The Effect of Supervision on Walking Distance in Patients with Intermittent Claudication: A Meta-analysis. 2014

Abstract
BACKGROUND:
A number of reviews have reported the influence of exercise therapy (ET) for the treatment of intermittent claudication (IC). However, a complete overview of different types of ET is lacking. The aim of this meta-analysis was to study the effect of supervision on walkingcapacity in patients with IC. It was hypothesized that there was a positive treatment effect in relation to the intensity of supervision and improvement in walking capacity (i.e., a “dose-response” hypothesis).
METHODS:
A systematic search in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE databases was performed. Only randomized controlled trials (RCTs) evaluating the efficacy of an ET in IC were included. Type of supervision, treadmill protocol, length of ET, total training volume, and change in walking distance were extracted. RCTs were categorised according to type of support: no exercise, walking advice, home-based exercise (HB-ET), and supervised exercise therapy (SET). A standardised mean difference between pre- and post-training maximalwalking distance (MWD) and pain-free walking distance (PFWD) was calculated for all subgroups at 6 weeks, and 3 and 6 months of follow up.
RESULTS:
Thirty studies involving 1406 patients with IC were included. The overall quality was moderate-to-good, although number of included patients varied widely (20-304). The intensity of supervision was directly related to MWD and PFWD. SET was superior to other conservative treatment regimens with respect to improvement in walking distances at all follow-ups. However, the difference between HB-ET and SET at 6 months of follow up was not significant.
CONCLUSION:
Supervised exercise therapy for intermittent claudication is superior to all other forms of exercise therapy. Intensity of supervision is related to improved walking distance.

My comments:

This a great paper that gives some pools data from 28 randomized controlled trials testing the effects of various walking programs and the effects of supervision. Advice to walk more had small benefits: home-based walking programs being slightly better, while supervised programs were better (well over twice as good when tested at 6 weeks, 3 months and 6 months). The authors also concluded that 12 weeks appears to be the optimal length of a supervised exercise program. Most of the gains in pain free walking distance and max walking distance occur in that period. After that point improvements appear to level off. So, the 12 week point might be an ideal time to transition to a home based walking program, and 12 weeks/3 months is what is recommended by the American Heart Association and TASC II.

One thing I thought was interesting was in the conclusion they noted that the supervised exercise was more likely to be done on a treadmill, while the home programs were more likely to be done outdoors. I think it likely that this could be part of the reason for the improvement, because on a treadmill a person knows exactly how far and how fast they are walking. This likely keeps them honest and unlikely to slow down, since they have to push a button to do so. In outdoor walking one might gradually slow down and be completely unaware of it.