Advanced practice nurses for fall incidence prevention in robust very old adults: protocol for the APN-FIT hybrid randomized controlled trial

Abstract

Background

Falls in older adults represent a major cause of disability and a pivotal indicator of the transition from robustness to frailty. Implementing large-scale prevention programs remains challenging because it requires the mobilization of extensive skills and human resources. In France, Advanced Practice Nurses (APN) are emerging as key actors in primary care, with the potential to provide multimodal, preventive, and patient-centered follow-up for older adults.

Methods

The APN-FIT trial (Advanced Practice Nurses for Fall Incidence prevenTion in robust very old adults) is a hybrid type 1, multicenter, randomized, open-label, superiority trial conducted in seven medical centers in the Pays de la Loire region, France. The study will assess whether a 12-month, personalized, multimodal follow-up by APN reduces fall incidence among robust participants aged ≥ 80 years (Clinical Frailty Scale ≤ 3). A mixed-methods implementation study and a cost-utility analysis will be performed. A total of 386 participants will be randomized 1:1 after an initial comprehensive geriatric assessment (CGA). The intervention group will be followed by APN at 1, 3, 6, 9, and 12 months. Primary and secondary outcomes, including intrinsic capacity domains, will be reassessed at 12 months.

Discussion

We expect that APN follow-up will reduce fall incidence and delay transitions to pre-frailty or impaired mobility. This pragmatic hybrid trial will provide evidence on the clinical, economic, and implementation impact of APN-led fall prevention in community-dwelling very old adults.

Trial registration

This study has been registered on clinicaltrials.gov, NCT06617806, registration date 2024-09-26.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-025-06781-0.

Introduction

Background and rationale

Fall prevention is of utmost importance in the context of geriatric care. Overall, 4% of total healthcare expenditures are attributed to falls [1]. In the oldest population, the annual fall incidence is approximately 25%, and increases with age [2, 3]. A third of the falls result in a decline in functional status [4]. The first fall may indicate a transition from functional independence to disability, with a mean age of occurrence reported at 83 years [5, 6]. Notably, the incidence of falls increases markedly after the age of 80, making this age group particularly vulnerable and clinically relevant for targeted interventions. Despite this, individuals aged 80 years and above remain underrepresented in clinical trials on fall prevention [7].

The effectiveness of multimodal prevention in reducing the risk of falls has been demonstrated in the existing literature [8, 9]. Integrated programs combining exercise and adapted physical activity programs [10] under the supervision of physiotherapists, physical therapists, or professionals specializing in adapted physical activity [11, 12] have demonstrated the greatest impact on fall prevention [13]. Most of these programs are based on a Comprehensive Geriatric Assessment (CGA) assessing a wide range of factors, including the social environment, disabilities, physical performance, the nutritional status, comorbidities, and polypharmacy [14].

Nevertheless, a number of studies have identified significant challenges in implementing these programs, including a lack of material and human resources, as well as limited access to multidisciplinary expertise within a multimodal approach. For instance, physiotherapists are trained in physical activity but not in the management of polypharmacy or cognitive impairment. Furthermore, older patients often poorly adhere to these programs, which can be attributed to numerous factors, including a negative perception of the program itself [15]. Evidence of the effectiveness of such interventions is inconclusive and depends on the caregiver’s profile, the intensity of the clinical follow-up and/or patient’s compliance. It is therefore imperative to validate these programs using pragmatic approaches that integrate an assessment of their implementation in order to optimize the impact of the interventions in the patient’s healthcare environment.

In the 2020 s, Advanced Practice Nurses (APN) have become a new paramedical profession in France, adding to the primary care service workforce and landscape. These nurses should allow strengthening various dimensions of primary care, including therapeutic education, prevention, screening, and the clinical and therapeutic follow-up of patients [16]. This will be achieved after the completion of an enhanced training program specializing in evidence-based nursing practice. In addition, they are equipped to perform a comprehensive geriatric assessment (CGA) and implement a personalized, multimodal prevention program in close collaboration with other healthcare professionals. In a geriatric care setting, where chronic diseases and multimorbidity are common, close multidisciplinary collaboration is often required. Furthermore, selecting a population of robust very old adults allows for the evaluation of preventive strategies in a subgroup that combines both elevated fall risk and preserved potential for benefit.

Objectives

Our main hypothesis is that APN will facilitate the adoption of CGA recommendations and improve adherence to the proposed programs.

The primary objective of our study is to assess the effectiveness of a 12-month follow-up by APN on the incidence of falls in robust very old adults compared to a standard follow-up. In addition, an economic analysis will assess the cost-effectiveness, from a collective perspective and over a 12-month time horizon. Finally, we will assess the results achieved following the intervention implementation, based on the eight implementation-related outcomes identified by Proctor and colleagues [17]: acceptability, relevance, adoption, effectiveness, feasibility, fidelity, reach and sustainability.

Study design and setting

The APN-FIT trial (Advanced Practice Nurses for Fall Incidence prevenTion in robust very old adults) is a pragmatic, hybrid, type 1 [18], multicenter, randomized, open-label, superiority trial. The APN-FIT trial represents the first French randomized controlled trial evaluating an APN-led 12 months fall prevention program among robust very old adults, integrating both cost-utility and implementation analyses. The study will be conducted in seven local medical centers in the Pays de la Loire region in France. The study intervention will be administered by trained, certified and registered APN.

Methods

Participants

Community-dwelling older subjects eligible for the APN-FIT study will be enrolled during a clinical visit and/or screening by a general practitioner (GP) and an APN. The APN will provide detailed information along with the APN-FIT study information sheet to the potential participants (see supplementary data). Preselected subjects will have a few days to decide whether or not they want to participate in the study.

Inclusion and exclusion criteria are listed in Table 1. The study population will include patients consulting primary care medical centers, aged over 80, considered vigorous (according to the Clinical Frailty Scale) and able to follow a tailored intervention program.

Table 1.

Inclusion and exclusion criteria

Inclusion criteria

• Aged 80 or over • Vigorous according to the Clinical Frailty Scale (score of 1, 2 or 3) • Having a GP voluntarily willing to participate in the study working in partnership with the investigating APN or willing to work in partnership with the investigating APN of the Territorial Geriatric Mobile Team of Nantes University Hospital • Being affiliated with a health insurance scheme • Having been informed and having signed a consent form to participate

Exclusion criteria

• Being under guardianship or trusteeship; • Inability to travel to the GP’s or APN’s office or inability to follow a tailored physical activity program • Poor understanding of French

Recruitment and randomization

Healthcare providers

Before starting recruitment, GPs already working with the identified APN in the region will be informed about the protocol and the selected population through seminars and information videoconferences organized with the help of Nantes University General Medicine Department. Contact details of local APN and the study objectives will be provided to all GPs.

Participants

Preselection will be performed by GPs and APN; recruitment will be performed by APN in their local healthcare center. Participants will be randomized in a 1:1 ratio using a random block size ranging from 4 to 6, stratified by the APN, once the APN will have performed the CGA.

Comprehensive geriatric assessment in all participants

The APN will perform a CGA in each participant, followed by a detailed analysis of the data obtained. The APN will then inform the patient’s GP of the CGA conclusions, and together they will collaborate to implement necessary interventions.

The APN’s recommendations may include the following: referral for a specialized memory assessment in case of cognitive impairment; a psychological follow-up if any mood disorders are detected by the APN; an ophthalmological and/or ENT (ear, nose and throat) consultation if any hearing or vision problems are detected; use of compression stockings if orthostatic hypotension is present; nutritional counseling, with particular emphasis on protein intake, combined with long-term weight assessment; vitamin D and calcium supplementation in line with French guidelines [19] to prevent osteoporosis in older adults, especially those at risk of recurrent falls; proposal to participate in a standardized, personalized physical activity program, regardless of the results of physical performance tests; review of drug therapies, especially for patients taking psychoactive drugs, antihypertensive drugs or broad-spectrum anticholinergics. The STOPPFall [20] tool will also be proposed and its use will be coordinated by the APN in agreement with the patient’s GP; a comprehensive social assessment approach will be used and, if deemed necessary, an assistance plan will be implemented.

This multimodal integrative approach for older patients is based on the APN competence/expertise framework, and all healthcare strategies will be managed in close collaboration with the patient’s relatives, including physical education instructors, GPs, pharmacists, nurses, etc.

Intervention group: follow-up with the APN

In the intervention group, each APN will schedule a follow-up visit 1, 3, 6, 9 and 12 months after inclusion, using their full range of skills and scope of practice.

At each follow-up visit, the APN will ensure that the initial recommendations are being followed, and will adjust them according to the patient’s evolution.

The phases of the APN-FIT protocol are summarized in Fig. 1.

Fig. 1.

Study flowchart for the intervention group. This figure illustrates randomization and interventions for intervention and control groups. Abbreviations: APN: advanced practice nurse; CGA: comprehensive geriatric assesment; GP: general practitioner

Control group

Each APN will inform the GP of the patients included of the conclusions of the CGA and the associated recommendations.

A home-based individual exercise and physical activity program

A 7-week home-based physical activity program, with twice-weekly sessions (45 min each), will be proposed to all participants, based on the individual physical performance measurements performed by the APN at the time of inclusion. This program will be fully funded as part of the APN-FIT study. However, included participants will have the choice to follow their own physical activity program, to continue with their preferred practice, or not to participate in the physical activity program. Professionals specialized in adapted physical activity will offer their intervention after a phone call, which will also include an assessment of sedentary behaviors and a quantification of physical activity, using the Ricci-Gagnon scale [21]. Briefly, each session will include active relaxation, muscle strengthening and overall balance. It will also aim to increase walking speed and include dual-task exercises. A more complete description of the program is available in supplementary data. After the 14 sessions, a final assessment will be performed, and participants will have the possibility to continue the physical activity of their choice at their own expense.

Data collection and outcome measurements

All outcomes we plan to collect in this protocol are summarized in Fig. 2.

Fig. 2.

Visual map of outcomes collected during the APN-FIT trial. Primary outcome: number of falls at 12 months. Secondary outcomes: severe falls, frailty progression, physical and cognitive performance, nutrition, quality of life (EQ-5D-5L), healthcare utilization, and cost-utility analysis. Includes an ancillary implementation study

Primary outcome: falls

The primary outcome is the number of falls recorded at 12 months. It will be assessed progressively during each phone call and/or medical consultation (at least every 2 months), and finally assessed during the second CGA at M12.

Secondary outcomes

Secondary outcomes will include:

• Number of severe falls. Severe falls will be defined as falls resulting in injuries serious enough to require a medical consultation; for which the person remains lying on the floor without being able to get up for at least one hour; prompting a visit to the emergency room; associated with a loss of consciousness, based on the World guidelines for falls prevention and management [9].

• Level of independence, assessed based on:

  • Katz’ index of independence in activities of daily living [22].
  • Lawton Instrumental Activities of Daily Living [23].

• Level of healthcare utilization, assessed based on the number of consultations, and the use of dental, ophthalmological and ENT care during the follow-up.

• Level of emergency care utilization, determined based on the number of hospitalizations in an emergency care unit during the follow-up.

• Frailty, assessed using:

  • The Clinical Frailty Scale (CFS) [24].
  • The ICOPE (Integrated Care for Older People) Monitor score [25].
• Physical performance, assessed using:

  • The Timed Up and Go test (TUG).
  • The Short Physical Performance Battery (SPPB), at both CGAs.
• Cognitive performance, assessed using:

  • The MMSE (Mini Mental State Examination).
  • The FAB (Frontal Assessment Battery) for executive functions [26].

• Mental health status, assessed using a mini-GDS (Geriatric depression scale).

• Nutritional status, assessed based on the BMI (body mass index), weight loss and MNA (Mini Nutritional Assessment).

• Quality of life, assessed using the EQ-5D-5 L questionnaire.

Timepoints and data collection

Six assessments will be performed at 2, 4, 6, 8, 10 and 12 months. Each participant will be contacted every two months by the clinical research assistant or the study nurse to collect data on falls and secondary endpoints using a blinded approach. At the end of the study (M12), a new CGA will be performed in all patients during the month following the last APN visit by the study nurse (i.e., between months 12 and 13). No further interventions are planned after month 15. The schedule of study activities is presented in Table 2.

Table 2.

Schedule of study activities for all participants

	D-15 (screening)	Enrolment	D0- M2	D0- M12	M1	M2	M3	M4	M6	M8	M9	M10	M12	M12 -M15
APN – Investigator – For all participants
Information	X
CFS	X
Informed consent		X
Randomization		X
Clinical evaluation		X
CGA		X
EQ-5D-5 L		X
Physical activity proposal			X
Control group - Standard follow-up
GP reads APN’s recommendations		X
Interventin group – Follow-up with the APN
APN consultation				X	X		X		X		X		X
GP reads APN’s recommendations		X		X	X		X		X		X		X
Implementation of a qualitative analysis (20 to 30 participants)
Semi-structured interviews with participants and close relatives														X
For all randomized participants
Phone calls by the clinical research assistants
- Falls and fall-related injuries - EQ-5D-5 L						X		X	X	X		X	X
At participants’ home or at the APN’s office
CGA													X
CFS													X
Information on study implementation													X

Complete CGA at inclusion and M12, and physical activity program for all. CGA will include Mini Mental State Examination (MMSE), Mini Nutritional Assessment (MNA), Frontal Assessment Battery (FAB), Mini-Geriatric Depression Scale (mini GDS), Katz’ activities of daily living (ADL), Lawton instrumental activities of daily living (IADL), Integrated care for older People (ICOPE) scale, BMI, Timed Up and Go (TUG), Short Physical Performance Battery (SPPB)

Abbreviations: APN Advanced practice nurse, CFS Clinical Frailty Scale, BMI Body mass index, CGA Comprehensive geriatric assesment, GP General practitioner, EQ-5D-5 L EuroQol questionnaire for Quality of life

Sample size

It is estimated that there will be 2.37 falls in the year per participant in the control group [27], with a reduction in the number of falls of at least 23% expected in the intervention group followed by an APN [28]. Assuming a power of 80% and a two-sided alpha risk of 5%, a sample size of 228 subjects per group will be required. Assuming an intra-cluster correlation of 0.02 [29] and a workforce of 7 APN for enrolment, 55 patients per APN will be required, totaling 386 patients to obtain groups of equal size.

Economic analysis

A cost-utility analysis (CUA) will be performed in line with French guidelines [30], from a collective perspective and over a one-year time horizon. The CUA will consist of calculating the incremental cost per Quality-Adjusted Life Year (QALY) by comparing the innovative fall prevention strategy involving an APN to the conventional strategy. The QALYs will be computed from the EQ-5D-5 L instrument (i.e. EuroQol questionnaire), which provides the health utility coefficients required for cost-utility modeling. The choice of CUA is justified by the potential impact of the compared strategies on the quality of life of older adults.

Therefore, the primary outcome measure will be the following ratio:

Rate of Differential Cost – Utility =.

Ancillary study of the intervention implementation

An ancillary study will be conducted to better understand the efficacy-related factors observed in the main study. Its aim is to determine the optimal conditions for implementing the intervention for its practical deployment in the field. The data collection for this ancillary study will be essentially opportunistic, and will coincide with the data collection needed to achieve the primary objective of the main study. Importantly, no hypothesis testing is planned in this descriptive study. The study methodology will use a mixed approach, seamlessly integrating complementary quantitative and qualitative methods.

The indicators described by Proctor and colleagues [17] will be used for the assessment. Each domain will be described by a series of adapted quantitative and qualitative indicators and observations (Table 3). An indicator may contribute to more than one domain, in which case, it will be repeated in each relevant domain.

Table 3.

Domains and indicators selected for the implementation ancillary study

Domain	Definition	Quantitative indicator	Qualitative indicator
Acceptability	Perception by relatives that a given treatment, service, practice or innovation is satisfactory	- Description of the reasons for refusal of eligible patients - Number of participants who withdrew after randomization - Adherence of participants to APN visits	- Ethnographic observations of APN interventions - Focus groups with GPs and APN - Semi-structured interviews with relatives and participants
Relevance	Perception of the adequacy of the innovation to address a particular question or problem		Qualitative analysis of data collected during group and individual interviews with physicians and APN, relatives, and participants
Adoption	Intention, initial decision, or action to try or use an innovation	- Proportion of eligible patients included - Description of the reasons for refusal	- Qualitative analysis of the feedback of relatives and participants
Efficiency	Assess the cost that society is willing to pay to guarantee the health gain associated with the intervention	Differential cost-utility ratio and acceptability curve
Feasibility	The extent to which an innovation can be successfully implemented within a given organization	- Proportion of incomplete follow-up after the CGA - Description of the reasons for not performing the CGA	- Ethnographic observations of the APN’s work - Analysis of obstacles and facilitators perceived by APN and GPs when implementing the follow-up
Fidelity	The extent to which an intervention has been implemented in accordance with the original protocol	- Number of interventions implemented in accordance with the recommendations from the initial CGA - Description of conformities according to the CGA components	- Ethnographic observations of the APN’s work - Analysis of the statements gathered during the focus groups with relatives
Scope	Number of subjects affected by an intervention and their representativeness with respect to the target population	- Characteristics of included patients - Characteristics of participants with a complete follow-up	Analysis of statements collected during interviews with participants and their relatives, in particular to characterize the involvement of relatives and assess the impact of the intervention on this involvement
Permanence	The existence of continuity beyond the study regarding the health benefits of the intervention for the population and the means used to achieve it	- Effective allocation of the study resources - Regularity of inclusions - Effective workload: mean number of follow-up visits/APN/patient during the study - Continuation of APN actions during the study	Analysis of the feedback of relatives and participants made during interviews

Indicators are derived from Proctor and colleagues (17). For each domain, definition and a series of adapted quantitative and qualitative indicators are given

Abbreviations: APN Advanced practice nurses, CGA Comprehensive geriatric assessment, GP General practitioner

The intervention implementation will be assessed at various levels:

• At the patient’s level: we will focus on subjects meeting the inclusion criteria of the main study. Qualitative interviews will be conducted with a subgroup of this population and with their relatives.

• At the healthcare provider/organizational level: the study will involve participating APN and GPs.

To achieve our research objectives, we will conduct individual and group interviews. These interviews will allow us to cross-examine experiences with the program based on the feedback of the participants and their relatives. Enrolment will take into account sociodemographic factors (e.g., gender, former occupation, widowhood status) and geographical data (urban, semi-urban, rural) to enable generalizability. Feedback saturation will be targeted.

To capture the experiences of subjects and their relatives, the interviews will be subjected to an interpretative phenomenological analysis, as developed by E. Husserl [31]. Based on phenomenological invariants, a general structure of the experiences studied will be extracted, allowing understanding the conscious and unconscious processes underlying the experience.

The survey of professionals will take place in two stages:

1. Initial observations: During the first few months of the project, when inclusions will begin, we will observe the working conditions, professional practices and skills of APN. To do so, three to four APN will be observed over several working days.

2. Focus groups: Nine to 12 months after the launch of the project, we will organize focus groups with healthcare professionals. Two focus groups will exclusively include physicians, while the other two will include both physicians and APN.

The data analysis concerning collaboration between the healthcare providers will be based on the sociology of professions. We will use a sequential thematic analysis of feedbacks and a visual examination of non-verbal communication elements and social interactions to identify factors that facilitate or limit the program implementation.

Ethical aspects

The study will be conducted in full compliance with the principles of the World Medical Association Declaration of Helsinki. It has been approved by a randomly assigned French ethics committee (“Comité de Protection des Personnes Nord-Ouest IV”) on April 11, 2024. The study is registered on the Clinical Trials repository under number NCT06617806, registration date 2024-09-26.

Informed consent

Detailed information will be provided by the APN at the time the information sheet will be provided to the participants (see supplementary data). The patients will be given a few days to consider whether or not they want to participate in the study. At any time, the participants may exercise their right to withdraw from the study.

Data management

Each participant will receive a unique identification code at baseline. All data collected during the study will be computerized in compliance with local data protection laws. In accordance with their purpose, the data will be recorded in separate computer files hosted in partitioned computer directories to prevent any physical association between administrative data and pseudonymized health data.

Adverse events

Adverse events are defined as any unfavorable experience occurring in a participant during the study, regardless of whether or not it is considered to be related to the APN-FIT study or the study procedures. All adverse events reported by the participant or observed by the investigator or clinical research assistants will be documented. The occurrence of adverse events will be monitored during the phone calls and during the last CGA by the study nurse.

Study status

Inclusion in the study has started on October 15, 2024. We plan to complete inclusion and baseline data collection by December 2025. With the 12-month follow-up period and the 6-month data analysis, the study will end in June 2027. This study has been registered on clinicaltrials.gov (NCT06617806, registration date 2024-09-26).

Steering committee

The data management team and the steering committee are composed of the same members, namely all the authors of the study. The committee operates independently of the sponsor and has no competing interests. Regular meetings will be held every two weeks. In accordance with French clinical research regulations, the trial will be subject to independent audits.

Statistical analysis

Statistical analysis plan

This section presents the analytic plan for the final analysis, which will focus on treatment group comparability, safety and treatment efficacy. The primary and secondary outcomes will be analyzed according to the intent-to-treat principle (i.e., practices/participants will be analyzed according to their initial treatment assigned, regardless of their adherence to the protocol). Clustering will be taken into account in all analyzes with the participant as the unit of analysis. SAS and R software will be used for all analyzes. Comparability of treatment groups will be assessed by comparing the distribution of baseline characteristics in the two groups using appropriate graphical procedures, summary statistics and descriptive multivariate methods (e.g. clustering). The randomization is designed to balance important covariates at the patient level. Therefore, in a secondary analysis, the following pre-specified set of baseline covariates will be selected for adjustment to determine their influence on treatment comparisons: age, gender, education level and number of chronic conditions. The safety analysis will compare the frequency of serious adverse events (SAEs) between the two groups using appropriate methods for discrete and continuous measures. SAEs will be tabulated both per event and per patient.

Analysis of the primary outcome

It will be performed using a mixed model that incorporates clustering at the APN level. Participants lost to follow-up without having been injured as a result of a prior serious fall will be censored at the date of their last visit. In a sensitivity analysis, we will also perform adjustments for the pre-specified set of baseline covariates to examine their influence on treatment comparisons. Standard approaches will be used to examine the adequacy of the models. In a further analysis, we will estimate the effect of the intervention at the APN level. The effect of the intervention will be assessed in the following five pre-specified participant subgroups using appropriate homogeneity tests (e.g., interaction): age (80–89, ≥ 90), gender (male, female), fear of falling while alone (yes/no), multimorbidity (0–1 chronic condition, ≥ 2 chronic conditions), and hip fracture or other fracture since the age of 50 (yes/no). Adjustment for test multiplicity will be performed using the Benjamini-Hochberg method. The cumulative incidence of serious injuries due to falls will be estimated using non-parametric maximum likelihood methods (Aalen Johansen estimator), and will be used to estimate the absence of falls throughout the follow-up period. An overall type-I error rate of 0.05 (two-sided) will be used as the statistical significance level for the primary endpoint.

Analysis of the secondary outcomes

All falls (regardless of severity) will be analyzed using the same method as the primary outcome. Quantitative covariates will be analyzed using generalized linear mixed effects models, assuming missing at random (MAR), with adjustment for baseline indicator. Based on the observed distribution of missing data, an appropriate imputation procedure for the number of falls will be used before performing the analysis [32]. To control for multiplicity, we will test the secondary outcomes using a significance level of 1% (two-sided) and report the 99% confidence intervals. Hospitalizations will be analyzed using a Poisson regression model taking into account clustering at the APN level, with the follow-up duration considered an offset. The analysis will be performed using R software or another software if R does not allow implementing the appropriate model (e.g., Stata).

Economic analysis

The mean costs and QALYs per group, their differences, and the incremental cost-effectiveness ratio (ICER) will be presented collectively. The differences in costs and QALYs between the groups will be estimated using multiple regressions (seemingly unrelated regressions, SUR) and bootstrap (bias-corrected and accelerated bootstrapping) [33] to take into account the covariance between the costs and the QALYs and to adjust for certain parameters such as baseline quality of life levels (EQ-5D-5 L).

To take into account the uncertainty surrounding the ICER estimate, we will plot an acceptability curve showing the probability that the follow-up strategy with the APN is cost-effective compared to the conventional strategy for different willingness-to-pay values for a QALY.

Finally, the robustness of the results will be assessed through sensitivity analyzes by varying certain study parameters, such as the imputation strategy for missing data.

Discussion

This article describes the design of a hybrid, type 1, randomized, controlled trial comparing an APN-implemented fall prevention program to the standard of care.

All participants will perform a full CGA at baseline and benefit from physical activity programs over the 12-month period. The APN will provide their nursing expertise, skills and time to a vigorous population at risk of falls. Therefore, in addition to reducing falls, we expect that APN will reduce the number of transitions to pre-frailty, frailty or impaired mobility.

Study strengths

The main strength of this study is its pragmatic type 1 hybrid design using a mixed methodology, which is not yet widely used in practice. It adds a medico-economic analysis and a mixed quantitative and qualitative study of the intervention implementation to a more standard quantitative approach in a randomized, open-label study to assess fall incidence reduction. The use of this method will allow defining a comprehensive global vision of the intervention, encompassing not only its effectiveness in preventing falls but also the essential components needed for its success in real-world settings and its long-term sustainability. To the best of our knowledge, no comparable study has been published in the literature.

The comprehensive nature of the geriatric assessment is another strength of this study. We will assess not only the incidence of falls, but also many other geriatric outcomes, including fractures, frailty, unplanned hospitalizations and loss of mobility. To do so, we will perform a CGA at baseline. Falls are both a cause and a consequence of the transition from robustness or functional independence to mobility loss, driven by increasing frailty and frequent hospitalizations. In a study conducted by Gill and colleagues, hospitalizations have been shown to be associated with a 168-fold increased risk of severe loss of mobility in a cohort of 754 subjects aged over 70. Of these hospitalizations, 44% were related to a fall [6]. Falls undoubtedly have a profound impact on the health outcomes of our older patients, and this situation will worsen over time [34]. However, the precise relationship between the prevention of falls, the prevention of other geriatric syndromes and the social acceptance of recommendations remains unclear, particularly in very old patients. This may be pivotal to achieving the full effectiveness of fall prevention programs in practice.

One of the main objectives of this study is to determine the optimal conditions for integrating APN into primary healthcare provision for older adults, which will be challenging. Indeed, their work is part of a complex network of medical professionals, including GPs, geriatricians, physiotherapists, sport educators, pharmacists and home nurses, which can complicate effective communication. Our study aims to address these challenges, hypothesizing that their tailored, distinctive approach will improve adherence, communication flow, acceptance and effectiveness of prevention programs when adequately implemented.

Study limitations

Several challenges will have to be overcome in this study. Firstly, the inclusion of 386 vigorous participants aged over 80 will be time-consuming for each participating APN and GP. However, for enrolment and screening, we will rely mainly on the patients’ list already compiled by the APN. GPs in the region have already been informed about the study and the protocol design. Moreover, our seven APN centers are already integrated into the geriatric care network. In addition, we believe that the possibility of following an individual tailored physical activity program for each participant will increase the motivation of both GPs and patients towards the protocol. In total, recruitment feasibility is supported by the strong regional APN-GP network, and attrition will be managed using multiple imputation methods to ensure robustness of the analyses.

Secondly, this study will also include a significant number of outcome measures that could compromise the willingness of the participants to continue the study. However, participants will be closely monitored with regular phone calls every two months and outcome measures will mainly be recorded during the CGA performed at 12 months. All CGAs will always be accompanied by tailored recommendations related to an overall healthcare plan, which will most likely increase the participants’ attendance at this crucial assessment, because it will be presented – outside the protocol – as essentially beneficial to the patients included.

Thirdly, for ethical reasons, the study design includes proposing free physical activity to each patient. However, the number of free physical activity sessions (n = 14) is lower than the minimum number of 24–36 sessions over 12 weeks recommended in the World guidelines for falls prevention and management [9]. This difference is due to feasibility reasons. Nevertheless, the ICFSR consensus guidelines [35] suggest a linear effect of exercise on falls and health outcomes, suggesting that 14 sessions should still be beneficial and ethically acceptable. Moreover, the aim of this study is not to assess the impact of physical activity on falls, but rather the role of APN in a real-life situation.

Fourthly, this open-label study design may induce performance bias as well as Hawthorne effect. However, in concordance with Godwin and colleagues [36], we adopted a conservative stance and decided to maximize external validity of the study. In addition, the second CGA at M12 will be performed by a research nurse, blinded of the group allocation.

Lastly, the retrospective collection of the number of falls will be subject to memory or reporting biases. However, we anticipate that a two-month interval between calls will help to mitigate these biases, especially as the patient sample is intentionally chosen to have a low prevalence of neurocognitive disorders. In addition, our design follows the 2022 World Guidelines for Falls Prevention and Management which recommend standardized retrospective question during structured follow-ups [9]. Cognitive screening tests will also be performed during the first CGA and corrective measures will be implemented if memory impairments are detected.

Dissemination plan and perspectives

The study results will be shared with various groups, such as the scientific community, study participants, patient groups, the general public, industry professionals, regulatory agencies, and policymakers. Communication methods will include among others publishing scientific articles, presenting the results at conferences, issuing press releases, conducting interviews, using social media and organizing meetings.

Updates and information will be regularly posted on the regional healthcare agency and Nantes University Hospital websites. In addition, the data collected in the study will be accessible for future analyzes, enabling researchers worldwide to better understand falls and frailty in a vigorous very old population.

Abbreviations

APN

Advanced practice nurses

CGA

Comprehensive geriatric assessment

GP

General practitioner

ENT

Ear, nose and throat

CFS

Clinical frailty scale

ICOPE

Integrated Care for Older People

TUG

Timed up and go test

SPPB

Short physical performance battery

MMSE

Mini mental state examination

FAB

Frontal assessment battery

GDS

Geriatric depression scale

BMI

Body mass index

MNA

Mini nutritional assessment

CUA

Cost-utility analysis

QALY

Quality-adjusted life year

SAE

Serious adverse events

MAR

Missing at random

ICER

Incremental cost-effectiveness ratio

SUR

Seemingly unrelated bootstrap

Authors’ contributions

All authors contributed to the study conceptualization and design. JH is responsible for drafting the manuscript. LD is the coordinating investigator and responsible for data collection. CRa, CRe and SC are responsible for participants’ enrolment. TD is responsible for the physical activity program. PC is responsible for data management and statistical analyzes. SM is responsible for the ancillary study of the intervention implementation. All authors participated in and supervised the study design and implementation. All authors reviewed and edited the manuscript and approved the final version. All authors are part of the steering committee.

Funding

The research funding is provided by the own funds of the sponsor and by a grant obtained following the selection of the APN-FIT project (“PREVIPAGE” in French) as part of the 2022 call for proposals by AXA Life Insurance (“Assurances VIE Mutuelle”). This funding agency has conducted an independent external peer review of the protocol as part of the funding approval process, as detailed in supplementary data (funding approval declaration and composition of the scientific committee). The funders played no role in the study design, the data collection and analysis, the decision to publish or the preparation of the manuscript.

Data availability

Only the (co-)investigators will have access to the final pseudonymized data set. A minimum data set allowing interpreting, reproducing and refining the results will be available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This protocol was approved and peer-reviewed by the Comité de Protection des Personnes Nord-Ouest IV, as required by the French law. It guarantees its ethical standards, as stated in the Declaration of Helsinki (7th revision, October 2013), and the research methodology. Amendments to the protocol will be possible and will be submitted to the relevant CPP for approval. All participants will sign an informed consent after a few days of reflection and may withdraw from the study at any time.

This study protocol followed the SPIRIT guidelines as detailed in the SPIRT checklist in supplementary data.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.