Racial differences in functional decline in peripheral artery disease and associations with socioeconomic status and education

Objective The objective of this study was to determine whether blacks with lower extremity peripheral artery disease (PAD) have faster functional decline than whites with PAD. Methods Participants with ankle-brachial index <0.90 were identified from Chicago medical centers and observed longitudinally. Mobility impairment and the 6-minute walk were assessed at baseline and every 6 to 12 months. Mobility loss was defined as becoming unable to walk up and down a flight of stairs or to walk ¼ mile without assistance. Results Of 1162 PAD participants, 305 (26%) were black. Median follow-up was 46.0 months. Among 711 PAD participants who walked 6 minutes continuously at baseline, black participants were more likely to become unable to walk 6 minutes continuously during follow-up (64/171 [37.4%] vs 156/540 [28.9%]; log-rank, P =.006). Black race was associated with becoming unable to walk 6 minutes continuously, adjusting for age, sex, ankle-brachial index, comorbidities, and other confounders (hazard ratio, 1.45; 95% confidence interval, 1.05-1.99; P =.022). This association was attenuated after adjustment for income and education (P =.229). Among 844 participants without baseline mobility impairment, black participants had a higher rate of mobility loss (64/209 [30.6%] vs 164/635 [25.8%]; log-rank, P =.009). Black race was associated with increased mobility loss, adjusting for potential confounders (hazard ratio, 1.42; 95% confidence interval, 1.04-1.94; P =.028). This association was attenuated after additional adjustment for income and education (P =.392) and physical activity (P =.113). There were no racial differences in average annual declines in 6-minute walk, usual-paced 4-meter walking velocity, or fast-paced 4-meter walking velocity. Conclusions Black PAD patients have higher rates of mobility loss and becoming unable to walk for 6 minutes continuously. These differences appear related to racial differences in socioeconomic status and physical activity.