JMIR Publications

ABSTRACT

Background:

The 6-minute walk test (6MWT) is a common method to assess the exercise capacity of people with many health conditions, including persistent pain. However, it is conventionally performed with in-person supervision in a hospital or clinic, therefore requiring staff resources. It may also be difficult when in-person supervision is unavailable, such as during the COVID-19 pandemic or when the person is geographically remote. A potential solution to these issues could be to employ the global positioning system (GPS) to measure walking distance.

Objective:

This study aimed to assess the validity of a GPS-based smartphone app to measure walking distance as an alternative to the conventional 6MWT, in a persistent pain population. The secondary aim of this study is to estimate the difference between the pain evoked by the two test methods.

Methods:

People with persistent pain (n=36) were recruited to complete: 1) a conventional 6MWT on a 30m shuttle track and 2) 6MWT measured by a smartphone app using the global positioning system, performed on outdoor walking circuits. Tests were performed in random order, separated by a 15-minute rest. The 95% limits of agreement were calculated using the Bland-Altman method, with a specified maximum allowable difference of 100m. Pain was assessed on an 11-point numerical rating scale before and after each walk test.

Results:

The mean 6MWD measured by the GPS-based smartphone app was 13.2m higher (SD 46, 95%CI [−2.7, 29.1]) than the 6MWD assessed in the conventional manner. The 95% limits of agreement were 103.9m (95%CI [87.4, 134.1]) and −77.6m (95%CI [−107.7, −61.0]), which exceeded the maximum allowable difference. Pain increased in the conventional walk test by 1.1 points (SD 1.0 point), while pain increased in the app test by 0.8 points (SD 1.4 points).

Conclusions:

In individuals with persistent pain, the two methods of assessing 6MWT may not be interchangeable due to limited validity. Potential reasons for the differences between the two methods might be attributed variation in track layout (shuttle track vs continuous circuit), poor GPS accuracy, deviations from the 30m shuttle track, human variability in walking speed, and the potential impact of a first test on the second test due to fatigue, pain provocation, or a learning effect. Future research is needed to improve the accuracy of the GPS-based approach. Despite its limitations, the GPS-based 6MWT may still have value as a tool for remote monitoring that could allow individuals with persistent pain to self-administer frequent assessments of their functional capacity in their home environment.