Longer life, disability free: Increases in life expectancy accompanied by increase in disability-free life expectancy, study shows

David Cutler, the Otto Eckstein Professor of Applied Economics in the Department of Economics, Mary Beth Landrum, Professor of Health Care Policy at Harvard Medical School, Michael Chernew, Leonard D. Schaeffer Professor of Health Policy at Harvard Medical School, and Kaushik Ghosh of the NBER, are co-authors of a new study that shows that the increase in life expectancy in the past two decades has been accompanied by an even greater increase in life years free of disability, thanks in large measure to improvements in cardio-vascular health and declines in vision problems. The study is described in a May 30 working paper released by the National Bureau of Economic Research.

"This suggests, for the typical person, there really is an act beyond work -- that once you reach age 65, you can likely look forward to years of healthy activity," Cutler said. "So this is good news for the vast bulk of people who can now look forward to healthier, disability free life, but it's also good news for medical care because it demonstrates the value of medical spending."

The study found that in 1992, the life expectancy of the average 65-year-old was 17.5 years, 8.9 of which were free from disability. By 2008, total life expectancy has risen to 18.8 years. In addition to the overall increase, the number of disability-free years increased, from 8.9 to 10.7, while the number of disabled years fell, from 8.6 to 8.1.

Driving those changes, Cutler and colleagues said, are two major treatment areas -- cardiovascular health and vision treatment.

"There has been an incredibly dramatic decline in deaths and disabilities from heart disease and heart failure," Cutler said. "Some of it is the result of people smoking less, and better diet, but we estimate that as much as half of the improvement is because of medical care, especially statin drug treatment, which is both preventing heart attacks and improving people's recovery."

Much of the improvement in vision health, he said, can be summed up in a single word -- cataracts.

"In the past, cataract surgery was very lengthy and technically difficult," Cutler explained. "That same surgery today can be done in an outpatient setting, so that complications and disability are significantly ameliorated."

While improved treatment for heart disease and vision problems have significantly added to disability-free life expectancy, Cutler said some conditions -- particularly dementia, neuro-degenerative disorders like Parkinson's disease and chronic-disabling conditions like diabetes- remain a concern.

To measure disability, Cutler and colleagues first turned to the Medicare Current Beneficiary Survey, an annual questionnaire that asks Medicare recipients whether they have difficulty with physical tasks like walking, getting in or out of bed or showering as well as day-to-day tasks like cooking, managing money or doing housework.

"The survey is designed to pick up how well people can live independently," Cutler said. "About half of all elderly people say they have difficulty with at least one item."

By combining those measurements of disability with life expectancy data culled from National Vital Statistics, Cutler and colleagues were able to create a unique measure not only of overall life expectancy, but how many of those years are likely to be disability-free.

"The data innovation we've made is to understand disability by time until death," Cutler said. "There are surveys of what share of people are disabled...but we really need to know where that disability falls in the life cycle."

While the data clearly shows those trends improving, Cutler said there are still additional questions to answer -- particularly about whether those increases hold true across all socio-economic groups and geographic regions. Recent data suggests that improvements have been uneven across the population.

Ultimately, though, Cutler said the study challenges the old idea of old age as a time when health problems and disabilities limited your options.

"It used to be that when you turn 70, your occupation became managing your health," he said. "Now you can increasingly just live your life."

The paper is titled "Understanding the Improvement in Disability Free Life Expectancy In the U.S. Elderly Population," NBER Working Paper No. 22306: http://www.nber.org/chapters/c13631.pdf.