Today's open access paper caught my eye for the assertion that time spent in poor health at the end of life is actually decreasing over the recent period of decades of slowly increased life expectancy. This is not the conventional wisdom, but data is data, at least for this sizable study population. Compression of morbidity, a shortening of the period of age-related disease in later life, is a stated goal for much of the aging research community, but whether or not compression of morbidity is either (a) possible, or (b) already happening in at least some populations is a much debated topic.
If aging is simply slowed outright, then the period of disability and increased mortality could in principle be more drawn out, and less harmful for most of that time. But if aging is postponed rather than slowed then the period of disability would not be lengthened or improved. Given the way in which the relevant human data is recorded, with few fine details, particularly in the earlier, pre-clinical stages of age-related disease, it is hard to determine what exactly is taking place. It seems likely that neither slowing only nor postponing only is a good way to describe the present trend in slowly increased life expectancy, achieved without actively aiming to treat the underlying mechanisms of aging.
Rising life expectancy at older ages has raised concerns that the period of poor health and disability prior to death is growing. Research typically addresses this topic with the implicit assumption that advancing age is the main risk factor for declining health. However, the onset of several health conditions, including end-of-life depression and cognitive decline, is more closely linked to years of life remaining than years lived. Comparing the health of older adults who are the same proximity to death (for example, comparing all adults in their last year of life) may yield different insights than comparing adults who are the same age, but differing distances from death (for example, comparing all 70 year-olds).
In this paper, I examine trends and inequalities in aging from the perspective of time to death, rather than time since birth. I compare three indictors of health - self-rated health (SRH) and two self-reports of disability - in the last 6 years of life among adults dying at ages 65+ across time, sex, age, race, and educational attainment. SRH is a subjective and self-reported indicator of health. While the two disability measures are also self-reported, they serve as more objective assessments of requiring assistance. This study is the first to examine annual trends in SRH at the end of life, as well as the first to produce national estimates of end-of-life SRH for several subpopulations.
Despite concerns about expanding morbidity at the end of life, I find that the amount of time individuals report unfavorable health in the last six years of life declined two months from 1987-2008. To the author's knowledge, this is the first study to examine trends in SRH at the end of life. I also find no change in the length of time spent with at least one end-of-life IADL or ADL limitation from 1997-2008, barring a slight increase in the most recent period.
These findings are generally consistent with prior work that documents an unchanging prevalence of ADL limitations from 1995-2009 in the last 2 years of life. While others use repeated cross sections of the Medicare Current Beneficiaries Survey linked to death records from 1991-2009 to document a decline in the prevalence of ADL and IADL limitations in the last 5 years of life in the 1990's, they find no significant change in the following decade (the main focus of this analysis). However, my findings are in contrast to those by that consider six major chronic conditions and find that the adult disease burden may have grown over a similar period. Perhaps our findings differ because of the operationalization of disability versus chronic conditions. A growing disease burden might not translate to a higher prevalence of reporting one or more limitation, especially if the increases in chronic conditions are among people who already have at least one disability.