August 26, 2013

If 75 is the new 40, what's 85?

You've probably heard repeatedly that 70 is the new 40--and perhaps also that 80 is the new 65.  If that's true, then quality of life for people who used to be considered old should be much better than previously. It turns out that the perception that things are better for the elderly is true—but only sort of.

A recent study by the well-known health economist David Cutler and his colleagues carefully analyzes data from the Medicare Current Beneficiary Survey, a rich source of information about the health and welfare of all 47 million Americans enrolled in Medicare. After painstaking study, the authors conclude that the “compression of morbidity” is for real: Americans truly have more years of life without disability today than they did 20 years ago. Someone who turned 65 in 1991 could anticipate living another 17.5 years, of which exactly half were spent with disability. Someone who turned 65 in 2003, by contrast, could look forward to living 18.2 years, of which fully 10.4 years would be disability-free, leaving 7.8 years of disability.

But all these averages--the average life expectancy at 65, average number of disability-free years--hide an important truth. What a given person will actually experience, just how much impairment he has in his final months or years, depends on what medical conditions he has. In fact, for some people, the experience of old age has gotten a great deal better; for others, it has gotten far, far worse.

Roughly speaking, people follow one of three possible paths in the last year or two of life and a similar pattern may well describe what happens in the last 5 or more years of life. One group of people die quite quickly and do well until the very end--these include people who have the most common forms of cancer and those who die very suddenly, perhaps from an accident or a heart arrhythmia. People in this group tend to die at a relatively young age and account for about 20% of all people who die. A second group of people have chronic organ system failure, for example congestive heart failure or chronic obstructive pulmonary disease, and have a course of slow decline, punctuated by periods of acute worsening followed by improvement. They do pretty well until the final 6-12 months of life and account for another 25% of the population.  A third group of people have poor long term function and have a slow decline, either because of dementia or because of that nebulous condition known as frailty in which multiple interacting medical problems interfere with daily activities. These include many of the oldest old and constitute 40% of deaths. The percentages do not add up to 100 because the remaining 15% cannot be readily classified as fitting into any of the 3 main groups.

What this means is that if you are in Group Three, what you will experience is not a "compression of morbidity," but a long, drawn-out period of decline. And the reality is that this third group, which is comprised largely of people with dementia, is going to grow as the other groups shrink.

It's already happening. Between 1997 and 2007, the death rate from heart disease fell 25%. Many people with heart disease are in that middle group who have pretty good functioning until their disease gets so severe that it gets in the way of what they want to do, though some have other diseases as well and are in the third, frail, group. So improvements in the prevention and treatment of heart disease--interventions such as exercise, diet, medications, and pacemakers--have meant fewer people dying of heart problems. But in the same ten year period, the death rate from Alzheimer's Disease increased by 50%. And all those people are in Group Three, those with the slow fade. 

So are things better or worse for older people? Maybe that's the wrong question. Maybe the answer is, it depends. 

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