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| Journal of the New Zealand Medical Association,
19-June-2009, Vol 122 No 1297
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Not in my hospital? Ethnic disparities in quality of
hospital care in New Zealand: a narrative review of the evidence
Juliet M L Rumball-Smith
At the 2006 Census, 67.6% of the New Zealand population
self-identified as a member of the New Zealand European ethnic group, the second
largest ethnicity being NZ Māori (14.6%, total Māori ethnic
group).1 However as of 2000–2002, NZ
Māori men could expect to live on average 8 years less than a
non-Māori male.2
At all levels of deprivation, NZ Māori experience
greater rates of mortality than non-Māori, and a greater reduction in life
expectancy.3,4 Socioeconomic variables
contribute to these health outcomes inequalities, but are only one consideration
when investigating health differences between ethnic groups. Inequalities are
noted to persist after epidemiological control for these variables; this
phenomenon has been termed the ‘outcome
gap’.5
Why does this gap occur? Lalonde developed the Health Field
Concept to describe the broad and varied determinants of
health.6 Health status was conceptualised as
the result of a complex interplay between the biological characteristics of the
individual, lifestyle factors, the wider environment (including socioeconomic
factors), and the structure and actions of the health system.
It is possible that the health disparities between NZ
Māori and NZ Europeans may be contributed to by health services, including
the actions of those who work within it.7 There
is substantial evidence regarding health care disparities in other countries,
and despite differences in cultural and historical context, it is useful it is
useful to look at the findings of this international research.
The United States (US) has multiple minority populations,
totalling more than 100 million. There is a multitude of published studies
documenting ‘racial’ disparities in the quality of care in the US,
including several systematic reviews. The largest of the meta-analyses is
Unequal Treatment, a document produced by the Institute of Medicine at
the behest of US Congress, encompassing the review of more than 600 articles.
The Institute focussed on studies in which factors that impacted on the
patients’ financial ability to access treatment were controlled, potential
confounding variables were considered, and were those that compared the
appropriateness of services against established clinical guidelines.
The Institute concluded in its report that health
disparities according to race were ‘remarkably consistent across a range
of illness and health care services’ (p5). Although the investigators
found evidence for ethnic disparities in the receipt of quality care for
numerous conditions, the most significant evidence was demonstrated in
cardiovascular and cancer care, and in the care of patients with human
immunodeficiency virus.8
The evidence for disparities in the quality of care in the
US is so firmly established that the National HealthCare Disparity
report is produced annually to provide information regarding the progress of the
health system in providing equitable care to minorities.
There is a large amount of information available regarding
differences in health care use for NZ Māori as compared to non-Māori;
for example, NZ Māori have lower rates of access to some elective surgical
procedures, including angioplasty and major joint
replacements.9 However, do these differences
represent health care disparities?
Rathore and Krumholz propose five formal criteria against
which to assess racial differences, in order to ascertain if they may be
classified as ‘disparities’:10
They summarise these
concepts in their definition of disparity, stating that ‘a disparity in
health care use may be considered a difference in appropriate treatment
use that is associated with poorer clinical outcomes and is not
attributable to patient factors’ (p636). This statement clearly
relates health care inequality with health outcomes, and emphasises the need to
control for possible confounding and mediating factors. While their criteria
must be considered with caution (is differential treatment for those of
differing socioeconomic position acceptable?), the definition provides a useful
framework against which evidence may be assessed.
Considering the information above, it is theoretically
possible that NZ Māori actually receive the appropriate level of elective
surgical input, and non-Māori may over-use these services. Therefore, the
differences in care use represent disparities only if it can be demonstrated
that the level of care is inappropriate to the level of need, and that health
and well-being suffer as a consequence. Similarly, rates of use do not consider
the impact of patient factors; such as patient preference, severity of illness,
or impact of comorbidities on eligibility criteria.
This study aimed to review the evidence for disparities in
the quality of care received by NZ Māori within New Zealand. It is focussed
on the quality of care received at public hospitals, which is provided at no
financial charge to all New Zealand residents.
MethodsA literature review was conducted of Ovid databases
Medline (1950–2008 week 32) and Embase (1947–2008 week 32) using the
following search terms: ethnic$ or ethnicity, race$ or racial$, quality of
health care/, Māori, New Zealand, health status disparities/, minority
groups/, cross-cultural comparisons/.
This initial combination yielded only 49 studies.
Subsequently, the search was expanded to the combination of two separate
searches involving only two search terms each, quality of health care/ or ethnic
differences/ in combination with (New Zealand or Māori). New Zealand
researchers were also contacted to obtain unpublished ‘grey
literature’ pertaining to this topic. After applying limits regarding
English language, human, and availability of abstract, this strategy revealed
266 distinct publications. Studies were reviewed if they involved the assessment
of the quality of inpatient care, were set within the publicly-funded hospital
environment, and involved comparative analysis according to ethnicity.
The methodology of each study was assessed; reviewing
its design, data sources, study and comparison population, choice of indicators,
and consideration of potential confounders and sources of bias. Two criteria
were applied to ascertain whether findings from each study were indicative of a
healthcare ‘difference’ or a ‘disparity. These criteria were
borrowed from the definition advanced by Rathore and
Krumholz,10 as detailed above. That is, were
the findings of the studies examined that demonstrated healthcare quality
differences:
ResultsStudies that employed quality indicators that were specific
to inpatient care were few; totalling 11 only. These documents were varied, both
in the indicators employed, and in the clinical conditions examined.
Accordingly, it was not possible to conduct a formal systematic review, in which
the studies’ findings could be collated and quantitatively synthesised. A
narrative approach was considered to be more appropriate, being able to
encompass the diversity of the investigations and provide qualitative
conclusions.
The 11 studies varied in quality, some considering the
impact of multiple confounding factors, as well as potential statistical bias
from undercounting of Māori; others performing few methodological or
statistical adjustments for these factors.
The details of the investigations are noted in Table 1; and described further below, grouped according to
clinical condition:
Obstetric interventionStudies—Four of the 11 studies
considered outcomes related to obstetric intervention. Ministry of Health
documents note that Māori undergo lower rates of these procedures than
non-Māori;11–15 yet it has been
suggested that Māori may experience higher risk pregnancies than
non-Māori.11 Certainly, there is evidence
of greater rates of maternal diabetes and smoking during pregnancy in
Māori,16,17 both factors associated with a
higher risk of clinical intervention.
Johnson et al noted lower rates of caesarean section (CS)
and instrumental delivery in their cohort of Māori women at Middlemore
Hospital, yet these findings did not consider any potential confounding factors,
including age and parity.18
Sangalli and Guidera limited their population to nulliparous
women at term, and described no significant ethnic difference in the rate of CS
in their small sample (59 Māori women only) at Wellington Hospital,
although also performed minimal adjustment for other variables.
19
Sadler et al used information from a National Women’s
Hospital (NHW) database, 1992–1997. The study population was limited to
women without previous CS, who delivered a singleton following cephalic
presentation at NWH during the study period.20
Factors included in the modelling were age, parity, obstetric risk factors,
transfer of care, booking caregiver, and an indication of the chronicity of
their antenatal care using gestation at booking.
After adjustment for these variables, the Māori women
were significantly less likely to undergo induction of labour, pre-labour CS,
and operative vaginal delivery. The researchers note that the lower rates of
epidural analgesia may contribute to the lower rate of operative vaginal
delivery in Māori women (this factor was not included in the multivariate
analysis). However, the differences in rates described—despite control for
a significant number of possible variables- indicate that Māori in this
sample may have received disparate treatment.
Harris et al reviewed CS rates nationally, and noted similar
results. This team of researchers used the national hospital database to
identify women delivering by CS at public and private hospitals
1997–2001.21 They used the ‘Ever
Māori’ classification technique to minimise under-counting of
Māori, and obtained data regarding fetal presentation, gestation at
delivery, multiple births, maternal hypertension, diabetes, and antepartum
haemorrhage.
These clinical factors were included in the modelling, as
were deprivation (using NZDep96 deciles), age, DHB, and parity. Of nulliparous
women without previous CS, non-Māori were more likely to undergo acute,
elective, and any type of CS (all significant results). Similar significant odds
ratios were demonstrated in women regardless of parity.
Ethnic variation in obstetric intervention:
difference or disparity?—Obstetric and perinatal outcomes are
known to be poorer for Māori women and their babies compared to NZ European
patients.22 The studies by Sadler et al. and
Harris et al. provide evidence of ethnic health care disparities. Although the
differences in interventions are not directly linked to these health outcomes
(and it is possible that CS is ‘over-employed’ in non-Maori women),
their analyses consider the rate of services delivered in comparison to clinical
need. The two research teams also considered the impact of a large number of
demographic and clinical variables in the sampling strategies and statistical
techniques employed.
Preventable adverse eventsStudy—Davis et al conducted a
cross-sectional examination of the records of a stratified sample (according to
location and hospital type) of 6579 hospital patients across thirteen hospitals
throughout New Zealand.23 Records of all
patients admitted in the year 1998 were examined, excluding psychiatric,
rehabilitation-only, and day case admissions. Trained nurses examined the
clinical notes initially, to identify the occurrence if Adverse Events (AE),
defined as the ‘unintended injury that resulted in disability, with any
evidence of causation by health-care management rather than the underlying
disease’ (p1921).
Records in which an AE occurred were then subsequently
examined by medical practitioners, in order to confirm the AE and form a
judgment regarding its preventability; that is, to identify if there was
evidence of failure to follow accepted practice at a system or individual level.
After controlling or adjusting for age, deprivation,
admission type, length-of-stay, and sex, the researchers noted that the
incidence of in-hospital preventable AE for Māori was nearly 50% greater
than in the non-Māori non-Pacific sample (adjusted odds ratio 1.47).
This study used the ‘gold-standard’ of chart
review to ascertain the quality of care; however patients may still receive poor
quality of care that does not result in an AE. This lack of sensitivity is
common to many quality indicators, and requires consideration when interpreting
results. The study did not account for misclassification of Māori, however
numerator-denominator bias is unlikely to have a significant impact given the
comparisons were made internally within the cohort. However, this study did not
consider the impact of clinical factors such as severity of illness, clinical
condition, and comorbidities on the occurrence of AE; control of these variables
may assist in assessing the distinction between an ethnic healthcare
‘difference’ and ‘disparity’ in this context.
Ethnic variation in preventable adverse events:
difference or disparity?—The indicator used in this study is in
itself adverse health outcome, fulfilling one aspect of the definition by
Rathore and Krumholz. Although some patient variables were considered in the
statistical analyses, adjustment for clinical factors may assist in further
clarifying the association between ethnicity and incidence of preventable
adverse events. However, even without such information, this study provided some
evidence for ethnic disparity in the incidence of this indicator within the
hospital setting.
Rate of cardiac interventionsStudies—Two studies assessed the
comparative rates of coronary artery bypass graft (CABG) and percutaneous
transluminal cardiac angioplasty (PTCA) interventions at hospitals in New
Zealand, both employing the National Minimum Data Set.
Westbrooke et al compared the hospitalisation rates for
Māori with their rates of intervention 1996–2000), and noted a
discrepancy between apparent clinical need (demonstrated by excess
hospitalisation) and their access to these
interventions.24
The researchers adjusted or controlled for age, sex, and
deprivation, but did not include clinical variables such as comorbid conditions.
The results of statistical analyses were not quoted in this paper; as such it is
not possible to draw conclusions regarding the statistical significance of the
findings. However, it is probable that given the large sample size (more than
40,000), it is unlikely that differences of the magnitudes quoted would be due
to chance.
Tukuitonga et al similarly reviewed the rates of these
cardiac interventions performed at public and private hospitals
1990–1999.25 They noted that age-adjusted
intervention rates for CABG and PTCA for Māori men and women were
considerably lower than those for non-Māori.
The study compared these rates with that of age-standardised
mortality rates for coronary artery disease, and graphically demonstrated the
difference in the perceived clinical need of Māori compared to their
receipt of these interventions. Although the analyses did not control for other
demographic or clinical factors, the differences between the two groups were so
large that it is unlikely that consideration for these variables would have
significantly altered the observed association with ethnicity. This study
provides an indication of possible inequities in the delivery of these
interventions, although it is possible that other factors may play a role in the
apparent inverse care of Māori in this respect.
Ethnic variation in cardiac intervention: difference
or disparity?—These studies attempted to link health outcomes
with utilisation of services by comparing clinical need (using hospitalisation
and mortality rates) with access to intervention. After applying the criteria of
Rathore and Krumholz, the findings of the studies are indicative (but not
conclusive) of ethnic health care disparities in the rates of cardiac
interventions.
Treatment for end-stage renal diseaseStudies—Two studies used information
from the Australia and New Zealand Dialysis and Transplant Registry, assessing
the records of patients first treated for End-Stage Renal Disease (ESRD) at a
public hospital in Australia and New Zealand, to examine processes of care for
these patients.
McDonald and Russ assessed the records of those treated
during 1991–2000, noting the difference in the incidence of ESRD between
Māori and the non-indigenous population (New Zealand non-Māori
non-Pacific and Australian non-Aboriginal or Torres Strait
Islander).26
The authors noted that Māori were statistically
significantly less likely to be listed on the renal transplant waiting list than
the non-indigenous group, a difference that persisted after stratification for
age and sex although the adjusted ratios were not detailed. Indigenous people
were also less likely to receive a graft once accepted for transplantation,
although the OR calculated (0.35, 95% CI 0.29–0.43) also included Pacific
Islanders, Torres Strait Islanders, and Australian Aboriginals.
It is possible that genetic factors may play a role in the
receipt of transplants, as they also provided evidence of ‘poorer
matched’ grafts for the indigenous population. That is, sheer numerical
factors make it harder to find a donor for minority group patients. Factors such
as socioeconomic status, clinical severity and condition, and geographical
location were not included in the analysis.
Stewart et al selected 421 Māori patients and 1787
non-Māori non-Pacific New Zealanders from the same register, noting a
higher incidence and mortality from the disease in the Māori
group.27 While the authors noted that
Māori with glomerulonephritis were less likely to have undergone
histological examination of their kidneys, the differences in the proportions
noted were not subject to statistical testing, nor controlled for factors other
than age and sex.
However, the differences described are reminiscent of the
findings of Robson et al, who noted that Māori with cancer were less likely
to have staging information recorded on registration documents than
non-Māori. It is possible that these process indicators reflect disparities
in the care for Māori within hospitals.
Ethnic variation in the processes of care for
patients with ESRD: Difference or disparity?—It is possible that
the differences in these process indicators reflect disparities in the care for
Māori within hospitals. However, the indicators used are not linked to
health outcomes (although they were compared with incidence of ESRD), and there
was limited control or consideration of other variables in the two studies. As
such, these investigations describe ethnic health care differences, but do not
provide conclusive evidence of disparities in the quality of care for
Māori.
Outcomes post-tympanostomy tube insertionStudy—Allen et al reviewed
postoperative morbidity for Māori and non-Māori children who underwent
tympanostomy tube insertion over three months in
2001.28 Although they noted that Māori
were at greater risk of having a non-functioning tube post-operatively,
ethnicity was not assessed as an independent variable with other factors of
influence controlled.
Ethnic variation in quality of tympanostomy tube
insertion: difference or disparity?—This study demonstrates the
use of surgical health outcomes as indicators of the quality of care. However it
is possible that the small sample sizes involved (26 Māori, 54 Caucasian),
and the impact of unaccounted for clinical factors (such as ear condition at
time of surgery) and patient factors (such as compliance with medication
postoperatively and socioeconomic status) limit the interpretation of the
results of this investigation. As such, this study describes differences in
outcomes following this procedure within the study sample, but cannot provide
robust evidence of health care disparities for different ethnic groups.
Restrictive care practicesStudy—Kumar et al reviewed the care
of 125 Māori and 175 non-Māori mental health patients admitted to
Rotorua Hospital, 2000–2001.29 After
adjustment for age, sex, diagnosis, number of readmissions, and time of onset
between illness episode and admission, the researchers calculated odds ratios
for restrictive care practices. These were defined as including the use of
legislation for involuntary admissions, readmission rates, the use of restraint
and seclusion, and administration of higher doses of medication.
They noted that ethnicity was not associated with the first
three practices, but discovered that Māori patients were less likely to be
referred for psychotherapy, more likely to receive anti-psychotic medication,
and at higher doses. Given that diagnosis was controlled for in the analysis,
the authors concluded that Māori were more likely to receive
anti-psychotics for ‘non-psychotic diagnoses’, and that they did not
experience the same quality of care as non-Māori with regards to access to
psychotherapy.
Ethnic variation in processes of care for patients
with mental illness: difference or disparity?—The process of care
indicators employed in this study are not directly linked to health outcomes,
however it is logical that reduced access to psychotherapy may represent poor
quality of care. However, the administration of anti-psychotics is less
intuitive. While it is possible that Māori are being over-medicated, it is
also possible that Māori are being appropriately treated and that
non-Māori are being under-treated for mental illness in this hospital.
It would be helpful to be able to compare treatment regimes
with agreed clinical guidelines or discrete health outcomes. Without this
information, this study provides descriptive evidence of differences in the
management of some mental health patients; however it is unknown whether these
differences are disparities, and whether they represent poorer quality of care
for one ethnic group.
OtherThe review revealed several pieces of research that
investigated the quality of care using measures that reflected several facets of
the health system. Indicators such as avoidable or disease-specific mortality
reflect the performance of all sectors of the health system, including public
health, primary, secondary and tertiary care. The measures reflect the
effectiveness and coordination of care provided over prolonged periods of time,
and by multiple organisations and individuals. As such, it is not possible to
directly extrapolate the results of studies using these indicators to the
discrete performance of public hospitals.
However, the consistency of findings by multiple researchers
in the detection of healthcare disparities using these broad indicators warrants
mention. For example, studies using the following indicators have universally
demonstrated disparities for Māori: disease-specific
mortality,30-33 avoidable
hospitalisation,34,35 avoidable or amenable
mortality,7,36,37 involuntary psychiatric
admission, 38 and perception of unfair
treatment by a health professional.39
The evidence for disparities in cancer outcomes and
processes of care is particularly
significant.40,41 Although not assessed
directly in this study, it is important to note the differences in health
services received by Māori with cancer, despite statistical control for
stage at diagnosis, comorbidities, and socioeconomic variables.
42
DiscussionThe intention of this review was to assess literature
evidence for disparities in the quality of inpatient hospital care received by
Māori. This study has its limitations, primarily in the few available
studies and the probability of publication bias. The articles discussed in this
paper are varied, in most cases focussing on discrete clinical conditions, and
together they employ a variety of quality indicators. As such, it is not
possible to sum up their findings into one succinct conclusion. However, it is
worth noting the following points:
There is little information regarding the causes
of potential ethnic healthcare disparities in New Zealand, although Harris et
al. note that NZ Māori are more likely to perceive discrimination by health
professionals than non-Māori. 39 It is
likely that multiple factors contribute to healthcare disparities: The Institute
of Medicine considers that the actions of the health system, the patients, and
the providers themselves all have a role.8
New Zealand researchers are fortunate to have access to a
national hospital database, which contains a vast amount of variables that can
be combined in quantitative analyses. Although the quality of ethnicity
information within hospital systems may be improvable, attempts at assessing the
impact of healthcare disparities on the health outcomes for Māori should
still be made. There may also be a role for the development and validation of
Māori-specific quality indicators, as suggested by previous researchers.
44, 45
In conclusion, there is some evidence for disparities in the
quality of in-hospital care for Māori in New Zealand. As health
professionals, it is important to take ownership of this evidence, and use it as
a possible area for intervention, to work towards improving health outcomes for
Māori.
Competing interests: None known.
Author information: Juliet M L
Rumball-Smith: Research Fellow, Department of Public Health and General
Practice, University of Otago, Christchurch
Acknowledgements: I am grateful to the
Health Research Council of New Zealand for funding this project, as well as Dr
Phil Hider (University of Otago, Christchurch), Dr Diana Sarfati (University of
Otago, Wellington), Professor Tony Blakely (University of Otago, Wellington),
and Annabel Ahuriri-Driscoll (ESR, Christchurch) for supervisory support. I also
thank Suzanne Pitama (Māori/Indigenous Health Institute, Christchurch) and
Dr Cheryl Brunton (University of Otago, Christchurch), and the two anonymous
NZMJ reviewers for their supportive comments.
Correspondence: Dr Juliet Rumball-Smith,
Research Fellow, Department of Public Health & General Practice, University
of Otago, Christchurch, PO Box 4345, Christchurch, New Zealand. Fax: +64 (0)3
3643697;
email: juliet.rumball-smith@otago.ac.nz References:
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