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Advances in digital technologies have allowed remote monitoring and digital alerting systems to gain popularity. Despite this, limited evidence exists to substantiate claims that digital
alerting can improve clinical outcomes. The aim of this study was to appraise the evidence on the clinical outcomes of digital alerting systems in remote monitoring through a systematic
review and meta-analysis. A systematic literature search, with no language restrictions, was performed to identify studies evaluating healthcare outcomes of digital sensor alerting systems
used in remote monitoring across all (medical and surgical) cohorts. The primary outcome was hospitalisation; secondary outcomes included hospital length of stay (LOS), mortality, emergency
department and outpatient visits. Standard, pooled hazard ratio and proportion of means meta-analyses were performed. A total of 33 studies met the eligibility criteria; of which, 23 allowed
for a meta-analysis. A 9.6% mean decrease in hospitalisation favouring digital alerting systems from a pooled random effects analysis was noted. However, pooled weighted mean differences
and hazard ratios did not reproduce this finding. Digital alerting reduced hospital LOS by a mean difference of 1.043 days. A 3% mean decrease in all-cause mortality from digital alerting
systems was noted. There was no benefit of digital alerting with respect to emergency department or outpatient visits. Digital alerts can considerably reduce hospitalisation and length of
stay for certain cohorts in remote monitoring. Further research is required to confirm these findings and trial different alerting protocols to understand optimal alerting to guide future
widespread implementation.
With our ever-ageing population, a result of significant improvements in healthcare delivery, medicine, personal & environmental hygiene, a greater burden is placed on our primary and
secondary care healthcare facilities1. The rising costs of healthcare delivery require novel strategies to improve healthcare service provision2, particularly one that proves to be
cost-effective and is widely accepted by citizens.
Telemedicine, a concept since the 1970s, has evolved to be synonymous with terms such as digital health, e-health, m-health, wireless health, and, remote monitoring, among others. Indeed,
over 100 unique definitions have been uncovered for ‘telemedicine’, a variation, which is likely to be attributed to the progression of these technologies3,4. Remote monitoring allows people
to continue living at home rather than in expensive hospital facilities through the use of non-invasive digital technologies (such as wearable sensors) to collect health data, support
health provider assessment and clinical decision making5. Several randomised trials have demonstrated the potential for remote monitoring in reducing in-hospital visits, time required for
patient follow-up, and hospital costs in individuals fitted with cardiovascular implantable electronic devices6,7,8.
Vital signs including, heart rate (HR), respiratory rate (RR), blood pressure (BP), temperature, and oxygen saturations, are considered a basic component of clinical care and an aide in
detecting clinical deterioration; changes in these parameters may occur several hours prior to an adverse event9,10. With wearable sensors being light-weight, small, and discrete they can be
powerful diagnostic tools for continuously monitoring important physiological signs and offer a non-invasive, unobtrusive opportunity for sensor alerting systems to remotely monitor
patients, driving the potential to improve timeliness of care and health-related outcomes11.
Feedback loops and alerting mechanisms allow for appropriate action following recognition of clinical deterioration. Current alerting mechanisms for remote monitoring include alert
transmission to a mobile device; automated emails generated to a healthcare professional; video consultation; interactive voice responses; or web-based consultations12. The feedback loops
can be relayed to nurses, pharmacists, physicians, counsellors, and physicians but also to patients13. Earlier recognition of deterioration, through alerting mechanisms, has potential to
improve clinical outcomes, such as hospitalisation, length of stay, mortality, and subsequent hospital visits, through earlier detection but has been inadequately studied.
A recent systematic review reported outcomes for remote monitoring undertaken in individuals in the community with chronic diseases (e.g., hypertension, obesity, and heart failure), but many
of the included studies were of low quality and underpowered; the meta-analyses were on obesity related intervention outcomes (body mass index, weight, waist circumference, body fat
percentage, systolic blood pressure, and diastolic blood pressure), consisting of few studies13. Additionally, the evaluation of feedback loops and alerting mechanisms following recognition
of abnormal parameters was not the main focus of this study, a pivotal phase where intervention could influence clinical outcomes. With the search performed in 2006, and the rapid evolution
of such a field, an updated systematic review aimed at digital alerting mechanisms is warranted, with the inclusion of wider medical and surgical cohorts for generalisability. The aim of
this systematic review is to identify studies evaluating digital alerting systems used in remote monitoring and describe the associated clinical outcomes.
A total of 2417 citations were retrieved through literature searches. An additional two articles were found from bibliography cross-referencing. Full-text review was performed for 128
articles with 33 meeting the inclusion criteria for analysis, of which, 21 were randomised controlled trials with the remaining prospective or retrospective studies. Of the 33 included
studies, 23 allowed for meta-analysis. The characteristics of included studies is shown in Table 1. A PRISMA flow diagram can be seen in Fig. 1.
Six studies demonstrated a mean decrease in hospitalisation/inpatient admissions of 9.6% (95% CI 4.9–14.3%, I2 = 96.4%, Fig. 2) favouring digital alerting systems from a pooled random
effects analysis. However, pooled WMD reported no change in hospitalisation from six studies (WMD 0.061; 95% CI −0.197–0.318, I2 = 78%)14,15,16,17,18,19. Pooled HRs for all-cause
hospitalisation similarly demonstrated no significant difference (HR 0.916; 95% CI 0.781–1.074, I2 = 0%)20,21.
Forest plot of studies reporting hospitalisation and inpatient admissions.
Six additional studies, reporting on cardiovascular related hospitalisation, revealed no significant relationship with digital alerting (mean decrease 10.1%; 95% CI −24.9–4.7%, I2 = 95.6%
and pooled HRs 0.907; 95% CI 0.757–1.088, I2 = 2.4%)20,22,23,24,25
A total of 16 papers were included; pooled random effects analysis demonstrated a 3% mean decrease in all-cause mortality from digital alerting systems (95% CI 2–3%, Fig. 3) from 12 studies;
there was high heterogeneity with this analysis (I2 = 94.4%). However, pooled HRs of five studies reported no change in all-cause mortality (HR 0.89; 95% CI 0.79–1.01, I2 =
30.3%)20,21,25,26,27.
A sub-group cardiovascular cohort pooled random effect analysis failed to demonstrate a relationship between cardiovascular mortality and digital alerting (mean decrease 0.9%, 95% CI
−0.6–2.4%, I2 = 25.7%)20,24.
Ten studies were included; digital alerting reduced hospital LOS by a mean difference of 1.043 days (95% CI 0.028–2.058 days, p