The SAFE (SGRQ score, air-flow limitation and exercise tolerance) Index: a new composite score for the stratification of severity in chronic obstructive pulmonary disease.
BACKGROUND
This study was proposed to develop a composite of outcome measures using forced expiratory volume percentage of predicted, exercise capacity and quality of life scores for assessment of chronic obstructive pulmonary disease (COPD) severity.


METHODS
Eighty-six patients with COPD were enrolled into a prospective, observational study at the respiratory outpatient clinic, National University Hospital Malaysia (Hospital Universiti Kebangsaan Malaysia--HUKM), Kuala Lumpur.


RESULTS
Our study found modest correlation between the forced expiratory volume in 1 s (FEV(1)), 6 min walk distance and the SGRQ scores with mean (SD) values of 0.97 (0.56) litres/s, 322 (87) m and 43.7 (23.6)%, respectively. K-Means cluster analysis identified four distinct clusters which reached statistical significance which was refined to develop a new cumulative staging system. The SAFE Index score correlated with the number of exacerbations in 2 years (r = 0.497, p<0.001).


CONCLUSIONS
We have developed the SGRQ, Air-Flow limitation and Exercise tolerance Index (SAFE Index) for the stratification of severity in COPD. This index incorporates the SGRQ score, the FEV(1) % predicted and the 6 min walk distance. The SAFE Index is moderately correlated with the number of disease exacerbations.
Azarisman
Mohd Shah
MS
Department of Medicine, International Islamic University Malaysia, Jalan Hospital Campus, Kuantan, Pahang, Malaysia. risman1973@hotmail.com
Fauzi
Mohd Anshar
MA
Faizal
Mohd Perdaus Ahmad
MP
Azami
Zaharim
Z
Roslina
Abdul Manap
AM
Roslan
Harun
H
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016000:Cluster Analysis; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011788:Quality of Life; D011795:Surveys and Questionnaires