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Smartphone-based 6-minute walking test while walking in the park: bringing physical fitness monitoring to the patient’s hands

Tijdschriftbijdrage - Tijdschriftartikel

In recent years, patient care has partially shifted from the hospital to the patients' homes. 1 This evolution is also seen in cardiac rehabilitation, in which a growing number of patients is participating in cardiac telereh-abilitation programmes. At present, a limiting factor in offering fully remote care is the need for assessing and reassessing the patient's physical fitness at predefined intervals in order to adjust the training programme. Currently, assessing physical fitness is done by either performing a cardiopulmonary exercise test (CPET), which assesses maximal exercise capacity, or a 6-min walking test (6 MWT), which assesses submaximal exercise capacity. 2 This study aimed to investigate a new tool that allows patients to self-test their submaximal exercise capacity in a flexible way by a smartphone-based random walk 6 MWT. This study is a subanalysis of a study that was previously published by our group. 3 In this paper, multiple algorithms were used for performing the 6 MWT, and the best algorithm was determined. This best algorithm is the algorithm that is used for this sub-analysis. The study demonstrated that an algorithm based on the Google Fit step count with the smartphone worn in a strap around the patient's arm performed the best when considering both accuracy and reliability. 3 Seventy-six patients were recruited after performing a standard CPET in the setting of a cardiac rehabilitation programme. All patients then performed two additional tests. In the first test patients performed a 6 MWT outdoors in a park along a flat, straight and fixed 30-meter path. The distance walked was measured by the researcher (as in a standardized 6 MWT). At the same time, the patient wore a smartphone recording the 6 MWT. In the second test, the free walk in the park 6 MWT (FWP-6 MWT), the same setup was applied, but patients were now instructed to walk freely in the park for 6 min. The primary outcome for this study was the correlation between the FWP-6 MWT and the peak oxygen consumption (VO 2); secondary outcomes included the correlation between the FWP-6 MWT and other CPET variables. The mean age was 65.7 ± 10.4 years; most participants were male (75%). Additional baseline characteristics can be found in Appendix. In our previous study it was already demonstrated that FWP-6 MWT is significantly correlated with standard 6 MWT distance (r = 0.929, P < 0.001). This subanalysis revealed a moderate correlation of FWP-6 MWT distance with peak VO 2 (r = 0.558, P < 0.001), VO 2 at ventilatory threshold 2 (r = 0.550, P < 0.001), and with peak power (r = 0.596, P < 0.001). There was no significant difference in the correlation between patients with low 6 MWT distance and higher 6 MWT distance. Multiple linear regression analysis showed that 58.1% of the variance in VO 2 max could be explained by using the free walk smartphone-registered 6 MWT distance, gender, presence of diabetes mellitus and the HDL level. Additional results are depicted in Table 1. In our previous study it was demonstrated that there is a high correlation between the 6 MWT distance measured by a standard 6 MWT and a smartphone-based 6 MWT while performing a free walk in the park. 3 While different aspects of physical fitness are measured by CPET and 6 MWT (maximal exercise capacity and submaximal exercise capacity respectively), a moderate correlation between measures of both tests has also been demonstrated in previous studies. 4,5 However, a study has demonstrated that in certain population such as severe heart failure a 6 MWT could be near to maximal effort. 6 The only moderate correlation could also be explained by the fact that the CPET was performed on a bicycle ergometer. Studies have already demonstrated differences in cardiopulmonary measures be
Tijdschrift: European journal of preventive cardiology
ISSN: 2047-4873
Issue: 15
Volume: 29
Pagina's: e350 - e352
Jaar van publicatie:2022