Women with Peripheral Arterial Disease Experience Faster Functional Decline than Men with Peripheral Arterial Disease

Abstract

Conclusion: Women with peripheral arterial disease (PAD) have greater loss of mobility and faster functional decline than men with PAD. Differences may be attributable to women with PAD having smaller baseline calf muscle area than men with PAD. Summary: The prevalence of PAD in older patients is the same in women as in men and may be higher (Vavra AK. Women's Health 2009;5:669-83). It has been demonstrated women with PAD have decreased lower extremity strength and greater functional impairment than men with PAD (McDermott MM. J Am Geriatric Soc 2003;51:222-8). In this study the authors determined whether there are sex differences in rate of functional decline over time and whether there are differences in rates of change of calf muscles characteristics over time between men and women with PAD. This was a longitudinal observational study. Rates of mobility loss, decline in six minute walk performance, and decline in walking velocity between men and women with PAD were determined at baseline and at 4 years of follow up. Baseline measurements of calf muscle characteristics and leg strength and changes in these muscle parameters between women and men with PAD were also determined at baseline and at 4 years of follow up. There were 380 men and women with PAD who completed a six minute walk test and were assessed for mobility, disability, and who underwent an evaluation of 4 meter walking velocity at baseline and annually for up to 4 years. Calf muscle characteristics were measured biannually with computed tomography. Outcomes included becoming unable to walk for 6 minutes continuously among patients who could walk continuously for 6 minutes at baseline. An additional outcome was mobility loss defined as becoming unable to walk for one-quarter mile or to walk up and down one flight of stairs without assistance. Adjustments were made for race, age, body mass index, the ankle brachial index, physical activity, comorbidities, and other confounders. At 4 years of follow-up, women were more likely to become unable to walk for 6 minutes continuously (HR, 2.3; 95%CI, 1.3-4.06; P = .004). Women were more likely to develop mobility disability (HR, 1.79; 95% CI, 1.3-3.03; P = .03). Women also had faster declines in walking velocity (P = .022) and distance achieved during the 6 minute walk (P = .041). After adjustment for a baseline sex differences in calf muscle area sex differences in functional decline were no longer statically significant. Comment: In this study women had smaller calf muscle area and lower calf muscle densities and less knee extension strength at baseline compared to men. With adjustments in the analysis sex differences in functional decline between women and men with PAD disappeared. This suggests poorer functional performance at baseline among women compared to men results in women being closer at baseline to thresholds for mobility loss and physical dysfunction. Interventions to improve lower extremity strength among women with PAD may slow their functional decline.