Behavioural digital biomarkers enable real-time monitoring of patient-reported outcomes: a substudy of the multicenter, prospective observational SafeHeart study

INTRODUCTION

Patient-reported outcome measures (PROMs) serve multiple purposes, including shared decision-making and patient communication, treatment monitoring and health-technology assessment. Patient monitoring using PROMs is constrained by recall and non-response bias, respondent burden and missing data. We evaluated the potential of behavioural digital biomarkers obtained from a wearable accelerometer to achieve personalised predictions of PROMs.

METHODS

Data from the multicenter, prospective SafeHeart study conducted at Amsterdam University Medical Center in the Netherlands and Copenhagen University Hospital, Rigshospitalet in Copenhagen, Denmark, was used. The study enrolled patients with an implantable cardioverter defibrillator (ICD) between May 2021 and September 2022 who then wore wearable devices with raw acceleration output to capture digital biomarkers reflecting physical behaviour. To collect PROMs, patients received the KCCQ and EQ5D-5 L questionnaire at two instances; baseline and after 6 months. Multivariable Tobit regression models were used to explore associations between digital biomarkers and PROMs, specifically whether digital biomarkers could enable PROM prediction.

RESULTS

The study population consisted of 303 patients (mean age 62.9 ± 10.9 years, 81.2% male). Digital biomarkers showed significant correlations to patient-reported physical and social limitations, severity and frequency of symptoms and quality of life. Prospective validation of the Tobit models indicated moderate correlations between the observed and predicted scores for KCCQ (concordance correlation coefficient (CCC) = 0.49, mean difference: 1.07 points) and EQ5D-5 L (CCC = 0.38, mean difference 0.02 points).

CONCLUSION

Wearable digital biomarkers correlate with PROMs, and may be leveraged for real-time prediction. These findings hold promise for monitoring of PROMs through wearable accelerometers.

Accidental diagnosis of bradyarrhythmia in patients monitored for atrial fibrillation

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): The study was supported by The Innovation Fund Denmark [12-135225], The Research Foundation for the Capital Region of Denmark [no grant number], The Danish Heart Foundation [11-04-R83-A3363-22625], Aalborg University Talent Management Programme [no grant number], Arvid Nilssons Fond [no grant number], Skibsreder Per Henriksen, R. og Hustrus Fond [no grant number], Medtronic [no grant number], and the AFFECT-EU consortium which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 847770.

Background

The interest in heart rhythm monitoring and technologies to detect arrhythmia is increasing. The prevalence and prognostic significance of subclinical bradyarrhythmias is unknown.

Objectives

To assess the accidental diagnosis of bradyarrhythmia and its subsequent treatment and prognostic impact in persons screened for atrial fibrillation compared to unscreened persons.

Methods

We utilized a randomized trial of ≥70-year-olds with cardiovascular risk factors recruited outside the hospital setting to receive implantable loop recorder screening for atrial fibrillation (ILR group) vs. usual care (Control group). Time-to-event analyses were performed for bradyarrhythmia, pacemaker implantation, syncope, and sudden cardiovascular death.

Results

A total of 6004 participants were randomized (mean age 75 years, 47% women, 91% with hypertension, 20% with prior syncope), 4503 to Control and 1501 to ILR. The median follow-up period was 64.5 [59.3, 69.8] months. A total of 675 deaths occurred with an overall rate of 2.16 (2.00-2.33) per 100 person-years, and 67 sudden cardiovascular deaths occurred with a rate of 0.21 (0.15-0.28) for the Control group and 0.23 (0.14-0.37) for the ILR group (hazard ratio (HR) 1.11 (0.64-1.90), p=0.71)).

The overall rate of incident bradyarrhythmia was 1.63 (1.49-1.79) per 100 person-years, and bradyarrhythmia was diagnosed in 172 (3.82%) and 312 (20.8%) participants in the Control and ILR group, respectively (HR 6.21 (5.15-7.48), p<0.0001) (Figure 1). The most common bradyarrhythmia was sinus node dysfunction (SND) which was diagnosed in 68 participants in the Control group (1.51%) and 214 in the ILR group (14.26%). In the Control group, 57.35% of diagnoses of sinus node dysfunction resulted in pacemaker implantation, compared to 12.15% in the ILR group where the majority was treated conservatively (Figure 2). The second-most common type of bradyarrhythmia was high-grade atrioventricular block (AVB) which was diagnosed in 86 participants in the Control group (1.91%) and 54 in the ILR group (3.60%). In both groups, the majority of high-grade AVB was treated with pacemaker, although 29.63% in the ILR group were treated conservatively. Risk factors for bradyarrhythmia included higher age, male sex, and prior syncope.

Overall, a pacemaker was implanted in 132 (2.93%) and 66 (4.40%) participants (HR 1.53 (1.14-2.06), p<0.0001), syncope occurred in 120 (2.66%) and 33 (2.20%) participants (HR 0.83 (0.56-1.22), p=0.34), and sudden cardiovascular death occurred in 49 (1.09%) and 18 (1.20%) participants (HR 1.11 (0.64-1.90), p=0.71) in the Control and ILR group, respectively.

Conclusions

Bradyarrhythmias are highly common in ≥70-year-olds with cardiovascular risk factors. Compared to Control, ILR monitoring led to a six-fold increase in diagnosis of bradyarrhythmia and a significant increase in pacemaker implantations, but no change in the risk of syncope or sudden death.

Adherence to wearables in implantable cardioverter-defibrillator patients: Preliminary results from the prospective, multicenter SafeHeart-study

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Horizon2020

Introduction

Wearable devices are gaining interest in the clinical assessment of physical behavior as a marker of disease severity. With the increased use, patient willingness and adherence will be increasingly important. As part of the SafeHeart study, examining the potential of physical behavior as an identifier of clinical deterioration in patients with an implantable cardioverter defibrillator (ICD), we present preliminary results on adherence to a wrist-worn wearable used for physical behavior assessment.

Purpose

Define the willingness to participate and long-term adherence to wearables in an ICD population.

Methods

This is a preliminary analysis of the ongoing multicenter, prospective, observational SafeHeart study. SafeHeart is aimed to construct a personalized prediction engine for ICD therapy using wearable-assessed physical behavior, remote ICD monitoring, electronic health records, and patient-reported data. The study will enroll 400 participants with an ICD with or without cardiac resynchronization therapy (CRT-D). In this preliminary analysis, wearable data was analyzed for the first 50 participants, where inclusion required a minimum of 1 month of follow up data. No data from the wearables were provided to the participants. The wrist-worn wearables were used continuously (day and night) for up to 12 months of follow-up. Adherence to the wearable was measured through patient-reported (subjective) adherence and wearable-measured (objective) adherence. Data were extracted from the wearables and non-wear time was detected via open source algorithms. A valid day was set to 22 hours of available wear time with 24-hour periods assessed from 3pm to 3pm for sleep metric capture. The willingness to participate and dropout rates were calculated for the same first 50 patients of the study.

Results

A total of 50 ICD participants were included in this study. The mean age was 65.1 years, 82 % male, with a mean follow up of 7 weeks, generating 326 patient weeks of data. Regarding patient-reported adherence, participants reported 81.4% full adherence and 18.6 % of participants reported very brief non-wear due to e.g. sauna or surgery. Of those reporting non-wear, 62.5% described one episode only of non-wear lasting 15-75 minutes. Regarding objectively measured adherence from wearable data, full adherence was shown in 91.7% of days. The mean number of valid days per participant was 41.3. Recruitment rates showed a willingness to participate of 50% (50/100) out of eligible subjects invited. No participants were lost to follow

Conclusion

Results show high adherence and reasonable willingness to participate without wearable adherence dropping over time. Comparison of objectively measured and patient-reported adherence showed similar values.

Accelerometry-assessed physical behaviour and the association with clinical outcomes in implantable cardioverter-defibrillator recipients: a systematic review

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Eurostars

Introduction

Patients at a high risk of sudden cardiac death (SCD) benefit from an implantable cardioverter defibrillator (ICD). However, they remain at a high risk of (inappropriate) shocks, heart failure, mortality and psychological distress. Consumer-level wearable accelerometry as method for recording physical behaviour (PB) has gained popularity over the past years, but so far the clinical potential is largely underinvestigated. The identification of patterns in PB and the association with clinical outcomes may provide a means to improve ICD therapy.

Purpose

This review addresses the evidence concerning PB in ICD patients and aims to characterise PB patterns associated with clinical outcomes.

Methods

A systematic review of studies focussing on accelerometer-assessed PB in patients older than 18 years equipped with an ICD, or patients at a high risk of SCD (e.g. advanced heart failure) was performed. PB could be assessed using a wearable accelerometer or an embedded accelerometer in the ICD (i.e. device-measured physical activity (D-PA)). Papers presenting quantitative data in English language peer reviewed journals published between January 2000 and September 2020 were identified via the OVID MEDLINE and OVID EMBASE databases. A study protocol describing study selection, data charting and summarisation of results was developed apriori. Study selection was conducted by two independent reviewers and a third reviewer in case of disagreement.

Results

A total of 4219 studies were identified, of which 51 were deemed appropriate for this review. Of these studies, 29 examined D-PA (n = 169.742 patients), 19 examined wearable accelerometery (n = 1.601) and 3 validated wearable accelerometry against D-PA (n = 106). The main findings were that (i) a low level of physical activity (PA) after implantation of the ICD and (ii) a decline in physical activity were both associated with an increased risk of ICD shocks, hospitalization and mortality. Second, PB was affected by cardiac factors (e.g. onset of atrial arrhythmias, ICD shocks) and non-cardiac factors (e.g. seasonal differences, pandemic lockdown). Third, PB was related to left ventricular ejection fraction, physical and cognitive function and quality of life. The evidence regarding wearable accelerometry compared to D-PA was scarce and heterogeneous.

Conclusion

This review demonstrated the potential of PB as an identifier of clinical deterioration in an ICD population. Accelerometer-assessed PB data could improve early warning systems and facilitate preventive and pro-active strategies, especially considering the nature of PB as modifiable risk factor. We suggest two directions for future research: (i) prospective collection of wearable accelerometry data in an ICD population to identify the most clinically relevant behavioural metrics (ii) investigation of preventive measures that can be undertaken once changes in PB are observed. Abstract Figure. Accelerometry-derived physical behaviour