You can expect that I’ll be blogging quite a bit about this topic over the next few days. A reader in Tyler Cowen’s comments offers this 2009 study:
Health insurance characteristics shift at age 65 as most people become eligi-
ble for Medicare. We measure the impacts of these changes on patients who are
admitted to hospitals through emergency departments for conditions with similar
admission rates on weekdays and weekends. The age profiles of admissions and
comorbidities for these patients are smooth at age 65, suggesting that the severity of illness is similar on either side of the Medicare threshold. In contrast, the
number of procedures performed in hospitals and total list charges exhibit small
but statistically significant discontinuities, implying that patients over 65 receive
more services. We estimate a nearly 1-percentage-point drop in 7-day mortality
for patients at age 65, equivalent to a 20% reduction in deaths for this severely ill
patient group. The mortality gap persists for at least 9 months after admission
I referred to three earlier studies, including one by Card, as
surveyed by Levy and Meltzer:
Card et al. use a
regression discontinuity approach to estimate the impact of Medicare
coverage on mortality. The basic idea is that if health insurance
significantly affects mortality in the short run, the dramatic increase
in health insurance coverage at age 65 as a result of Medicare should
translate into a reduction in mortality at age 65 relative to the
overall trend by age. In fact, the data show no such discontinuity:
mortality changes smoothly with age. Card et al. do find discrete,
significant increases in consumption of medical care. They also noted
some improvements in self-reported health at age 65, although many of
these effects are imprecisely estimated. One important exception is the
result for Hispanics and low-income minorities, both of whome see
significant increases in the probability of reporting good or better
health at age 65.Polsky et al. take a different approach to
estimating the impact of Medicare on health. They analyze changes in
the trajectory of self-reported health at age 65 adn find that receiving
Medicare increases the probability that respondents report excellent or
very good health. One surprising aspect of these findings is that
these shifts are observed both for respondents who were uninsured prior
to Medicare and for those who were otherwise insured. This result is
surprising because one would have expected benefits to be concentrated
in those who were not previously insured. The observed improvements are
also surprising because Medicare often provides less comprehensive
coverage than do most private insurance plans. Polsky et al.
hypothesize that the effect may be due to the stability of Medicare
coverage compared with private coverage.Finkelstein &
McKnight use data from the 1960s to see whether geographic areas with
lower insurance coverage rates prior to the enactment of MEdicare
experienced improvements in mortality following the enactment of
Medicare relative to areas with higher pre-1965 coverage rates. Earlier
work by Finkelstein using this same strategy documents significant
increases on hospital spending and utilization, but the work of
Finkelstein & McKnight finds no corresponding improvement in
mortality. The authors conclude that in its first 10 years, the
establishment of universal health insurance for the elderly had no
discernable impact on their mortality.” Of course, this result applies
to Medicare circa 1970; advances in medical technology and in the scope
of Medicare benefits since then may have greatly increased the marginal
health benefits of Medicare coverage.Taken together, these three
studies of Medicare paint a surprisingly consistent picture: Medicare
increases consumption of medical care and may modestly improve self
reported health, but has no effect on mortality, at least in the short
run. Whether there are long-term effects remains an open question; this
uncertainty reflects the limited generalizeability of the natural
experiment results.
The science is always evolving.
Obviously, if we get a lot of results showing that there is a big
effect at 65, I’ll change my mind; but right now, the bulk of the
evidence runs the other way. It’s worth noting that the later Card
paper itself notes that the aggregate figures show no mortality
improvement:
As is true for health insurance more
generally (see Levy and
Meltzer [2004]), it has proven more difficult to identify the health
impacts of Medicare.9 Most existing studies have focused on mor-
tality as an indicator of health.10 An early study by Lichtenberg
(2001) used Social Security Administration (SSA) life table data
to test for a trend-break in the age profile of mortality at age
65. Although Lichtenberg identified a break, subsequent analysis
by Dow (2004) showed that this is an artifact of the interval-
smoothing procedure used to construct the SSA life tables. Com-
parisons based on unsmoothed data show no evidence of a shift at
age 65 (Card, Dobkin, and Maestas 2004). Finkelstein and McK-
night (2005) explore trends in state-specific mortality rates for
people over 65 relative to those under 65, testing for a break
around 1966–the year Medicare was introduced. They also ex-
amine the correlation between changes in relative mortality after
1966 and the fraction of elderly people in a region who were unin-
sured in 1963. Neither exercise suggests that the introduction of
Medicare reduced the relative mortality of people over 65, though
it should be noted that the power of these analyses is limited.
How
could mortality improve at the micro level, and not at the macro
level? Increasing utilization of health services is not all mortality improving. As I note in the column, health care can kill as well as
heal–one estimates puts the death from nosocomial (treatment-induced)
infections at 80,000 a year. So while it’s entirely possible–indeed
certain–that some number of people are saved by having insurance, it’s
also very likely that some number of people are saved by not having it,
or having less generous insurance, because they don’t go in for a
treatment that would have killed them.
The 2009 paper was
looking at a small subset of conditions that are urgent, and which we’re
relatively adept at treating. But it may be washed out by the people
who die having knee surgery.
This is, of course, why comparative
effectiveness research is very popular among wonks. But it’s trickier
than it sounds, because patients are very heterogenous. I actually
expect this problem to go down in the next twenty years or so, as better
genomics gives us more of a handle on which treatments work for whom.
One
thing it does suggest is that if we want to maximize the benefits from
expanding insurance coverage, we really need to wage a scorched-earth
battle against nosocomial infection. Hospital hygeine has slipped
massively from where it was in the thirties, because antibiotics have
made health care workers lless urgent about it. We need to return to
the OCD days of yore.
