RES E A R C H A R T I C L E Open Access
Frailty and post-operative outcomes in
older surgical patients: a systematic review
Hui-Shan Lin
*
, J. N. Watts, N. M. Peel and R. E. Hubbard
Abstract
Background: As the population ages, increasing numbers of older adults are undergoing surgery. Frailty is
prevalent in old er adults and may be a better predictor of post-operative morbidity and mortality than
chronological age. The aim of this review was to examine the impact of frailty on adverse outcomes in the ‘older
old’ and ‘oldest old’ surgical patients.
Methods: A systematic review was undertaken. Electronic databases from 2010 to 2015 were searched to identify
articles which evaluated the relationship between frailty and post-operat ive outcomes in surgical populations with a
mean age of 75 and older. Articles were excluded if they were in non-English languages or if frailty was measured
using a single marker only. Demographic data, type of surgery performed, frailty measure and impact of frailty on
adverse outcomes were extracted from the selected studies. Quality of the studies and risk of bias was assessed by
the Epidemiological Appraisal Instrument.
Results: Twenty-three studies were selected for the review and they were assessed as medium to high quality. The
mean age ranged from 75 to 87 years, and included patients undergoing cardiac, oncological, general, vascular and
hip fracture surgeries. There were 21 different instruments used to measure frailty. Regardless of how frailty was
measured, the strongest evidence in terms of numbers of studies, consistency of results and study quality was for
associations between frailty and increased mortality at 30 days, 90 days and one year follow-up, post-operative
complications and length of stay. A small number of studies reported on discharge to institutional care, functional
decline and lower quality of life after surgery, and also found a significant association with frailty.
Conclusion: There was strong evidence that frailty in older-old and oldest-old surgical patients predicts post-
operative mortality, complications, and prolonged length of stay. Frailty assessment may be a valuable tool in peri-
operative assessment. It is possible that different frailty tools are best suited for different acuity and type of surgical
patients. The association between frailty and return to pre-morbid function, discharge destination, and quality of life
after surgery warrants further research.
Keywords: Post-operative complications, Mortality, Geriatric, Oldest old, Frailty
Abbreviations: FI, Frailty index; CSHA, Canadian Study of Health and Aging; EAI, Epidemiological appraisal
instrument; CGA, Comprehensive geriatric assessment; MACCE, Major cardiac and cerebral adverse events
* Correspondence: huishan.lin@uq.net.au
Centre for Research in Geriatric Medicine, Princess Alexandra Hospital, The
University of Queensland, Level 2, Building 33, Ipswich Road,
Woolloongabba, QLD 4102, Australia
© 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Lin et al. BMC Geriatrics (2016) 16:157
DOI 10.1186/s12877-016-0329-8
Background
As the population ages, the rate of surgical procedures
in the older population is rising. In England, 2.5 million
people over the age of 75 years underwent surgery be-
tween years 2014 and 2015, as opposed to just under 1.5
million between 2006 and 2007 [1, 2]. Ne arly 30 % of
these 2.5 million were over 85 years old [1]. Similarly,
women aged 85 years and over now represent the largest
proportion in emergency surgical admissions in Australia
compared with all other age and sex groups [3].
It has long been recognised that advanced age can
carry increased risk of mortality and morbidity after sur-
gery. However, new knowle dge is emerging that frailty,
an age-related cumulative decline in multiple physio-
logical systems, is a better predictor of mortality and
morbidity than chronological age [4, 5]. Patients of the
same age do not all have the same risk. The identifica-
tion and assessment of frailty may facilitate identification
of vulnerable surgical patients so that appropriate surgi-
cal and anaesthetic management can be implemented.
Experienced clinicians may feel that they can identify
frailty by end-of-bed ‘gestalt’ assessments. However, ‘eye-
balling’ is subjective and tends to be inconsistent be-
tween different observers [6]. Currently there is no
standardised method of measuring frailty, with more
than 20 different frailty instruments identified in a sys-
tematic review [7]. These different scales are based on
the two main models which characterise how frailty de-
velops and manifests. In the 'phenotype’ model described
by Fried et al. [8], frailty manifests as decline in lean
body mass, strength, endurance, balance, walking per-
formance and low activity. Patients who have three or
more of the five features of slowness, weakness, exhaus-
tion, weight loss and low physical activity are deemed
frail, while those who have none of the features are non-
frail. Patients who display one or two of the five features
are “pre-frail” [8].
The second model by Rockwood et al. is the Frailty
Index (FI), or the cumulative deficit model, developed in
the Canadian Study of Health and Aging (CSHA) [9].
This model conceptualises aging as the accumulation of
deficits and views frailty as a multidimensional risk state
quantified by the number of deficits rather than by the
nature of the health problems. An FI can be based on
comprehensive geriatric assessment and is calculated by
counting the number of deficits present in an individual,
divided by the total number of deficits measured [10].
The deficits encompass co-morbidities, physical and
cognitive impairments, psychosocial risk factors and
common geriatric syndromes [10]. The FI score ranges
between 0 and 1, with higher scores indicating greater de-
gree of frailty. FI represents a continuum; however, it can
also be trichotomised to indicate low, intermediate and
high level of frailty (FI ≤ 0.25, FI >0.25-0.4, FI >0.4) [11].
There has been a significant increase in literature over
the last five years on the subject of frailty in surgical pa-
tients. A search for articles on Pubmed published be-
tween the years 2011 and 2015 using search terms
‘frailty’ AND ‘surgical outcome’ identified 173 titles,
whereas the same search for publications between 2006
and 2010 yielded only 34 titles. The majority of the
current literature investigating frailty and surgery has
defined ‘geriatric’ as those above 60 or 65 years old.
However, there has been a change in who is thought of
as ‘old’. Basing studies on someone 65 years old may not
provide insight into appropriate treatment for the ‘new’
geriatric patient [12]. Despite frailty being more preva-
lent with increasing age, and the large proportion of
those over 75 years old undergoing surgery, frailty in the
‘old old’ and the ‘oldest old’ (aged 75–85 and over
85 years) surgical patients has been less comprehensively
explored.
The aim of this systematic review, therefore, was to
examine the association between frailty and adverse
post-surgical outcomes in patients aged 75 years and
over.
Methods
Search strategy
PUBMED, MEDL INE, EMBASE and Cochrane online
databases were searched using search terms of ‘frail*’
AND ‘surg*’ in combination with (‘outcome’ OR ‘mor-
bidity’ OR ‘complication’). An asterisk was used to indi-
cate the term was truncated or had a variation in
spelling. The search was conducted between October
and December 2015 with filters applie d to limit results
to the English language, human research, and publica-
tions from year 2010 and onwards.
Publication selection
The inclusion criteria for the search were: 1) the mean
participant age was over 75 years; 2) the patient popula-
tion had a surgical procedure; 3) frailty was assessed as a
composite measure of more than one domain of health
deficit, which accords with the current conceptualisation
of frailty [13, 14] and was the main factor of interest in
the study; and 4) the relationship between frailty and ad-
verse outcomes was evaluated. Exclusion criteria were
review articles, conference abstracts, and studies which
measured frailty as a single item, such as a scan finding,
a blood marker, or a physical performance test such as
gait speed.
Data extraction
Two reviewers (HL, JW) conducted the searches inde-
pendently and compared results after assessing all iden-
tified abstracts for their compliance with the review
criteria. Where agreement could not be reached a third
Lin et al. BMC Geriatrics (2016) 16:157 Page 2 of 12
independent reviewer (NP) was consulted. Reasons for
exclusion were documented.
The follo wing data were extracted from the eligible
studies: sample size, mean age, country of origin of the
study population, study design, type of surgery per-
formed, frailty measure, and impact of frailty on adverse
outcome.
Assessment of study quality and risk of bias
Two reviewers (HL, JW) independently assessed the
quality of the included studies using a modified version
of the Epidemiological Appraisal Instrument (EAI), a
valid and reliable tool for rating the quality of observa-
tional studies [15]. The EAI checklist addressed the fol-
lowing five domains of risk of bias: reporting, subject
selection, measurement quality, data analysis, and gener-
alisation of results. Each of the 23 questions in the EAI
applicable to the selected studies was scored a s yes (=2),
partial (=1), no or unable to determine (=0) with the
highest possible score being 46.
An a priori decision was made to divide the total pos-
sible score into quartiles. Quartile 1 (Q1) was 35–46
(the highest quality), quartile 2 (Q2) was 23–34, quartile
3 (Q3) was 12–23 and quartile 4 (Q4) wa s 0–11 (the
lowest quality). Any disagreement regarding the assess-
ment of the quality of a study was resolved by consulting
a third reviewer (NP).
Grading the overall strength of the evidence
The overall strength of the evidence was evaluated using
principles outlined by the Agency for Healthcare Re-
search and Quality [16]. The key elements of evaluation
were quality (based on study design according to the
hierarchy of evidence and study execution), quantity
(based on the number of studies) and consistency.
Results
The literature search identified 686 articles (187 from
Pubmed, 169 from Medline, 300 from Embase and 28
from the Cochrane database). From these, 270 duplicate
articles were removed. The titles, abst racts and the full
texts of the articles were reviewed. Articles were selected
based on inclusion and exclusion criteria. The references
of selected articles were hand searched for further eli-
gible articles. There were 23 articles included in the final
analysis. The study selection process as well as the rea-
sons for exclusion are shown in Fig. 1.
In the 23 articles selected for this review, there were
16 cohorts of patients with a mean or median age ran-
ging from 75 to 87 years. Twenty studies were of pro-
spective design with sample sizes ranging from 30 to
450 [17–36], and three were of retrospective design
[37–39], one of which contained a large sample size of
nearly 13,000 participants [37]. Publications came from
different countries, including USA [17, 18, 35, 37–39], UK
686 records identified through
database searching.
416 records screened
320 records excluded
on title or abstract
96 full-text articles
assessed for eligibility
73 full-text articles excluded
39 mean age not defined or
under 75 years old
2 not in English language
2 analysis included participants
who did not have surgery
20 frailty measured using single
domain or no composite
measure use
9 main outcome interest was
not the relationship between
frailty and adverse outcome
1 commentary
23 studies included in
current review
270 duplicates
removed
0 additional records identified
through other sources
ScreeningEligibility
Included
Identification
Fig. 1 PRISMA flow diagram for study selection
Lin et al. BMC Geriatrics (2016) 16:157 Page 3 of 12
[30, 32, 34, 36], Europe [19–28, 31], and Asia [29, 33]. The
proportion of females ranged from 31 % [34] to 83 % [35].
Five studies did not report the gender distribution of the
cohorts [22, 23, 29, 32, 38]. A meta-analysis was not con-
ducted due to a lack of homogeneity of frailty measures
and the diversity of surgical procedures.
Nine studies measured frailty in cardiac surgery
[17–24, 39], six in oncological surgery (predominantly
focusing on colorectal cancer ) [25–29, 37], three in gen-
eral surgery [30, 31, 33], three in hip fracture surgery
[35, 36, 38] and two in vascular surgery [32, 34]. Sixteen
articles involved participants undergoing elective surgery
[17–29, 33, 37, 39], five involved those undergoing acute
surgery [30, 31, 35, 36, 38], while two included those
undergoing both elective and acute surgery [32, 34].
Table 1, grouped by the type of surg ery, describes the
demographics, measurement of frailty and adverse out-
come predicted by frailty for the selected studies.
Study quality and risk of bias
The EAI scores of the 23 studies ranged from 31 to 45, in-
dicating they were in the upper two quartiles of study
methodological quality. The EAI scores were in the in the
second quartile for eight studies [18, 19, 22–24, 28, 29, 32]
while the remainder 15 studies were in the first quar-
tile [1 7, 20, 21, 25–27, 30, 31, 33–39]. There was a
high level o f agreement o f quality assessment between
the t wo independen t re viewers. The most poorly re-
ported items across all studies were: sample size cal-
culation, adjustment for covariates and t he report of
losses to follow up. Study quality scores are incorpo-
rated into Table 2.
Frailty instruments
Ofthe23includedstudies,21differentinstruments
were used to measure frailty. Variations of the Fried
Criteria or instruments based on Comprehensive
Geriatric Assessment (CGA), including the Frailty
Index, were used in the majority of studies. S cales
based on CGA are obtainable from p atient interview
as we ll as clinical notes without physical performance
based measures, and were used in both acute and
elective surgical cohorts. In contrast , the Fried frailty
measure required physical performance-based tests ,
and was used exclusively in elective surgical cohorts.
Four instruments, such as Multidimensional Frailty
Score [33] and Comprehensive Assessment of Frailty
[22–24], combined aspe ct s of CGA with performance
based test s (e.g. balan ce a ssessments , chair rise, stair
climb) and medical investigations (e.g. blood te st and
respiratory function test). Details of measurement of
frailty are presented in Table 1.
Adverse outcomes predicted by frailty
Table 2 shows the adverse outcomes associated with
frailty, grouped by the quality of the studies. Short, inter-
mediate and long term mortality were assessed by 16 pa-
pers. Of ten studies evaluating the relationship between
frailty and 12 month mortality, all found a significant re-
lationship with frailty [18, 19, 21, 23, 24, 32, 33, 37–39].
Odds Ratios ranged between 1.1 and 4.97 for the frail
patients compared with those who were non-frail
[18, 21, 23, 24, 38, 39]. This association was found re-
gardless of the instruments used to measure frailty and
irrespective of the type of surgery performed.
In the two papers that assessed long term mortality,
frailty was associated with increased two year mor tality
with an Odds Ratio of 4.01 [38] and increased five year
mortality with an Odds Ratio of 3.6 [27]. The association
between frailty and 90 day mortality wa s evaluated in
two studies [30, 37]. One found a significant association
with an Odds Ratio of 10.4 [37] while the other did not
find a significant assoc iation [30]. Thirty day mortality
was evaluated in six studies [21, 22, 26, 30, 31, 36]; all
but one [30] found a significant association, with Odds
Ratios ranging between 1.4 and 8.3 3 [21, 26, 31]. This
latter study included only a small proportion (31 %, n =
105) of patients who underwent surgery [30].
Post-operative complications, as graded by the
Clavian-Dindo severity classification [40] or pre-
defined by the authors, were evaluated in nine papers
[17, 18, 25, 29, 31, 33–35, 39]. Frailty was associated
with increased post-operative complications in four
studies with Odds Ratios ranging from 1.5 to 4.8 [18, 25,
29, 31]. The remaining five studies repor ted no signifi-
cant association [17, 33–35, 39]. The definitions used for
post-operative complications in these 10 studies were
heterogeneous. Conditions pre-specif ied in the studies
which counted as a post-operative complication included
cardiac complications (namely myocardial infarction,
heart failure, arrhythmia), pulmonary embolism, pneu-
monia , wound infection, major bleeding, renal failure,
delirium, unplanned return to theatre and unplanned in-
tensive care unit admis sion.
Specific items of post-operative complications were
also examined by several studies. An association between
frailty and major cardiac and cerebral adverse events
(MACCE) was reported by one of the three studies
evaluating this outcome [19, 21, 23]. One study explored
the association between frailty and delirium and did not
find a significant association [35]. Of two studies evalu-
ating frailty and readmission rate, one study found a sig-
nificant association [32] while the other did not [30].
One study showed a significant association between
frailty and the need for resuscitation [23].
Of the six studies that included prolonged length of
stay as an outcome, an association with frailty was found
Lin et al. BMC Geriatrics (2016) 16:157 Page 4 of 12
Table 1 Study demographics grouped by type of surgery
Author Sample size
Country of origin
Mean or median age
% female
Study design
Type of surgery Frailty measure Adverse outcome predicted by frailty Association between frailty and
adverse outcomes
Cardiac
Afilalo, J et al. [17]
a
152
USA,
Canada
Mean age 75.9
34 % female
Prospective cohort study
Cardiac surgery
(Elective)
Fried criteria (or Cardiovascular
Health Study frailty scale)
Modified CHS frailty scale
Fried + cognitive impairment +
depressed mood
4-item MSSA frailty scale
gait speed, handgrip strength,
inactivity, cognitive impairment
Gait speed
Composite end point of post-
operative mortality or major
morbidity
Fried criteria, non-sig
Modified CHS frailty scale, non-sig
4 item MSSA frailty scale, non-sig
Gait speed, OR 2.63 (p < 0.05)
Green, P et al. [39]
a
244
USA
Median age, %female
- frail 87.1,53 %
- non-frail 85.4,45 %
Post-hoc analysis of
PARTNER trial
Transcatheter Aortic
Valve Replacement
(TAVR)
(Elective)
Fried criteria condensed into 4
domains
gait speed, grip strength, serum
albumin, Katz index of ADL
Frail ≥6/12
1) Adverse clinical events at 30 days
2) 1 year mortality
3) Poor outcome (composite mortality
& QoL assessed by KCCQ-OS)
a) 6 months
b) 1 year
Adjusted for covariates
1) non-sig
2) OR 2.5 (p = 0.0002)
3)
a) OR 2.21 (p = 0.03)
b) OR 2.4 (p = 0.02)
Green, P. et al. [18]
b
159
USA
Mean age 86
50 % female
Prospective cohort study
Transcatheter aortic valve
replacement, (TAVR)
(Elective)
Fried criteria condensed into 4
domains
gait speed, grip strength, serum
albumin, Katz index of ADL
Frail >5/12
1) 1 year mortality
2) LOS
3) Procedural outcomes (any of
major bleeding event, major vascular
complications, stroke, acute kidney
injury, 30 day mortality)
Adjusted for covariates
1) OR 3.5 (p = 0.006)
2) 9 vs 6 days (p = 0.004)
3) OR 2.2 (p = 0.04) for major bleeding
but not other adverse outcomes
Kamga, M et al. [19]
b
30
Belgium
Mean age 86
47 % female
Prospective cohort study
TAVI
(Elective)
Score Hospitalier d'Evaluation du
Risque de Perte d'Autonomie
(SHERPA-risk of functional decline)
score
MMSE, age, perceived poor health, fall
in the last year, number of iADL
independently performed before
admission
Identification of Seniors at Risk (ISAR)
score
>3 medications, self reported memory
problems, sensory problems, hospital
admission within the last 6 months,
increased need for help at home
1) 1 year mortality
2) Major cardiac and cerebral
adverse events (MACCE)
Adjusted for covariates
1) SHERPA HR2.74 for every 1 point
increase in score
(p = 0.004)
ISAR non-sig
2) SHERPA non-sig
ISAR non-sig
Schoenenberger,
A.W. et al. [20]
a
119
Switzerland
Mean age 83.4
55.5 % female
Prospective cohort study
TAVI
(Elective)
Mini Mental State Exam, Mini
Nutritional Assessment, TUG, BADL,
IADL, pre-clinical mobility disability
Frail ≥3
1) Functional decline (BADL ↓ ≥1
point)
2) Functional decline or death
among all participants at 6 months
Univariate
1) OR 3.31 (p = 0.02)
2) OR 4.46 (p = 0.001)
Lin et al. BMC Geriatrics (2016) 16:157 Page 5 of 12