Reliability of Conducting The 30-Second Chair Stand Test Virtually Among Individuals with Osteoarthritis

Lower extremity (LE) muscular strength is important for maintaining physical function and mobility. With a general agerelated decline in LE strength, the risk of mobility issues and falls increases [1]. A repeated chair stand test is commonly used to assess LE strength in older adults [2]. Originally the test measured the time taken to perform either five or ten sit-to-stand repetitions but as many individuals in the target populations were unable to meet the minimum requirement it resulted in a floor effect [2,3]. The test was then modified to become the 30-second chair stand test (30s CST), which measured the number of sit-to-stand repetitions an individual could perform during a 30-second period. Essentially shifting from a pre-determined number of repetitions to a pre-determined time interval in order to capture a wider range of ability levels [2].

The 30s CST is a recommended performance-based measure for assessing physical function in individuals with hip osteoarthritis (OA) [4,5]. OA is a leading cause of disability among older adults and can cause substantial functional impairment [6]. Previous research has affirmed in-person validity and reliability of the 30s CST among individuals with OA, but with the COVID-19 pandemic there has been a need to pivot to virtual assessments [4,8]. It is, therefore, important to explore the impact of conducting the 30s CST virtually. Bowman and associates confirmed the safety and validity of conducting the test virtually, but reliability was not examined [7]. To our knowledge, there are no studies that demonstrate the reliability of conducting the 30s CST virtually. Our objective was to explore the intra-rater and inter-rater reliability of the 30s CST when administered virtually among individuals with hip OA.

Design/Sample

This cross-sectional study was part of a larger ongoing RCT, which is evaluating the feasibility of “HIPPER”, an eHealth approach to hip replacement prehabilitation education [9]. The participants were referred by the Osteoarthritis Service Integration System (OASIS) in Vancouver, Canada. To be included, participants had to be ≥50 years of age, have hip OA, be waitlisted for a total hip replacement surgery, and have access to the Internet. Individuals were excluded if they were unable to communicate in English, anticipated a health condition/procedure that could interfere with their surgery, or had already had a previous total hip replacement. Ethical approval was obtained from the university Research Ethics Board (H16-02553) and the Vancouver Coastal Health Research Institute (V16-02553).

Protocol

Once recruited, participants agreed to have a one-to-one virtual meeting with author 1 using a secure Zoom account. Prior to their meetings, all participants were asked to have a firm chair with a 17” (43 cm) seat height in a place that was visible by their camera. To start, we asked participants to provide contact details and their address in case emergency services needed to be sent to their location. Participants were then provided with a standardized set of instructions regarding the 30s CST and performed the test once. We recorded the 30s CSTs on Zoom, and the scores were logged. All data were stored in password protected files.

Intra-rater reliability

Approximately four months after conducting all 30s CSTs, the participant IDs associated with each video were randomized for the purposes of blinding, and the 30s CST recordings were reviewed by author 1 again. The second set of scores were then compared to the initial scores. Author 1 is a trained research assistant with a background in kinesiology and qualitative research.

Inter-rater reliability

Simultaneously to author 1’’s second review, the recordings were independently reviewed by an experienced physical therapist (author 6), who was blinded to the previous scores. The two raters’ scores were then compared.

Statistical analysis

We calculated the intra-rater ICC estimates and their 95% confidence intervals using SPSS based on a single-rater, absolute agreement, two-way mixed-effects model. Inter-rater ICC estimates and their 95% confidence intervals were calculated based on a single-rater, absolute agreement, two-way random-effects model. Bland-Altman plots were used to display and compare differences in the measurements. Generally, ICC values less than 0.5 indicate poor reliability, values between 0.5 and 0.75 indicate moderate reliability, values between 0.75 and 0.9 indicate good reliability, and values greater than 0.90 indicate excellent reliability [10].

A total of 46 participants performed the 30s CST. Participants mean age was 64.24 ± 8.74 years, and 25 were female. Only 44 30s CSTs were available for intra-rater reliability analysis due to missing baseline scores. No injuries, adverse events, or safety issues were observed/reported.

Intra-rater reliability

The ICC value was 0.99 (95% CI: 0.98-1.00), indicating excellent intra-rater reliability. The Bland-Altman plot (Figure 1) shows a mean difference of -0.1522 with 89% of values falling within the 95% CI for the Limits of Agreement.

Inter-rater reliability

The ICC value was 0.99 (95% CI: 0.98-0.99), indicating excellent inter-rater reliability. The Bland-Altman plot (Figure 2) shows a mean difference of -0.0227 with 96% of values falling within the 95% CI for the Limits of Agreement.

The purpose of this study was to explore the intra-rater and inter-rater reliability of the 30s CST when administered virtually. Our findings suggest that the 30s CST can be safely administered virtually with excellent reliability.

With a global increase in telehealth and virtual research, the findings provide further evidence for virtual administration of a recommended performance measure for adults with OA. Virtual assessments can be more efficient and convenient for both clinical practice and research purposes. Despite the excellent reliability, there were four notable challenges to conducting the 30s CST virtually. Firstly, despite the instructions given in advance regarding the chair test, it was difficult to ensure standardization and consistency of chair seat height and it was not feasible for all to find a chair with the correct height. Secondly, there were issues related to video, audio, internet connectivity, and general participant technology competency. These were partially mitigated by using trained clinicians/researchers, providing clear instructions, doing trial runs, and closing background applications. Thirdly, given the online nature, the clinician/researcher is limited by the camera angle and the view on screen. Depending on the participant’s space, this may not provide a full view. Finally, the clinicians/researchers cannot provide physical assistance when setting up the equipment or in the case of an adverse event. It is, therefore, important to develop a safety plan, including having a second person present and the address to send emergency services to.

The ability to reliably conduct the 30s CST virtually provides a valuable and convenient option for clinicians/researchers to conduct a widely used and recommended measure of physical function for adults with hip OA. Future research should address the described challenges and continue to explore the feasibility and reliability of conducting the 30s CST in other patient populations.

Clinical Messages

1. The 30s CST is a recommended performance-based measure for assessing physical function in individuals with hip osteoarthritis (OA) but with the COVID-19 pandemic there has been a need to pivot to virtual assessments.

2. To our knowledge, there are no studies that demonstrate the reliability of conducting the 30s CST virtually.

3. Our findings suggest that the 30s CST can be safely administered virtually with excellent intra- and inter-rater reliability.

4. The ability to reliably conduct the 30s CST virtually provides a valuable and convenient option for clinicians/ researchers to conduct a widely used and recommended measure of physical function for adults with hip OA.

None.

None.

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