eISSN: 2300-6722
ISSN: 1899-1874
Medical Studies/Studia Medyczne
Current issue Archive About the journal Abstracting and indexing Subscription Contact Instructions for authors
3/2017
 
Share:
Share:
more
 
 
Original paper

The smartphone as an instrument for blood pressure measurement

Mariusz Pawłowski, Jakub S. Gąsior, Ewelina Dziedzic, Tomasz Klepko, Marek Dąbrowski

Medical Studies/Studia Medyczne 2017; 33 (3): 222–226
Article file
Get citation
ENW
EndNote
BIB
JabRef, Mendeley
RIS
Papers, Reference Manager, RefWorks, Zotero
AMA
APA
Chicago
Harvard
MLA
Vancouver
 
 

Introduction

Smartphones are transforming culture, social life, technology, and other diverse aspects of modern society [1]. Medicine is also experiencing the growing impact of the mobile phone industry [2–5]. Use of smartphones and specially design medical applications (apps) could have potential benefits for healthcare [4, 6]. The smartphone could be an ideal monitoring tool for physicians because patients could be tested anywhere at any time and in any circumstances [7].
In daily clinical practice the authors of this report were asked by patients with hypertension about the possibility of using a smartphone app to perform blood pressure (BP) measurements in the home environment. To date, the authors of this report did not find any studies that could provide an answer to such questions.
Research in this field is important inter alia because of the fact that in clinical medicine BP measurements are considered to be one of the most important [8]. Monitoring of BP in the home environment has potential benefit in the management of hypertension [9], which affects nearly one billion people or ~26% of the adult population of the world [10]. The number of adults suffering from hypertension is predicted to increase, so prevention, detection, treatment, and control of this issue should receive high priority [10]. Hypertension among patients from the United States (U.S.) is listed as a primary or contributing cause in ~15% of the 2.4 million deaths that occurred in 2009 [11]. Annual costs directly attributable to hypertension are projected to increase to $130.4 billion in 2030 [12]. It is predicted that the use of home BP monitoring for hypertension diagnosis would result in a saving of billions dollars in hypertension-related medical costs [13]. That is why, among other aspects, self BP monitoring has been recommended by experts and international guidelines as an adjunct to office BP monitoring for the management of hypertension [14]. Screening for high blood pressure was also recommended in adults by the U.S. Preventive Services Task Force (grade A recommendation) [15].

Aim of the research

That is why the aim of this study was to evaluate the feasibility of blood pressure measurement done by smartphone application (Real Blood Pressure Calc® by PurePush) in the group of patients with hypertension compared with testing done by a trained health care provider according to American Heart Association (AHA) recommendations [8].

Material and methods

The study included 50 patients hospitalised in a cardiology department. All participants had the diagnosis of hypertension and were under antihypertensive-medication control. The study protocol was approved by the Local Ethics Committee. Traditional BP measurement using a sphygmomanometer and the Korotkoff sound technique was done by a trained health care provider according to AHA guidelines as a standard clinical procedure [8].
Before and after the traditional procedure, authors tested BP using the Real Blood Pressure Calc by PurePush smartphone application. The patient’s position was based on the AHA BP measurement guidelines [8]. The procedure of phone BP testing was based on the guidelines provided by the provider of the application, and included: pressing the smartphone camera lens gently with the index finger of the right hand, and pressing the index finger of the left hand on the phone screen in a marked area. After 10 s of measurement the results were read. The patients were blinded to the results obtained by the healthcare provider until they had tested their BP by themselves.

Procedures

The BP measurement was performed in the following order:
– BP measurement using smartphone by a trained healthcare provider;
– BP measurement using a sphygmomanometer by a trained healthcare provider;
– BP measurement using a smartphone by the patient him/herself.
Patients rested for 10 min while the procedure was explained to them.
Loud and clear instructions were given on how the test should be conducted and what the patient should do. These instructions included the following information: hold still, cover the camera lens with your fingertip, press gently on the camera.

Statistical analysis

Normality was assessed using the Shapiro-Wilks test. Student’s t test was used when the data were normally distributed and the Mann-Whitney U test was used for other comparisons. A significance level of p < 0.05 was chosen for overall effects. We performed the following comparisons:
– results derived from the smartphone app versus results obtained using a sphygmomanometer (both measurements were conducted by a trained healthcare provider);
– results derived from the smartphone app, conducted by trained healthcare provider, versus results from the smartphone app performed by the patient him/herself.
The total number of results that differed from the measurement performed by the specialist by more than 5 mm Hg, and by 10% or more, was additionally recorded.

Results

Mean results for systolic (SBP) and diastolic (DBP) blood pressure measurement are presented in Table 1.
The authors evaluated the difference between the results in a different condition of measurement. The results were divided according to the context of measurement. Summary of statistical significance (p-value) for both systolic and diastolic BP in all conditions are show in Table 2.
The total number of results that differed from the measurement performed by the specialist by more than 5 mm Hg, and by 10% or more, was counted. A summary of this analysis is shown in Table 3.

Discussion

According to its potential advantages and the mean results presented in Table 1, smartphones could be a useful tool for BP monitoring. The mean results of both systolic and diastolic BP did not differ significantly between measurements done by healthcare provider in the traditional way and by smartphone app (Table 2). It is known that screening of BP in the population for detection of hypertension early, and initiation of treatment before the onset of target organ damage is highly cost effective [16, 17]. The rising popularity of smartphones could be helpful in BP screening in the population. However, further data analysis showed a poor level of accuracy in BP testing done by smartphone application in conditions other than those measured by a healthcare provider (Table 2). Such results indicate that at present screening of BP in the population using smartphones should not be done. Similarly, no significant agreement was observed in BP assessment done by a healthcare provider using a smartphone versus results from a smartphone used by the patient him/herself. More data (Table 3) demonstrate that the results of BP testing done by smartphone can be considered as incidental. The total amount of results deviating more than 5 mm Hg and by 10% or more from the measurement performed by the specialist is dumbfounding.
Exact measurement of BP is of paramount importance [16]. Underrating true blood pressure by 5 mm Hg would mislabel millions of individuals as having pre hypertension when true hypertension is actually present. For example, underestimation of the DBP by 5 mm Hg could result in more than 60% of hypertensive individuals being denied potentially lifesaving treatment, while the number of persons diagnosed with hypertension would more than double if SBP were over estimated by 5 mm Hg [16, 18–21]. Data presented in Table 3 indicate that regardless of the type of comparison there are a number of results that differ from the Korotkoff sound technique results in a range greater than 5 mm Hg. This result indicates that there is a chance of getting a result similar to the professional measurement; however, the differences observed in many cases (Table 3), in the authors’ opinion, do not allow the results obtained by smartphone to qualify as an acceptable outcome.
The producer of the tested application states that the app calculates blood pressure with approximately ±10% accuracy. Our results (Table 3) indicate that not all results are within this range. Measurements done both by healthcare provider and the patient him/herself demonstrate a large number (36% to 86%) of results that were not within the range that the producer of the application stated.
Guidelines and experts are unanimous about the statement that only devices that have passed adequate validation tests, referring to standard protocols, should be used and recommended [8]. The tested app calculates BP on the basis of brightness of the skin over time captured by a camera lens. The algorithms used for the calculation of BP measurement have not been published by the provider of the application, making it impossible to understand the basis of the BP results, or to have a point of discussion about the essence of the idea of the app author, and about the results of any testing. There is also no publication on this topic so far. We searched the Medline database using the keywords: blood pressure, phone, smartphone, and application, and no research referring to this topic was identified. The lack of reliable information and inconclusive results of this study give the authors concern about the many random comments of appreciation found on the application webpage (examples: Glenn Felton Jr: “Excellent I can now track with accuracy…”, Krishna Kumar Tiwari: “Nice & useful. Works great”, Rolando Hernandez: “Awesome. Works”). The popularity of medical designed apps is still growing [3, 4, 6]. “Real Blood Pressure Calc® by PurePush” used in the present study has been downloaded and installed from the manufacturer’s worldwide webpage somewhere in the range 1,000,000 to 5,000,000 times. The authors of this report think that inaccurate results and misleading information about the state of patients’ health can have adverse effect on patients’ health condition. There are a lot of potential threats resulting from the clearly false or misleading results generated from the tested application. It is generally known that BP is a predictor of cardiovascular events [22, 23]. Misdiagnosis of hypertension, beyond the patient’s mental burden, may lead to unnecessary initiation of a medical visit and treatment. Showing significant prognostic value [23], monitoring of BP is recommended by the American Heart Association to determine whether treatments are working properly [8]. Correct BP observed during subsequent home testing can be regarded as an expression of the effectiveness of treatment, confirming its validity. In turn, unrecognised hypertension can lead to discontinuation of proper treatment and consequently to complications in the cardiovascular system [24].
According to the results of this report and the well-established position of self-monitoring of BP and its potential for prevention of white collar and masked hypertension [25], the authors conclude that during routine visits, patients should be asked about the source of any BP results brought into the medical doctor’s office. Moreover, patients and physicians should be warned and be aware of possible inaccurate measures from smartphone apps for home BP measurement in hypertension management or screening of blood pressure. The authors of this report also think that regulation and guidance for health-related apps are necessary if the use of mobile technology for assessing health condition is to be safe. Summing up, according to the presented results, the authors of this publication think that smartphone apps should not be used for the control of blood pressure in the group of patients with hypertension and for screening of blood pressure in the general population as yet. Future research should be done in the field of testing the validity of other unverified blood pressure smartphone applications.

Conclusions

The smartphone application tested in this study should not be used for blood pressure monitoring as yet due to the high range of measurement error observed in this study.

Conflicts of interest

The authors declare no conflict of interest.

References

1. Pickering TG, Hall JE, Appel LJ, Falkner BE, Graves J, Hill MN, Jones DW, Kurtz T, Sheps SG, Roccella EJ. Recommendations for blood pressure measurement in humans and experimental animals: part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research. Circulation 2005; 111: 697-716.
2. U.S. Preventive Services Task Force. Screening for high blood pressure: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med 2007; 147: 783-6.
3. Pickering TG. Principles and techniques of blood pressure measurement. Cardiol Clin 2002; 20: 207-23.
4. Go AS, Bauman MA, Coleman King SM, Fonarow GC, Lawrence W, Williams KA, Sanchez E; American Heart Association; American College of Cardiology; Centers for Disease Control and Prevention. An effective approach to high blood pressure control: a science advisory from the American Heart Association, the American College of Cardiology, and the Centers for Disease Control and Prevention. Hypertension 2014; 63: 878-85.
5. Agarwal R, Bills JE, Hecht TJ, Light RP. Role of home blood pressure monitoring in overcoming therapeutic inertia and improving hypertension control: a systematic review and meta-analysis. Hypertension 2011; 57: 29-38.
6. Funahashi J, Ohkubo T, Fukunaga H, Kikuya M, Takada N, Asayama K, Metoki H, Obara T, Inoue R, Hashimoto J, Totsune K, Kobayashi M, Imai Y. The economic impact of the introduction of home blood pressure measurement for the diagnosis and treatment of hypertension. Blood Press Monit 2006; 11: 257-67.
7. Niiranen TJ, Hänninen MR, Johansson J, Reunanen A, Jula AM. Home-measured blood pressure is a stronger predictor of cardiovascular risk than office blood pressure: the Finn-Home study. Hypertension 2010; 55: 1346-51.
8. Ward AM, Takahashi O, Stevens R, Heneghan C. Home measurement of blood pressure and cardiovascular disease: systematic review and meta-analysis of prospective studies. J Hypertens 2012; 30: 449-56.
9. Pickering TG, White WB; American Society of Hypertension Writing Group. When and how to use self (home) and ambulatory blood pressure monitoring. J Am Soc Hypertens 2008; 4: 119-24.
10. McManus RJ, Glasziou P, Hayen A, Mant J, Padfield P, Potter J, Bray EP, Mant D. Blood pressure self monitoring: questions and answers from a national conference. BMJ 2008; 337: a2732.
11. Ozdalga E, Ozdalga A, Ahuja N. The smartphone in medicine: a review of current and potential use among physicians and students. J Med Internet Res 2012; 14: e128.
12. Buijink AW, Visser BJ, Marshall L. Medical apps for smartphones: lack of evidence undermines quality and safety. Evid Based Med 2013; 18: 90-2.
13. Gupta G. Are medical Apps the future of medicine? Med J Armed Forces India 2013; 69: 105-6.
14. Heidenreich PA, Trogdon JG, Khavjou OA, Butler J, Dracup K, Ezekowitz MD, Finkelstein EA, Hong Y, Johnston SC, Khera A, Lloyd-Jones DM, Nelson SA, Nichol G, Orenstein D, Wilson PW, Woo YJ; American Heart Association Advocacy Coordinating Committee; Stroke Council; Council on Cardiovascular Radiology and Intervention; Council on Clinical Cardiology; Council on Epidemiology and Prevention; Council on Arteriosclerosis; Thrombosis and Vascular Biology; Council on Cardiopulmonary; Critical Care; Perioperative and Resuscitation; Council on Cardiovascular Nursing; Council on the Kidney in Cardiovascular Disease; Council on Cardiovascular Surgery and Anesthesia, and Interdisciplinary Council on Quality of Care and Outcomes Research. Forecasting the future of cardiovascular disease in the united states: a policy statement from the American Heart Association. Circulation 2011; 123: 933-44.
15. Sarwar M, Tariq RS. Impact of Smartphone’s on Society. Eur J Sci Res 2013; 98: 216-26.
16. Charani E, Castro-Sánchez E, Moore LS, Holmes A. Do smartphone applications in healthcare require a governance and legal framework? It depends on the application! BMC Med 2014; 14: 12-29.
17. Mosa AS, Yoo I, Sheets L. A systematic review of healthcare applications for smartphones. BMC Med Inform Decis Mak 2012; 12: 67.
18. Pelegris P, Banitsas K, Orbach T, Marias K. A novel method to detect heart beat rate using a mobile phone. Conf Proc IEEE Eng Med Biol Soc 2010; 54: 88-91.
19. Cappuccio FP, Kerry SM, Forbes L, Donald A. Blood pressure control by home monitoring: meta-analysis of randomised trials. Br Med J 2004; 329: 145.
20. Wackel P, Beerman L, West L, Arora G. Tachycardia detection using smartphone applications in pediatric patients. J Pediatr 2014; 164: 1133-5.
21. Hanning CD, Alexander-Williams JM. Pulse oximetry: a practical review. BMJ 1995; 311: 367-70.
22. Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, He J. Global burden of hypertension: analysis of worldwide data. Lancet 2005; 365: 217-23.
23. McAlister FA, Straus SE. Evidence based treatment of hypertension. Measurement of blood pressure: an evidence based review. BMJ 2001; 322: 908-11.
24. Littenberg B. A practice guideline revisited: screening for hypertension. Ann Intern Med 1995; 122: 937-9.
25. Campbell NR, McKay DW. Accurate blood pressure measurement: why does it matter? Can Med Assoc J 1999; 161: 277-8.

Address for correspondence:

Mariusz Pawłowski MD
Cardiology Clinic of Physiotherapy Division
2nd Faculty of Medicine
Medical University of Warsaw
ul. Cegłowska 80, 01-809 Warsaw, Poland
Phone: +48 796 062 122
E-mail: pawlowskimariusz@o2.pl
Copyright: © 2017 Jan Kochanowski University in Kielce This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) License (http://creativecommons.org/licenses/by-nc-sa/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material, provided the original work is properly cited and states its license.
Quick links
© 2017 Termedia Sp. z o.o. All rights reserved.
Developed by Bentus.
PayU - płatności internetowe