The Patient-specific Functional Scale: A Simple Functional Performance Tool in Patients With Cardiovascular Disease.

Purpose: This study aimed to evaluate the reliability and construct validity of the patient-specific functional scale (PSFS) in patients with cardiovascular disease (CVD).

Methods: Stable patients with CVD were recruited from outpatient cardiology clinics. Reliability and validity were examined using a cross-sectional study design. Patients with CVD (n=140) were included to assess the test-retest reliability using the interclass correlation coefficient model 2,1 (ICC2,1), measurement errors, as well as construct validity of the PSFS. Construct validity was tested by comparing the PSFS with a 6-minute walk test (6MWT) and Duke Activity Status Index (DASI). The PSFS would be hypothesized to demonstrate at least moderate correlations (>0.50) with the 6MWT and DASI.

Results: A total of 140 patients (85 males) with CVD completed the PSFS. The average age of the participants was 59 years. The PSFS showed excellent reliability with an ICC2,1, of 0.92 (95% CI: 0.90-0.94). The PSFS was correlated with the DASI (r=.88, p<.001) and the 6MWT (r=.89, <.001). The SEM was 0.37 points, and the MDC at a 95% CI was 1.01 points. There were no floor or ceiling effects.

Clinical relevance: This scale can help rehabilitation nurses to identify patients' functional needs and personalize rehabilitation interventions.

Conclusion: This study provides evidence supporting the reliability and validity of the PSFS in the CVD population in outpatient settings.