Diabetic foot ulcers linked with activity pattern

Lower levels of activity, rather than higher levels, appear to precede the development of foot ulcers in people with diabetes, according to a new study.

"We were surprised to find that individuals developing ulcers were apparently less active than those who did not, " Dr. David G. Armstrong, of Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, and colleagues write in the medical journal Diabetic Care.

The researchers explain that many clinicians, "including ourselves," have long thought that the combination of excessive pressure and frequent mechanical stress produced by physical activity lead to the formation of diabetic foot ulcers. However, a more important factor may be "peaks and valleys" in activity, rather than overall activity, their new findings suggest.

The team examined activity levels in 100 consecutive diabetic patients, average age 68.5 years, who were at high risk for developing foot ulcers. All the participants wore a computerized activity monitor to measure the number of steps taken over a period of time.

The researchers collected data continuously over a minimum of 25 weeks or until ulceration occurred. Eight percent of the subjects developed foot ulcers.

Subjects who developed ulcers had significantly lower average daily activity compared with those who did not develop ulcers. However, the variability in level of activity was much higher in the group that developed ulcers.

"In other words," the investigators write, the pattern of activity "appeared to be characterized by periods of inactivity punctuated by relatively sudden pulses of activity taken over a short period of time."

This pattern was most noticeable in the two weeks before an ulcer developed.

Based on their findings, the researchers suspect that vulnerable skin "if not stressed consistently, may be at even higher risk for damage."

If this potentially dangerous "pulse" of activity can be identified, maybe this information can be provided to the patients or their doctor so they can modify their activity - "essentially smoothing out those peaks and valleys of activity," Armstrong told Reuters Health.

SOURCE: Diabetes Care, August 2004.