Reproducibility and Validity of the Physical Activity Scale for the Elderly (PASE) Questionnaire in Patients After Total Hip Arthroplasty

Background. The assessment of physical activity is of concern in patients after total hip arthroplasty (THA). However, so far, no questionnaire has demonstrated adequate reproducibility and validity for assessing physical activity in these patients. Objective. The aim of this study was to evaluate the reproducibility and validity of the Physical Activity Scale for the Elderly (PASE) questionnaire in patients after THA. Design. This was a measurement study. Methods. Fifty patients who had undergone THA (25 women, 25 men), with an average age of 68 years, were evaluated. Of these patients, 25 were assessed between 2 and 7 months after surgery (THA(early)), and another 25 were assessed between 7 and 12 months after surgery (THA(late)). Reproducibility of the PASE questionnaire was evaluated by administering the questionnaire on 2 different occasions. Construct validity of the PASE questionnaire was assessed by comparing the physical activity level reported by patients with that objectively recorded by a body-mounted accelerometer. Reproducibility was investigated with intraclass correlation coefficients (ICC [2,1]) for reliability and standard errors of measurement (SEM) for agreement. Validity was investigated with Pearson correlation coefficients (r). Results. The ICC (2,1) for the PASE total score was .77 (95% confidence interval [95% CI]= .63, .86); the SEM was 23.0% (95% CI=19.2, 28.7). Validity correlation for the PASE total score was .38 (95% CI= .12, .60). No significant differences were found between THA(early) and THA(late) groups for reliability, agreement, and validity outcomes. Limitations. Reproducibility of the PASE questionnaire may have been underestimated because the physical activity of patients was compared between 2 consecutive but different weeks. Reliability and validity analyses were underpowered. Conclusions. Further study with a larger sample size is necessary to obtain precise reliability and validity estimates. Nevertheless, inadequate agreement calls into question the PASE questionnaire's ability to assess the physical activity level of patients after THA surgery.