35 Development of the Exercise Adherence Scale (EXAS) in patients with low back pain differed by 2 points, and in all other cases, the difference was 1 point. Interrater reliability was much lower with Kqw = 0.36 (95%-CI 0.27–0.45), p < .001. The raters disagreed on the score in 142 cases, 77 ratings differed by 1 point, 53 ratings differed by 2 points, and the remaining 12 cases differed by 3 points. DISCUSSION The aims of the current study were to develop an instrument to measure adherence to frequency, intensity, and quality of performance of HBE programs recommended by a health-care professional and to evaluate its construct validity and intrarater reliability, resulting in the development of the EXAS. The instrument contains HBE recommendations from the health-care professional, patient-reported adherence to intensity and frequency of the HBE recommendations, and an observational component. This approach is in line with recommendations from Peek, Carey, Mackenzie, and Sanson-Fisher (2019) who suggested that adding an observational component to the assessment of adherence might more accurately reflect a patient’s efforts to follow HBE recommendations from a physical therapist (30). For the validity of the EXAS, the strength of the correlations between the EXAS, time to exercise, and motivation to exercise were moderate and confirmed the initial hypotheses. It was hypothesized that the associations would be moderate at best due to the large variety of factors related to adherence to HBE programs and the consistently moderate associations found in the literature (20,30). Divergent validity hypotheses were also all moderate as expected a priori. Both pain and disability were not significantly associated with the EXAS. It can be reasoned that pain and disability prevent patients from exercising or reduce adherence to HBE programs, which can potentially increase pain and disability. However, the opposite may also be true. Patients experiencing more pain and disability might be more motivated to exercise to reduce their symptoms. This ambiguity is reflected in the lack of association between pain and disability and the EXAS. A possible explanation for this can be found in the different strategies patients use to cope with pain and disability (31). Indeed, two of the most-reported strategies to cope with pain by patients with chronic LBP are praying and hoping (i.e. passive strategy) and increased behavioral activity (i.e. active strategy). The intrarater reliability of the quality of performance component of the EXAS is excellent (r = 0.87, 95% CI 0.83–0.92). With this score, the reliability estimate exceeds the standard threshold of 0.70 for use as a between-groups comparison measure (19). This result is very similar to the intrarater reliability results found in a study using a 10-point rating scale (32). Of the six physical therapists rating patient quality of performance using this 10-point scale, four scored between 0.82 and 0.88, with the remaining two scoring 0.72 and 0.74, respectively. The primary difference between this study and the current study 2
RkJQdWJsaXNoZXIy MTk4NDMw