Mobility Trajectories at the End of Life: Comparing Clinical
Condition and Latent Class Approaches
June R. Lunney, PhD, RN,* Steven M. Albert, PhD,
Robert Boudreau, PhD,
Diane Ives, MPH,
Suzanne Satterﬁeld, MD,
Anne B. Newman, MD,
and Tamara Harris, MD,
for the Health Aging
and Body Composition Study
OBJECTIVES: To assess mobility disability trajectories
before death in a large sample of very old adults using two
analytical approaches to determine how well they corre-
DESIGN: Decedent sample from the Health, Aging and
Body Composition (Health ABC) Study. Data were col-
lected between 1997 and 2015.
SETTING: Pittsburgh, Pennsylvania, and Memphis, Ten-
PARTICIPANTS: Individuals randomly selected from
well-functioning white Medicare beneﬁciaries and all black
community residents meeting age criteria (70–79)
(N = 3,075).
MEASUREMENTS: Participants were interviewed in per-
son or by phone at least every six months throughout the
study. Of the 1,991 participants who died by the end of
the study, 1,410 had been interviewed for 3 years before
death, including an interview 6 months before dying. We
analyzed self-reported mobility collected prospectively at
6-month intervals during the last 3 years of life. We
derived trajectories in two ways: by averaging decline
within decedent groups prespeciﬁed according to clinical
conditions and by estimating trajectory models using maxi-
mum-likelihood semiparametric modeling.
RESULTS: Ninety-eight percent of decedents were classi-
ﬁed according to 4 prespeciﬁed clinical conditions (sudden
death, terminal, organ failure, frailty), which produced
groups with different characteristics. Five disability trajec-
tories were identiﬁed: late decline, progressive disability,
moderate disability, early decline, and persistent disability.
Disability trajectory and clinical condition grouping con-
ﬁrmed previous research but were only marginally related.
CONCLUSION: Derived disability trajectories and group-
ing according to clinical condition provide useful informa-
tion about different facets of the end-of-life experience.
The lack of ﬁt between them suggests a need for greater
attention to heterogeneity in disability in the period before
death. J Am Geriatr Soc 2018.
Key words: end of life; trajectories; disability; mobility;
n the 1960s, sociologists Glaser and Strauss observed
people dying in a hospital setting and described different
trajectories of dying: abrupt, surprise deaths; expected
deaths (short- and long-term); and entry-reentry deaths.
graphical representation of these ideas was included in the
Institute of Medicine 1997 report Approaching Death,
and clinicians widely accepted the scheme as congruent
with their own experience. Our early research provided
empirical support for the classiﬁcation scheme,
recent work has challenged the usefulness of clinical
groupings using latent trajectory modeling of disability to
illustrate that the course of disability in the last year of life
does not follow a predictable pattern based on the condi-
tion leading to death.
We conducted a head-to-head com-
parison of the 2 approaches using the same data from a
single sample of decedents to determine the degree to
which previous ﬁndings were the result of approach rather
than decedent characteristics.
We derived our sample from the Health, Aging and Body
Composition (Health ABC) panel study. Participants were
recruited by mail in 1997–98 from a random sample of
From the *Hospital and Palliative Nurses Association;
Behavioral and Community Health Sciences;
Epidemiology, Graduate School of Public Health, University of Pittsburgh,
Department of Preventive Medicine, University
of Tennessee, Memphis, Tennessee; and
Laboratory of Epidemiology and
Population Sciences, National Institute on Aging, Bethesda, Maryland.
Suzanne Satterﬁeld is now deceased.
Address correspondence to June R. Lunney, 49 Ulverston Drive, Kennett
Square, PA 19348. E-mail: firstname.lastname@example.org
© 2018, Copyright the Authors
Journal compilation © 2018, The American Geriatrics Society 0002-8614/18/$15.00
death. J Am Geriatr Soc 66:503–508, 2018.
JAGS 66:503–508, 2018
2018, Copyright the Authors
2018, The American Geriatrics Society 0002-8614/18/$15.00