Friday, March 9, 2012

Gait Speed As A Medical Measure Of Vitality

As a person ages, we notice that some seem frail early in life yet others continue as vital for decades. Is there a way to detect frailty onset or even potential lifespan? There may be with a simple gait test.

New research suggests that “gait speed” can predict survival. The test is simple. Have the person walk a four meter distance starting from a standing still position. Measure the time with a stop watch. Speeds of greater than 1.0m/sec closely associates with healthier aging. Below 0.6m/sec correlates with poor health and less functional capability. A breakpoint of about 0.8m/sec separates individuals who will survive for less than or more than the median. Over 1m/sec suggests better than average survival and over 1.2m/sec suggests an even greater survival advantage. These are from a Jan 5, 2011 publication by Dr. Stephanie Studenski and colleagues in the Journal of the American Medical Association.
Fragility may seem to be just a subjective observation but, as I posted previously, there is a real science to frailty measurement.

Those predicted to live another five to ten years or more might be given greater consideration for preventive measures that normally take years to achieve a benefit. On the other hand, those with high risk for a short life span might be considered further for what modifiable circumstances could be adjusted to the patient’s benefit.

The data for these analyses were from nine studies conducted from 1986 to 2000. Each study had over 400 older participants, each community dwelling, whose gait speed was recorded and then followed for survival for five plus years. The graphic will illustrate the findings.

Here is a short video; click here and then click on "Walking Speed"
JAMA Report Video
And for a graphic of the results go here

These data help to differentiate the old (based on age) from the geriatric (based on biology). In an accompanying editorial, Dr. M. Cesari points out that not only is it useful to make this differentiation in older individuals but in other groups as well. For example in oncology practices, it is well known that performance status predicts outcome. Restated, those with low performance scores should normally not be treated with aggressive chemotherapy (the exception is in certain well defined situations) because the side effects are likely to outweigh the possible benefits. Surgeons, likewise, need to know who might be likely to encounter an adverse outcome. Gait speed might prove a useful way to select out who should likely not have chemotherapy or who should likely not have elective major surgery. Cesari points out that gait speed is not just a measure of leg function. It probably is a marker of a generalized physiologic function that correlates with health status.
Gait speed may become a marker to differentiate the chronologically old from the functionally geriatric. Check out your own rate.

No comments:

Praise for Dr Schimpff

The craft of science writing requires skills that are arguably the most underestimated and misunderstood in the media world. Dumbing down all too often gets mistaken for clarity. Showmanship frequently masks a poor presentation of scientific issues. Factoids are paraded in lieu of ideas. Answers are marketed at the expense of searching questions. By contrast, Steve Schimpff provides a fine combination of enlightenment and reading satisfaction. As a medical scientist he brings his readers encyclopedic knowledge of his subject. As a teacher and as a medical ambassador to other disciplines he's learned how to explain medical breakthroughs without unnecessary jargon. As an advisor to policymakers he's acquired the knack of cutting directly to the practical effects, showing how advances in medical science affect the big lifestyle and economic questions that concern us all. But Schimpff's greatest strength as a writer is that he's a physician through and through, caring above all for the person. His engaging conversational style, insights and fascinating treasury of cutting-edge information leave both lay readers and medical professionals turning his pages. In his hands the impact of new medical technologies and discoveries becomes an engrossing story about what lies ahead for us in the 21st century: as healthy people, as patients of all ages, as children, as parents, as taxpayers, as both consumers and providers of health services. There can be few greater stories than the adventure of what awaits our minds, bodies, budgets, lifespans and societies as new technologies change our world. Schimpff tells it with passion, vision, sweep, intelligence and an urgency that none of us can ignore.

-- N.J. Slabbert, science writer, co-author of Innovation, The Key to Prosperity: Technology & America's Role in the 21st Century Global Economy (with Aris Melissaratos, director of technology enterprise at the John Hopkins University).