Validation of the Chinese version of the Functional Performance Inventory Short Form in patients with chronic obstructive pulmonary disease

Abstract

Aims and objective: To determine the reliability and validity of the Chinese version of the Functional Performance Inventory Short Form (FPI-SF-C) in patients with chronic obstructive pulmonary disease in Beijing, China.

Background: The Functional Performance Inventory Short Form (FPI-SF) is a 32-item instrument designed to measure self-reported functional performance of patients with chronic obstructive pulmonary disease. This instrument had not been translated into Mandarin Chinese and tested for use in mainland China.

Design: Cross-sectional validation study with a two-week test of reproducibility.

Method: The FPI-SF was translated using forward and backward translation procedures and administered to 108 stable chronic obstructive pulmonary disease patients from outpatient clinics of three hospitals in Beijing, China. Pulmonary function and six-minute walking distance (6-MWD) tests were performed on the same day or within one week before the FPI-SF-C completion. Thirty of the patients participated in the reproducibility assessment.

Results: Cronbach's alpha for the FPI-SF-C total score was 0·89; subscales ranged from 0·70 (Body Care)-0·89 (Spiritual activities). Test-retest reliability (intraclass correlation coefficient) was 0·93 with subscales ranging from 0·73 (Body Care)-0·96 (Household Maintenance). No ceiling or floor effects were observed for total FPI-SF-C score. Total scores correlated significantly (p<0·05) with 6-MWD (r=0·56), modified Medical Research Council Dyspnoea Scale (MMRC) (r=-0·55), BODE index (r=-0·47), forced expiratory volume in one second (FEV(1)) (r=0·41) and FEV(1) % of predicted (r=0·26) and differentiated patients based on GOLD rating of COPD severity (χ(2)=16·22, p<0·001).

Conclusions: Results suggest the FPI-SF-C is a reliable and valid instrument for measuring functional performance in mainland Chinese patients with chronic obstructive pulmonary disease. Further psychometric testing in a wide range of subjects and an evaluation of its utility in clinical practice are warranted.

Relevance to practice: The FPI-SF-C may be useful for understanding difficulties in functional performance and evaluating the effect of treatment in Chinese patients with chronic obstructive pulmonary disease.