical illness requiring hospitalization at the time of enrolment.
• Total language barrier that prevents understanding the study components or the qualitative interview.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Kidney Transplant Candidates; This is a single-group observational cohort of adult patients with Stage 5 Chronic Kidney Disease (CKD) undergoing evaluation or active on the deceased-donor kidney transplant waiting list. All participants undergo a longitudinal follow-up every six months to monitor frailty dynamics and health perceptions. Data collection includes: Physical assessments: Evaluation using the Fried Phenotype framework (measuring handgrip strength and gait speed).; Patient-Reported Outcome Measures (PROMs): Assessment via the digital platform for the Patient-Reported Outcomes Measurement Information System (PROMIS)-29 (electronic PROMs [ePROMs]).; Qualitative exploration: Hermeneutic interviews for a selected subset to explore the lived experience of frailty. No clinical intervention or medication will be administered.

Other: Longitudinal Frailty Assessment; Systematic multidimensional assessment of physical frailty conducted by an Advanced Practice Nurse (APN) specialized in nephrology. The evaluation encompasses the following components: Fried Phenotype: Objective measurement of 5 criteria: unintended weight loss, self-reported exhaustion, physical activity level, gait speed (over 4 meters), and handgrip strength (using a calibrated hydraulic dynamometer).; Clinical Frailty Scale (CFS): Global clinical judgment score based on the patient's overall fitness and functional independence.; Short Physical Performance Battery (SPPB): Standardized test battery to objectively assess balance, gait speed, and lower limb strength through timed chair stands. Frequency: Assessments will be performed at baseline and every 6 months (+/- 1 month) throughout the patient's presence on the kidney transplant waiting list. Standardized protocols ensure data reproducibility.; Other Names: Fried Frailty Phenotype Assessment; Physical Performance Monitoring; Comprehensive Frailty Evaluation; Clinical Frailty Scale (CFS); Other: Electronic Patient-Reported Outcome Measures (ePROMs); Implementation of a digital health strategy to monitor patient-reported outcomes throughout the kidney transplant waiting list period. Core Instrument: Participants complete the Patient-Reported Outcomes Measurement Information System (PROMIS)-29 v2.0 questionnaire, assessing 7 health domains: physical function, anxiety, depression, fatigue, sleep disturbance, social roles/activities, pain interference, and pain intensity. Procedure: • Data Collection: Administered via a secure electronic Patient-Reported Outcome Measures (ePROMs) digital platform accessible via smartphone, tablet, or computer. • Frequency: Data collected at baseline and every 6 months, coinciding with physical frailty assessments. • Support: An Advanced Practice Nurse (APN) provides technical onboarding and follows up on non-compliance to address the digital divide. This observational strategy aims to capture the patient's subjective health status.; Other Names: PROMIS-29 v2.0 Questionnaire; Digital Health Monitoring; Patient-Reported Quality of Life Assessment

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Frailty Status (Fried Phenotype)	Change in frailty status over time assessed using the Fried Frailty Phenotype cumulative score, with a total score ranging from 0 to 5 points, where higher scores indicate greater physical frailty. Frailty status categories are defined as: Non-frail: 0 points Pre-frail: 1-2 points Frail: 3-5 points The outcome measure will assess longitudinal changes in the cumulative frailty score and frailty category during the patient's time on the kidney transplant waiting list.	Baseline, 6 months, 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Patient-Reported Outcome Measures (PROMs)	Change over time in health-related quality of life measured using the Patient-Reported Outcomes Measurement Information System-29 version 2.0 (PROMIS-29 v2.0). PROMIS-29 domain scores are reported as standardized T-scores ranging from approximately 20 to 80, where 50 represents the population mean and 10 the standard deviation. Higher scores indicate more of the concept being measured: Higher physical function and social participation scores indicate better functioning. Higher anxiety, depression, fatigue, sleep disturbance, and pain interference scores indicate worse symptoms. Each PROMIS domain score will be analyzed independently according to PROMIS scoring guidelines.	Baseline, 6 months, 12 months
Incidence of Clinical Transitions on the Waiting List	Incidence and time-to-event of major clinical transitions affecting transplant waiting list status, including kidney transplantation, temporary or permanent removal from the waiting list, and all-cause mortality.	12 Months
Digital Tool Usability and Implementation Barriers	Assessment of the feasibility and usability of the electronic Patient-Reported Outcome Measures (ePROMs) platform during longitudinal follow-up. Feasibility will be evaluated using questionnaire completion and adherence rates across the study period. Implementation barriers related to technology use and digital access will be identified and categorized through qualitative documentation obtained during Advanced Practice Nurse (APN) follow-up sessions.	12 months

Collaborators and Investigators

• Sponsor: Hospital del Mar

Publications and helpful links

General Publications

• Fried LP, Tangen CM, Walston J, Newman AB, Hirsch C, Gottdiener J, Seeman T, Tracy R, Kop WJ, Burke G, McBurnie MA; Cardiovascular Health Study Collaborative Research Group. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001 Mar;56(3):M146-56. doi: 10.1093/gerona/56.3.m146.
• Cella D, Riley W, Stone A, Rothrock N, Reeve B, Yount S, Amtmann D, Bode R, Buysse D, Choi S, Cook K, Devellis R, DeWalt D, Fries JF, Gershon R, Hahn EA, Lai JS, Pilkonis P, Revicki D, Rose M, Weinfurt K, Hays R; PROMIS Cooperative Group. The Patient-Reported Outcomes Measurement Information System (PROMIS) developed and tested its first wave of adult self-reported health outcome item banks: 2005-2008. J Clin Epidemiol. 2010 Nov;63(11):1179-94. doi: 10.1016/j.jclinepi.2010.04.011. Epub 2010 Aug 4.
• Bardes JM, Benjamin E, Schellenberg M, Inaba K, Demetriades D. Old Age With a Traumatic Mechanism of Injury Should Be a Trauma Team Activation Criterion. J Emerg Med. 2019 Aug;57(2):151-155. doi: 10.1016/j.jemermed.2019.04.003. Epub 2019 May 9.
• Chu NM, Deng A, Ying H, Haugen CE, Garonzik Wang JM, Segev DL, McAdams-DeMarco MA. Dynamic Frailty Before Kidney Transplantation: Time of Measurement Matters. Transplantation. 2019 Aug;103(8):1700-1704. doi: 10.1097/TP.0000000000002563.

Helpful Links

• Department of Nephrology, Hospital del Mar (Barcelona). Primary clinical site for participant recruitment and follow-up.
• Official PROMIS HealthMeasures website. Provides detailed information on the validity and scoring of the PROMIS-29 v2.0 questionnaire used in this study.
• Spanish National Transplant Organization (ONT). Provides the regulatory framework and national standards for kidney transplant waiting list management.

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): July 1, 2028

Study Registration Dates

• First Submitted: May 19, 2026
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 26, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 5, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Longitudinal Studies; Kidney Transplantation; Digital Health; Patient-Centered Care; Health-Related Quality of Life; Hermeneutics; Waiting Lists; Mixed Methods Research; Technology Assessment, Biomedical
• Additional Relevant MeSH Terms: Urogenital Diseases; Pathologic Processes; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Chronic Disease; Disease Attributes; Renal Insufficiency; Renal Insufficiency, Chronic; Pathological Conditions, Signs and Symptoms; Frailty; Kidney Failure, Chronic
• Other Study ID Numbers: 2024/11603

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

Individual participant data (IPD) will not be shared at this time to protect the confidentiality of the participants and the integrity of the ongoing doctoral thesis. The data collected involves sensitive clinical information and qualitative interviews within a specific, small-scale clinical setting (kidney transplant waiting list).

However, the study results will be disseminated through peer-reviewed publications and conference presentations. Requests for access to aggregate data or specific methodological details can be directed to the Principal Investigator and will be considered on a case-by-case basis, subject to approval by the Institutional Review Board (CEIm) and in compliance with the General Data Protection Regulation (GDPR)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No