Assessment of activity status and survival according to the Canadian Cardiovascular Society angina classification.
BACKGROUND
Despite its widespread use, limited data on the validity of the Canadian Cardiovascular Society angina (CCSA) classification relative to other measures of functional status have been reported.


OBJECTIVE
To assess the validity of the CCSA classification by comparing it with the Duke Activity Status Index (DASI) and evaluate its prognostic significance with respect to long-term mortality.


METHODS
The study population consisted of 1407 patients who underwent cardiac catheterization between 1992 and 1996. The median follow-up period was 9.7 years (interquartile range 6.1 to 11.1 years) and the mortality status as of December 31, 2004 was available for all patients.


RESULTS
The first three CCSA classes were inversely related to the DASI. The mean (+/- SD) scores were as follows: class I, 31.4+/-16.7; class II, 22.5+/-15.4; class III, 14.7+/-14.3; and class IV, 15.5+/-14.9 (P<0.01). Increasing CCSA class was associated with increased long-term mortality, even after adjusting for baseline characteristics. Chest pain course was also an important modulator of mortality among class III and IV patients; one-year mortality rates were 8.1% among unstable patients compared with 4.8% among patients with stable or progressing course.


CONCLUSIONS
CCSA classes I to III were inversely related to DASI scores and linearly associated with mortality. The similarity in outcomes among class III and IV patients is probably explained by the confounding effect of the stability of the patients' symptoms. The higher mortality risk among class III and IV patients with an unstable course provides impetus for a revised CCSA definition incorporating this information.
Kaul
Padma
P
Division of Cardiology, University of Alberta, Edmonton, Alberta T6G 2M8, Canada. pkaul@ualberta.ca
Naylor
C David
CD
Armstrong
Paul W
PW
Mark
Daniel B
DB
Theroux
Pierre
P
Dagenais
Gilles R
GR
D000704:Analysis of Variance; D000787:Angina Pectoris / Q000145:classification* / Q000175:diagnosis / Q000401:mortality; D002170:Canada; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index; D012955:Societies, Medical; D013223:Statistics as Topic; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome