SAMJ publication: Home monitoring using a pulse oximeter linked to 48% lower likelihood of death in high-risk scheme members who have COVID-19.
Shirley Collie (Chief Analytics Actuary at Discovery Health), Jared Champion (Senior Actuary at Discovery Health), Tommy Chen (Actuary at Discovery Health) and Michael Cohen (Actuarial Analyst at Discovery Health)
Between 2 March 2020 and 31 October 2020, Discovery Health investigated the extent to which the use of a pulse oximeter could reduce the risk of hospital admission and mortality in high-risk medical scheme members recovering at home from COVID-19.
Outcomes linked to a group of 38 645 high-risk COVID-positive scheme members were analysed. Within this group, 8 113 individuals received a pulse oximeter from Discovery Health during the period of their home-based recovery. Remaining individuals who were eligible to receive a pulse oximeter but were not sent one, were either already admitted to hospital at the point at which their positive COVID-19 test result came through, or they were uncontactable.
- Individuals included in the study were all members of medical schemes administered by Discovery Health
- High risk individuals within the member base were classified by their demographic information and underlying conditions
- Underlying conditions included living with diabetes mellitus, cardiovascular conditions, chronic lung disease, chronic liver disease or other immunocompromising conditions.
Why are pulse oximeters so relevant in the context of at-home recovery from COVID-19?
Pulse oximeters are small, cost-effective, user-friendly, fast-reading devices. They offer a means for an individual, especially those considered high-risk of severe COVID-19 illness, to monitor their blood oxygen levels, or blood oxygen saturation. This is read as a percentage - ideally between 90% and 100% in a healthy person. They also measure heart rate. Both readings are available when the device is placed on one's fingertip.
Pulse oximeters allow for early and remote detection of a condition called 'silent hypoxaemia', a condition observed in patients who develop COVID-19 pneumonia. The condition is characterised by low oxygen saturation levels (below 90%) in individuals who appear clinically well. Using a pulse oximeter offers a quick and simple way to regularly track oxygen saturation. They can then immediately detect any trend toward silent hypoxaemia for early medical intervention. Most often, high-risk medical scheme members who are recovering at home are monitored remotely by a primary care doctor who keeps track of their readings.
The use of a pulse oximeter could possibly reduce the lead time to escalation of treatment, hospital admissions, the requirement for intensive care and mechanical ventilation, and patient deaths.
Our findings in more detail
The 60-day COVID-19 mortality rate for the evaluated high-risk population was 1.35%:
- 0.68% for those who received a pulse oximeter
- 1.44% for those who did not receive a pulse oximeter.
After adjusting for age and comorbidity differences between the groups, pulse oximeter recipients showed a 48% lower mortality rate compared to high-risk scheme members who did not receive a pulse oximeter. The pulse oximeter recipient group included older scheme members and individuals who live with the top five comorbid conditions (hypertension, diabetes, ischaemic heart disease, asthma, and HIV), putting them at higher risk of worse outcomes when contracting COVID-19.
Number of deaths recorded - and lives saved
Overall, 49 scheme members who received pulse oximeters died. The mortality rate in this group was 0.68%. Applying the mortality rate seen in the group that did not make use of pulse oximeters (1.44%) to the group that did make use of them shows that there could have been 95 deaths in this group. This means the use of a pulse oximeter is estimated to have saved 46 lives.
Insights related to admission to hospital
Risk of admission to hospital, admission to ICU and the use of mechanical ventilation was not significantly different between pulse oximeter recipients and those who did not receive a pulse oximeter.
However, those who received pulse oximeters and were subsequently admitted to hospital presented with less severe disease than those who did not receive pulse oximeters.
- This data is based on C-reactive protein (CRP, a measure associated with inflammation) pathology results. The statistically significantly lower CRP results among scheme members who monitored their oxygen saturation using a pulse oximeter may explain the lower mortality rate in this group. (Note - almost all deaths occur after an admission).
- Please refer to the study in full, as published in the SAMJ.
A note of thanks
In addition to the acknowledgements listed in the SAMJ publication, Shirley Collie, Jared Champion, Tommy Chen and Michael Cohen, would like to thank our co-authors, Professor Guy Richards (Emeritus Professor of Critical Care, Faculty of Health Sciences, University of the Witwatersrand Johannesburg South Africa) and Professor Charles Feldman (Distinguished Professor of Pulmonology, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand) for their guidance, expertise and time spent in shaping the manuscript appropriately for publication.
We would also like to thank our colleague, Dr Noluthando Nematswerani (Head of the Discovery Health centre for Clinical Excellence), who not only helped craft the literature review, but also supported the significant time and energy required to make sure the analytics were of a peer-reviewed publishable standard.
Please contact us on MEDIA_RELATIONS_TEAM@discovery.co.za to request any updated data available since publication and any further context required.
All information shared on this page is based on perspectives gained from analysis of figures and trends emanating from Discovery Health's data pool. The analysis, which is conducted by Discovery Health's actuarial and data scientist team, aims to encourage industry dialogue. This content shared is for educational and informational purposes only.
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