Abstract
Background: SF-12 is a validated questionnaire for measuring patient-reported functional health and well-being. There is a paucity of knowledge on whether the physical component scale, PCS, part of the SF-12, could predict lung function longitudinally.
Methods: In the Hordaland County Cohort Study, 1527 subjects, 52% men, aged 26-82 years at baseline performed post bronchodilator spirometry in 1996-97 and in 2003-2005. SF-12 was used as measurement of health related quality of life and PCS score was main predictor. We performed linear regression analyses of PCS and post BD FEV1 in 2003-05, and adjusted for sex, age, height, educational level, occupational exposure, smoking habits, packyears and baseline FEV1.
Results: Mean FEV1 in 2003-2005 was 3.11L (SD 0.9). Mean baseline FEV1 was 3.46 L (SD 0.9), and mean PCS score of the SF 12 was 50.4 (SD 8.4). Coefficients (95% CI) for significant predictors in the multivariate model were; -0.03 (-0.03, -0.027) for age, 0.089 (0.02, 0.16 for ex smokers vs never smokers, 0.025 (-0.05, 0.1) for current smokers vs never smokers, 0.43 (0.36, 0.50) for men vs women, 0.14 (0.07, 0.21) for intermediate vs lower education, 0.14 (0.06, 0.23) for higher vs lower education, -0.01 (-0.02, -0.01) for packyears and 0.008 (0.005, 0.011) for PCS sum score. PCS was a significant risk factor for lower FEV1, but the significance did not remain when adjusting for baseline FEV1.
Conclusion: The physical sum score of the SF-12 predicts lower lung function at follow up, but the effect did not remain after adjusting for baseline lung function.
However, this result shows that in absence of spirometry, SF-12 may serve as a simple and effective tool to identify persons at risk of COPD.
- © 2011 ERS