Prediction of all-cause mortality in endovascularly treated patients with peripheral arterial disease of the lower extremities

Abstract

Objectives

Lower extremity peripheral arterial disease (PAD) is associated with increased morbidity and mortality. The primary objective of the study was to identify nonspecific risk factors for 2- and 5-year all-cause mortality in endovascularly treated patients with PAD. The secondary objective was to develop a clinically applicable scoring system to estimate the probability of 2- and 5-year all-cause mortality based on our results.

Methods

We performed a retrospective study using data from patients with PAD who underwent endovascular treatment between January 2016 and December 2018. All data were collected from electronic medical records. A Cox proportional hazards regression model was used to examine the association between variables and all-cause mortality. Multivariate analyses were performed after adjusting for age, chronic limb-threatening ischaemia (CLTI), creatinine and fibrinogen in model 1, and for age, hypertension, diabetes mellitus, sex, smoking, dyslipidemia, CLTI, chronic obstructive pulmonary disease, malignancy, atrial fibrillation, heart failure with reduced ejection fraction, coronary artery disease, fibrinogen and creatinine in model 2. Variables associated with mortality with p-value <.02 in all analyses were included in the scoring system. The predictive performance of the scoring system was evaluated using the Area Under Curve (AUC) of Receiver Operating Characteristic curve.

Results

A total of 676 patients with a mean age of 68.6 ± 9.74 years were analyzed, 66.7% of patients had CLTI. The 2-year mortality rate was 22.3%; 29.5% in patients with CLTI and 8% in patients with claudications. The 5-year mortality rate was 48.8%; 60.5% in patients with CLTI and 25.3% in patients with claudications. CLTI presence, creatinine, age and fibrinogen were included in the scoring system. Based on the cut-off values of creatinine >102.4 umol/l, fibrinogen >5.41 g/L, age ≥68 years and CLTI presence, patients were categorized into five groups. For 2-year mortality, a score of 0 points corresponded to a 5.0% risk of death, 1 point to an 11.1% risk, 2 points to a 23.0% risk, 3 points to a 41.7% risk and a score of 4 points to a 63.1% risk of death (AUC 0.73; p = .000). For 5-year mortality, a score of 0 points corresponded to a 13.5% risk of death, 1 point to a 31.3% risk, 2 points to a 57.1% risk, 3 points to a 79.5% risk and a score of 4 points to a 91.9% risk of death (AUC 0.74; p = .000).

Conclusions

The all-cause 2-year mortality rate in patients with PAD was 22.3%, and the 5-year mortality rate was 48.8%. The strongest associations with 2- and 5-year mortality were observed for CLTI presence, creatinine, age and fibrinogen. The scoring system based on these variables predicts 2- and 5-year all-cause mortality risk in patients with PAD, with a probability approaching 75%.