Women suffering from lower extremity peripheral arterial disease (PAD) had greater mobility loss and faster functional decline compared with men with the same condition. Researchers attributed these differences to smaller baseline calf muscle areas in female PAD patients, according to a study in the Feb. 8 Journal of the American College of Cardiology.
“[L]ittle is known about sex differences in rates of functional decline or changes in calf muscle characteristics over time between men and women with PAD,” the authors wrote.
To bolster sparse data, Mary M. McDermott, MD, of the Feinberg School of Medicine at Northwestern University in Chicago, and colleagues evaluated 380 patients with PAD (32 percent women) to compare rates of mobility loss, decline in six-minute walk performance and decline in walking velocity between both sexes after a four-year follow-up.
During the study, researchers also measured calf muscle characteristics via biannual CT imaging. The researchers defined mobility loss as being unable to walk for a quarter mile or walk up and down a flight of stairs without assistance.
The mean age of patients was 76 for women and 74.2 for men. Women within the study were more likely to be African-American, have knee arthritis, disc disease and had lower prevalence of angina compared with men.
The researchers reported that women walked fewer blocks per week, had poorer six-minute walk performance, smaller calf muscle areas, lower calf muscle density and worse knee extension strength compared with men.
After the researchers adjusted for calf muscle density, female sex with greater decline in usual-paced walking velocity was no longer statistically significant. For this reason, the authors speculated that lower baseline calf muscle areas among women may link the female sex with faster functional decline in PAD patients. However, these sex differences in calf muscle fat were not associated with faster functional decline in women.
The researchers noted that male PAD patients had more rapid deterioration in lower extremity muscle characteristics and strength compared with women, and were more susceptible to loss of favorable muscle characteristics and function compared with women. This reason could protect male PAD patients against functional decline.
“Further study is needed to determine whether interventions to increase calf muscle area, to improve lower extremity strength among women with PAD, or both can slow their faster functional decline as compared with men with PAD,” the authors concluded.