Measuring Change in Health Status Over Time (Responsiveness): A Meta-analysis of the SF-36 in Cardiac and Pulmonary...

The purpose of this meta-analysis is to gather and investigate pooled information on the responsiveness of the main patient outcome measure in cardiac rehabilitation (CR) and pulmonary rehabilitation (PR). The main outcome measure in CR and PR has been found to be the Medical Outcomes Study Short Form-36 health survey (SF-36).

A previous systematic effectiveness review of this literature was used as the basis of this statistical analysis, with the bulk of articles being observational studies.

This meta-analysis assessed articles on CR that used SF-36 pre and post "within" (per interventional group) mean scores and in the PR literature that used the SF-36 and the Chronic Respiratory Questionnaire (CRQ) "within" change scores.

Each group of patients in the chosen literature were taken to represent a single group, so that studies such as randomized controlled trials were listed twice. We undertook a correlation analysis between SF-36 pre and post "within" mean scores in the CR literature. In the PR literature, we undertook a correlation analysis between SF-36 and the CRQ "within" change scores; this involved Spearman correlation coefficients.

The SF-36 Mental Composite Score domain is the most responsive of the composite SF-36 domains, with the Physical Composite Score showing less ability to discriminate in the higher SF-36 scores. In the individual domains, Role Emotional scored r=0.52, P≤.001 with only 27% of the variance explained, and Role Physical with r=0.49, P≤.005 had only 24% of the variance explained. In the PR literature Spearman rank correlation coefficient shows that SF-36 Physical Composite Score has a weaker correlation to the CRQ at 0.39 than the SF-36 Mental Composite Score, which was 0.63.

This suggests that the SF-36 is not suited as a pre- to postprogram assessment tool for CR and PR. More studies, however, need to be conducted particularly in CR with regard to the responsiveness of the SF-36.