Comparison of two questionnaires which measure the health-related quality of life of idiopathic pulmonary fibrosis patients
Zimmermann, C.S.; Carvalho, C.R.F.; Silveira, K.R.; Yamaguti, W.P.S.; Moderno, E.V.; Salge, J.M.; Kairalla, R.A.; Carvalho, C.R.R.
Brazilian Journal of Medical and Biological Research 40(2): 179-187
2007
ISSN/ISBN: 0100-879X PMID: 17273654 Document Number: 607995
The objective of the present study was to determine if there is a health-related quality of life ( HRQL) instrument, generic or specific, that better represents functional capacity dysfunction in idiopathic pulmonary fibrosis ( IPF) patients. HRQL was evaluated in 20 IPF patients using generic and specific questionnaires ( Medical Outcomes Short Form 36 ( SF-36) and Saint George's Respiratory Questionnaire ( SGRQ), respectively). Functional status was evaluated by pulmonary function tests, 6- min walking distance test ( 6MWDT) and dyspnea indexes ( baseline dyspnea index) at rest and after exercise ( modified Borg scale). There was a restrictive pattern with impairment of diffusion capacity ( total lung capacity, TLC = 71.5 +/- 15.6%, forced vital capacity = 70.4 +/- 19.4%, and carbon monoxide diffusing capacity = 41.5 +/- 16.2% of predicted value), a reduction in exercise capacity ( 6MWDT = 435.6 +/- 95.5 m) and an increase of perceived dyspnea score at rest and during exercise ( 6 +/- 2.5 and 7.1 +/- 1.3, respectively). Both questionnaires presented correlation with some functional parameters ( TLC, forced expiratory volume in 1 s and carbon monoxide diffusing capacity) and the best correlation was with TLC. Almost all of the SGRQ domains presented a strong correlation with functional status, while in SF-36 only physical function and vitality presented a good correlation with functional status. Dyspnea index at rest and 6MWDT also presented a good correlation with HRQL. Our results suggest that a specific instead of a generic questionnaire is a more appropriate instrument for HRQL evaluation in IPF patients and that TLC is the functional parameter showing best correlation with HRQL.