Assessing the contribution of fibrinogen in predicting risk of death in men with peripheral arterial disease.
BACKGROUND
Although fibrinogen is known to be an independent population-level risk factor for cardiovascular disease in healthy individuals, less is known about its value for individual-level risk prediction.


OBJECTIVE
To assess the independent contribution of plasma fibrinogen to risk prediction in men with peripheral arterial disease.


METHODS
We used data from the 785 men randomized to placebo in the Lower Extremity Arterial Disease Event Reduction (LEADER) trial. Men were followed at 6-monthly intervals up to 3 years, during which 116 patients died. Multivariable standard and pooled logistic regression were used to model odds of death in the next 3 years or in a 6-month interval. The c-statistic and predictiveness curves were used to assess improvement in predictive ability.


RESULTS
Fibrinogen measured at baseline was an independent predictor of all-cause mortality risk (adjusted odds ratio [OR] 1.44, 95% confidence interval [CI] 1.02-1.94, for a 1 g L(-1) increase). Adding baseline fibrinogen to a set of other risk factors did not, however, substantially improve predictive ability. Similarly, fibrinogen measured at the start of a 6-month interval was independently associated with odds of death in the next 6 months (adjusted OR 1.65; 95% CI 0.96-2.73). Again, predictiveness curves with and without fibrinogen did not substantially differ, although the c-statistic increased by 0.011.


CONCLUSIONS
Although fibrinogen was independently associated with both 6-month and 3-year mortality risk, individual-level risk prediction was not substantially improved by including fibrinogen in risk models.
Bartlett
J W
JW
London School of Hygiene and Tropical Medicine, London, UK. jonathan.bartlett@lshtm.ac.uk
De Stavola
B L
BL
Meade
T W
TW
D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D003643:Death; D005340:Fibrinogen / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016017:Odds Ratio; D016491:Peripheral Vascular Diseases / Q000401:mortality*; D011237:Predictive Value of Tests; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D016019:Survival Analysis
D005340:Fibrinogen