BACKGROUND: Cardiovascular disease (CVD) is responsible for the largest number of discharges against medical advice (AMA). However, there is limited information regarding the reasons for discharges AMA in the CVD setting. OBJECTIVE: To identify reasons for discharges AMA among patients with CVD. DESIGN: Qualitative study using focus group interviews (FGIs). PARTICIPANTS: A convenience sample of patients with a CVD-related discharge diagnosis who left AMA and providers (physicians, nurses and social workers) whose patients have left AMA. PRIMARY AND SECONDARY OUTCOMES: To identify patients' reasons for discharges AMA as identified by patients and providers. To identify strategies to reduce discharges AMA. APPROACH: FGIs were grouped according to patients, physicians and nurses/social workers. A content analysis was performed independently by three coauthors to identify the nature and range of the participants' viewpoints on the reasons for discharges AMA. The content analysis involved specific categories of reasons as motivated by the Health Belief Model as well as reasons (ie, themes) that emerged from the interview data. RESULTS: 9 patients, 10 physicians and 23 nurses/social workers were recruited for the FGIs. Patients and providers reported the same three reasons for discharges AMA: (1) patient's preference for their own doctor, (2) long wait time and (3) factors outside the hospital. Patients identified an unmet expectation to be involved in setting the treatment plan as a reason to leave AMA. Participants identified improved communication as a solution for reducing discharges AMA. CONCLUSIONS: Patients wanted more involvement in their care, exhibited a strong preference for their own primary physician, felt that they spent a long time waiting in the hospital and were motivated to leave AMA by factors outside the hospital. Providers identified similar reasons except the patients' desire for involvement. Additional research is needed to determine the applicability of results in broader patient and provider populations.
BACKGROUND:Cardiovascular disease (CVD) is responsible for the largest number of discharges against medical advice (AMA). However, there is limited information regarding the reasons for discharges AMA in the CVD setting. OBJECTIVE: To identify reasons for discharges AMA among patients with CVD. DESIGN: Qualitative study using focus group interviews (FGIs). PARTICIPANTS: A convenience sample of patients with a CVD-related discharge diagnosis who left AMA and providers (physicians, nurses and social workers) whose patients have left AMA. PRIMARY AND SECONDARY OUTCOMES: To identify patients' reasons for discharges AMA as identified by patients and providers. To identify strategies to reduce discharges AMA. APPROACH: FGIs were grouped according to patients, physicians and nurses/social workers. A content analysis was performed independently by three coauthors to identify the nature and range of the participants' viewpoints on the reasons for discharges AMA. The content analysis involved specific categories of reasons as motivated by the Health Belief Model as well as reasons (ie, themes) that emerged from the interview data. RESULTS: 9 patients, 10 physicians and 23 nurses/social workers were recruited for the FGIs. Patients and providers reported the same three reasons for discharges AMA: (1) patient's preference for their own doctor, (2) long wait time and (3) factors outside the hospital. Patients identified an unmet expectation to be involved in setting the treatment plan as a reason to leave AMA. Participants identified improved communication as a solution for reducing discharges AMA. CONCLUSIONS:Patients wanted more involvement in their care, exhibited a strong preference for their own primary physician, felt that they spent a long time waiting in the hospital and were motivated to leave AMA by factors outside the hospital. Providers identified similar reasons except the patients' desire for involvement. Additional research is needed to determine the applicability of results in broader patient and provider populations.
Cardiovascular disease (CVD) is the leading cause of hospitalisations in the USA,1 with an estimated direct and indirect cost of
$503.2 billion in 2010.2 In 2006, the
number of discharges with heart disease as the first-listed diagnosis was 4.2
million.3 However, a proportion of these CVD
discharges were against medical advice (AMA), whereby the patient decides to leave the
hospital before the discharge has been authorised by the patient's
physician.4 National inpatient data from the
Healthcare Cost and Utilisation Project Nationwide Inpatient Sample show that diseases
of the circulatory system rank first among major diagnostic categories in terms of the
number of discharges AMA.5Recently, the policy focus regarding cost containment and quality improvement has
shifted to hospital readmissions. Medicare Administrative Contractors have recently
begun informing hospitals that any readmission occurring within 30 days of an
acute stay discharge is subject to review and referral to the quality improvement
organisation, with a possible payment denial for the second admission, the initial
admission or both.6 President Obama's 2010
budget singled out hospital readmissions as the largest source of waste in the American
healthcare system and called for initiatives that would save $26 billion over
10 years.6 Discharges AMA in a CVD
sample have been demonstrated to be associated with a higher likelihood of hospital
readmission for CVD.7Discharges AMA associated with CVD as well as readmissions resulting from these
discharges AMA could be impacted by targeted interventions designed to reduce discharges
AMA. However, the design of effective interventions depends on the identification of
reasons for discharges AMA.4 In the clinical
setting, identifying the reasons for discharges AMA from both patients' and
providers' perspectives provides information that can be used to foster shared
decision-making8 around the hospital stay,
which, in turn, supports8 the delivery of
patient-centred care. Patient centred care is defined as care that ‘is respectful
of and responsive to individual patient preferences, needs and values’ and that
ensures ‘that patient values guide all clinical decisions’.9 Shared decision-making around the treatment plan,
including the hospital discharge time, requires input from both the provider and the
patient. Thus, it is important to identify reasons for discharges AMA and from both
patients' and providers' perspectives.Reasons for discharges AMA in a general inpatient population,10
11 among patients with asthma12 and among patients with a history of psychiatric
conditions, drug or alcohol abuse have been identified.13–15 The reasons identified in a general inpatient
population and among patients with asthma include (1) drug addiction, (2) pain
management, (3) external obligations, (4) wait time, (5) dissatisfaction with care, (6)
teaching hospital setting, (7) communication and (8) feeling better.10–12 Factors associated with
discharges AMA also have been identified among patients with mental illness or substance
abuse and include: young age, single marital status, male gender, comorbid diagnosis of
personality or substance use disorders, pessimistic attitudes towards treatment,
disruptive behaviour, history of discharges AMA, sickness or death in the family,
financial problems, legal issues, provider's failure to orient patients to
hospitalisation and failure to establish a supportive provider–patient
relationship.13–15It is not clear to what extent prior findings would translate to a CVD setting, where
decision-making could be considered to be relatively more deliberate compared with the
broader population of patients who leave AMA, in which mental illness or substance abuse
can be more prevalent and could impact decision-making. In order to develop effective
interventions that also target discharges AMA in a CVD setting, the reasons applicable
to this specific patient population must first be identified. The objective of this
qualitative study was to identify reasons for discharges AMA among patients with a CVD
admission from the patient's and provider's perspective.
Methods
Participants
Focus group interviews (FGIs) were conducted to explore why patients left AMA
following a CVD-related hospitalisation. A convenience sample of patients
hospitalised for CVD who left AMA and healthcare providers who treated patients
requiring CVD-related care during their inpatient stay were recruited at three area
hospitals in Maryland between April 2009 and July 2009. Two patient FGIs, two
physician FGIs and three nurse/social worker FGIs were conducted. Patients,
physicians and nurses/social workers were interviewed separately in order to
facilitate a more candid discussion and reduce social desirability bias as it applies
to patients discussing situations that implicate providers, and providers (eg,
physicians) discussing situations that implicate patients or other providers (eg,
nurses). The study was approved by the University of Maryland Baltimore Institutional
Review Board, the Bon Secours Hospital Institutional Review Board and the MedStar
Office of Research Integrity.Patient inclusion criteria required a discharge AMA between 1 July 2006 and 30 June
2008, with a primary admitting diagnosis of CVD (The International Classification of
Diseases, 9th Revision, Clinical Modification (ICD-9-CM): 390–459). To reduce
the likelihood that patients required detoxification or psychiatric services,
patients with a non-primary admitting diagnosis of alcohol abuse (ICD-9: 265.2,
291.1–291.3, 291.5–291.9, 303.0, 303.9, 357.5, 425.5, 535.3,
571.0–571.1, 980.x, V11.3), drug abuse (ICD-9: 292.x, 304.x,
305.2–305.9, V65.42) or psychoses (ICD-9: 293.8, 295.x, 296.04, 296.44,
296.54, 297.x, 298.x) were excluded. In addition, patient discharge records with no
home address and invalid phone numbers, as well as non-Maryland residents were
excluded.Participant recruitment to the patient FGI was based on an initial invitation letter
sent via mail. The objective was to conduct one patient FGI at each of the three
participating hospital sites, with a targeted recruitment of 10 patients per FGI for
a total of 30 patients. Until we reached a sufficient number of positive responses
(ie, 30 positive responses), a follow-up telephone call was made after 1 week
of non-response to the initial invitation letter. Clinical directors at the
corresponding hospitals contacted healthcare providers (ie, physicians, nurses and
social workers) experienced with patients leaving AMA to inform them about the FGI. A
$50 honorarium for each participant was set using the wage-payment model.16
Conducting the focus groups
The methodological framework to develop a topic guide was based on the cognitive
constructs (perceived susceptibility to health consequences due to discharges AMA,
perceived severity of health consequences due to discharges AMA, benefits and costs
of discharges AMA) of the Health Belief Model.17 This topic guide was reviewed by clinicians (ES and MRW), a hospital
administrator and a health services researcher trained in qualitative analysis (FGP)
and was modified as needed to direct the conversation.Each FGI lasted approximately 1 h. The provider FGIs were held in a convenient
hospital location, and the patient interviews were held at facilities outside the
hospitals to minimise patient discomfort, given the interview topic. The same
moderator (EO) guided all FGIs. Two research assistants attended each FGI. All
participants were informed that the discussion would be audio-recorded and that the
transcriptions would be anonymous and confidential. Each participant verbally agreed
to these conditions.
Analysis
The recordings were manually transcribed by MZ. Each transcription was subject to an
additional review for accuracy by EO and EL. The associated audiotapes were
subsequently destroyed. A content analysis was performed in order to identify the
nature and range of the participants' attitudes. The content analysis involved
the research questions motivating the study (ie, to produce enquiry-driven categories
of the reasons for discharges AMA as informed by the application of the Health Belief
Model) as well as themes that emerged from interview data (ie, to produce thematic
categories). Within the context of patient, physician and nurse/social worker FGIs, a
complex thematic analysis18 was conducted
through immersion in the interview transcriptions to produce inductively identified
emergent themes. The content analysis was performed independently by EO, MZ and EL.
They compared and condensed their findings into a final analysis report. The
researchers were not necessarily searching for convergence in opinions and were just
as interested in identifying dissenting opinions. Key concepts were reported through
narrative and the use of participants' quotes. Quotes were selected for their
relevance and representativeness of the final selected themes, as identified based on
thematic- and enquiry-driven categories. Themes were identified separately for the
patient groups, the physician groups and the combined nurse and social worker
groups.
Results
A total of 120 patients meeting the inclusion and exclusion criteria were contacted by
invitation letter. Twenty-seven envelopes were returned due to invalid address, and 63
patients did not respond to the letter. A total of 30 patients responded either to the
invitation letter or to the follow-up telephone call. Nineteen patients were placed in
scheduled FGIs, with a final participation count of nine patients: seven men, six
African-Americans, with mean age of 56 years. A total of 10 physicians (eight
men) and 23 nurses/social workers (two men) were placed in scheduled FGIs consisting of
two physician-only groups and three nurse/social worker-only groups.
Reasons for discharges AMA
Figure 1 summarises the reasons for discharges
AMA among patients with CVD. Three themes were identified across the three types of
FGIs (ie, patient-only, physician-only and nurses/social workers-only).
Figure 1
Patient-reported and provider-perceived reasons for discharges against medical
advice following a hospitalisation due to cardiovascular disease.
Patient-reported and provider-perceived reasons for discharges against medical
advice following a hospitalisation due to cardiovascular disease.
Patient's preference for their own physician/specialist
The patient's lack of access to their own physician or cardiologist during
the inpatient stay was identified by patients and providers as a perceived barrier
to completing their course of treatment.Patient (PT): “So he said ‘I'll send you to my heart
doctor’, and I said I don't want to go to your heart doctor
because I got a specialist myself right in this same hospital. He said
‘I'm not going to discharge you’, and I said…
‘I'm going to go out of here. If that's the way it has
to be, I will sign myself out.’ ”Doctor (MD): “…She had a cardiologist at [Hospital 1], there
have been multiple times where the [Emergency Medical Services] brought her
[to Hospital 2] because they directed all the ambulance to [Hospital
2],…she was not happy that she was brought to [Hospital 2] in the
first place, she had been asking ER [emergency room] doctors to be
transferred out to [Hospital 1]. She gave everyone the cardiologist's
number, but they were unable to reach the cardiologist. Finally the patient
came up to the floor…I explained we tried to call. It was in the
middle of the night, so she called her family member and she left
AMA.”Nurse/social worker (RN/SW): “One of the things that I see is that
patients frequently have other care systems in place and have come here
because their hospital of choice is on red, or they were visiting and
admitted here emergently and their home hospital is a medical facility, or
their physician is not on staff and won't be following them here, and
they have an ongoing relationship with another provider…. and they
want to get back to that provider system.”
Long waiting time
Patients and providers identified experiencing a long waiting time as a reason for
discharges AMA in the CVD population.PT: “I laid there for two hours. Nobody came to give me an EKG. It
was like they were ignoring me…After I had laid there for about two
hours, the pain had stopped,…so I got up and I was
leaving.”MD: “Long wait time in the ER. If we're waiting for a bed to
open up, even if they have already been admitted they have already been
there for a couple of hours. And then when you go admit them and you do all
the work and everything's ready for them to be transferred up to a
bed, however the bed is not clean or available and they have to stay in the
ER and wait. A lot of patients don't like sitting in the ER waiting
for a room to open up as well.”RN/SW: “You do have patients that have not been seen for 10, 11 h by
a doctor.”“Timeliness I think it's a frustration, as we discussed,
length of stay…whether it's having the test ordered, done on
the same day, results in a timely manner, so that they're not waiting
all day.”
Factors outside the hospital
One barrier to completing the course of treatment identified by both patients and
doctors was having ‘something more important to do.’ These
activities included taking care of children at home, collecting a pay cheque and
paying rent.PT: “Just one particular time when I signed out, it's because
when I came it was the middle of the night, I had to pick up my grandson and
I drove myself here and I needed to put my car up so it wouldn't get
towed away, and make sure that my grandson was gonna be picked up properly.
And I signed myself out, took care of that business, and came
back.”MD: “Some of them get their checks, I think it's on the first
day of the month. I'm not sure. So you tend to see on the first day
of the month a lot of them are going to leave.”“I think in the last six to eight months I've seen a lot of
more people who are worried about jobs and cannot stay in the hospital
because they will lose their jobs.”RN/SW: “For instance I had a patient who [was admitted for] chest
pain….But there is some situation she wants to leave, like she came
here at evening time and the doctor wants her to stay here. …She
said, ‘My friend told me that he will not stay with my kids, if I
don't go home, the social service will come and take my
children.’ ”“Things are not okay at home for them to be in the hospital. So they
give it a day or so, and then, ‘I have to get out of here because I
have children at home, I have this going on, nobody can pick my children up
from school’ or they can't even go to school, so they just
can't stay.”“Actually it's a survival reason for a lot of people. Because
they know if they don't pay the rent right now, they're going
to get evicted.”
Other reasons
One reason was identified by the patient focus groups but not by the physician or
nurse/social worker focus groups. Patients identified an unmet expectation to be
involved in decision-making (eg, setting the treatment plan) as a reason to
discharge AMA. There were a few reasons identified only by the physician focus
groups and not by either patient or nurse/social worker focus groups. These
reasons included practice variability and nurses' attitude to patients.
Solutions
Participants were asked to identify strategies and make recommendations for reducing
the frequency of discharges AMA. Patients, physicians, nurses and social workers
identified a need for improved communication. Patients emphasised that providers
should be educated in cultural diversity, interpersonal skills and customer service.
Moreover, patients indicated that there should be more truthful and accurate
communication from providers regarding the wait time.Physicians recommended training programmes that would educate providers on what it
feels like to be ‘on the patients' side’. They also encouraged
thorough communication with patients about their plan of care and the rationale
behind the plan, for example, why certain medications are being prescribed or the
reasons for fasting before a medical test. They suggested that providers avoid making
false promises and provide the patient with documentation regarding the
patient's symptoms and plan of care, as a way to keep the patient
informed.Nurses suggested improving the quality of verbal communication in order to better
manage patients' expectations provide open dialogue regarding the expected
procedures to be performed and minimise making false promises. They also suggested
discussing the hospitalisation process and plan of care when the patient is still in
the emergency department waiting for a room (as one participant described,
“Discharge begins at admission”) and maintain an open line of
communication throughout patient's stay. In addition, nurses would like to see
a cardiologist providing clinical service in the emergency department in order to
address cardiovascular patients' issues earlier on in their hospitalisation
process. Finally, nurses recommended that providers establish a relationship with the
patient's primary care physician because patients trust their own doctor and
might be convinced to stay if the primary physician were in communication with the
patient.
Discussion
Several studies have identified reasons for patient discharges AMA based on primary
data; however, none were conducted in the CVD setting. Until now, little information has
been reported regarding the reasons for a discharge AMA in the CVD setting besides
predictive factors consistently found in analyses of secondary data, such as lower
socioeconomic status, male sex, younger age, Medicaid or no insurance and substance
abuse.19–21 It was unclear to
what extent the factors associated with discharges AMA reported in current literature
would translate to the CVD setting, where decision-making could be considered to be
relatively more deliberate compared with the broader population of patients who leave
AMA, in which mental illness or substance abuse would be more prevalent and could impact
decision-making. In order to explore reasons for discharges AMA that may arise in the
CVD context, we implemented a study focused on patients admitted due to CVD and we
expressly excluded individuals with a comorbid condition of mental illness and/or
substance abuse. We identified four key issues relevant to the discharge AMA in the CVD
setting: (1) patients wanted more involvement in their care; (2) the need to involve the
patient's primary care physician or a specialist (eg, cardiologist); (3)
obligations outside the hospital setting and (4) long wait time.Patients were probed to further understand the need for greater involvement in their
care. During discussions, patients indicated that they gained knowledge about
appropriate care for their CVD condition through repeated exposure to the post-discharge
situation. These patients were aware of the implications of their decision to discharge
AMA and were willing to take responsibility for their decision. The feeling of ownership
was also reflected in their expectations regarding their level of involvement in their
care plan: they sought a greater engagement than was offered. The importance of the
patient's knowledge base and the patient's broader healthcare
institutional context (ie, relationship with specialist provider) in explaining observed
discharges AMA requires further study. The study results suggest that patients admitted
for CVD conditions and who do not present with mental illness or substance abuse
diagnoses may offer different reasons for leaving AMA compared with patient populations
that have been the subject of prior studies. A survey of a larger population of patients
would be needed to validate these findings.These descriptions offered by the participants in the patient FGIs are consistent with a
healthcare model that regards physicians and other healthcare providers as the content
experts, with patients bringing little expertise to the table in terms of managing their
illness. However, in the chronic disease setting, a new model of the physician's
role has been emerging: people with chronic conditions often manage their condition, and
healthcare providers should be consultants supporting them in this role.22 In an American Heart Association (AHA) scientific
statement,23 a panel of physicians reviewed
the literature on factors that appear to significantly influence patient compliance,
such as the patient's knowledge base, historical levels of compliance, the
patient's confidence in their ability to follow physician-recommended behaviours,
the patient's perception of their health status and the benefits of therapy or
behavioural choices, the availability of social support and the complexity of the
regimen. The panel recognised that some of those factors were in turn influenced by the
patient's relationship and communication with the provider. The AHA guide to
primary prevention of CVD24 states, “The
physician must commit the time to make a proper assessment and initiate preventive
efforts. Patients should be involved in developing an effective plan for change and
strategies for altering behavior. A long-term physician-patient relationship is usually
needed for successful prevention and modification of risk factors.” In the AHA
guidelines for primary prevention of CVD and stroke,25 a panel of physicians summarised, “Primary prevention, by its very
nature, requires a lifetime of interactions that virtually define successful
provider-patient relationships.” The examples show that successful
physician–patient relationship is the key in both preventing and treating
CVD.The translation of these guidelines to the inpatient setting would address many of the
gaps in care that were identified during the interviews with patients, physicians and
nurses and social workers, namely (1) failure to determine the patient's
perception of their health status and of the benefits of remaining in the hospital to
complete the stay, (2) failure to involve the patient in developing an effective plan
for change and strategies for altering behaviour post-discharge and (3) failure to
leverage the successful provider–patient relationships that might already exist
between the patient's primary physician or cardiologist. The translation of these
guidelines to the inpatient setting also would address four of the eight most important
characteristics of high quality and safe care, as identified by patients in a
report26 from the Picker Institute (formerly
Picker/Commonwealth Program for Patient-Centred Care): respect for the patient's
values, preferences and expressed needs; coordinated and integrated care; clear
high-quality information and education for the patient and family; continuity, including
through care-site transitions.Evidence from other disease settings supports the utility of leveraging and
strengthening patient–provider relationships for creating optimal discharge
outcomes. A study investigating racial differences in attitudes regarding CVD prevention
and treatment found that the length of relationship between the patient and provider
appeared to influence willingness of the patient to accept physician
recommendations.27 Patients also want
physicians to effectively communicate information to them. A study investigating the
physician–patient relationship as a predictor of quality of life of cardiacpatients after rehabilitation found that physician's promotion of patient
participation has a significant influence on patient's quality of life.28 The quality of patient and provider interactions
is critical to the delivery of patient-centred care, which has been shown to improve
patient's health outcomes and quality of life.29Compared with a previous study,10 there was less
overlap between patients and physicians with regard to the identified reasons for a
discharge AMA. As shown in figure 1, we found
areas of overlap and just as many areas of no overlap across the three groups of
participants in terms of the reasons for discharges AMA. To the extent that there are
gaps between patients and healthcare providers with regard to the perceived reasons for
discharges AMA and/or strategies to address discharges AMA, areas of common ground
should be identified as the building blocks for developing successful interventions
targeting discharges AMA.The current study has a few limitations. Patients without a documented home address were
excluded from the study. With this exclusion, we were unable to recruit homeless
individuals, which form a subpopulation of discharges AMA.30 The response rate was fairly low (30 of 93 or 32.3%) and
therefore the study sample, based on patient focus groups, should not be considered to
be representative of the general population of patients with CVD who discharge AMA. The
strength of the focus group methodology lies in the opportunity to explore care seeking
attitudes and motivations that are nearly impossible to examine using observational data
sets. The patient responses may be subject to non-response bias such that those patients
who participated in the FGIs may differ from those who did not participate in the FGIs
in terms of the stated reasons for a discharge AMA. While results are not generalisable,
the results are novel in that they describe patients' and providers'
perspectives on decision-making around discharges AMA among individuals with a
CVD-related hospitalisation. The information reported in this study can be used in the
design of patient and/or provider surveys, in the design of interventions targeting
discharges AMA or in the development of approaches to improve patient–physician,
patient–nurse or patient–social worker communication in the inpatient
setting.
Conclusions
This study, focused on patients who left AMA after a CVD admission, found that patients
wanted more involvement in their own care, voiced a strong preference for their own
primary care provider/cardiologist, felt that they spent a long time waiting in the
hospital and were motivated to leave the hospital AMA by factors outside the hospital.
While some reasons for discharges AMA, such as preference for their own primary
provider/cardiologist, long wait time and factors outside the hospital were reported by
patients as well as by healthcare providers, other reasons were identified only by the
patients. Programmes developed to address discharges AMA should consider the various
motivations for discharges AMA across the different disease settings in which discharges
AMA occur and, in a first step, build on reasons that have been identified by both
patients and healthcare providers. In addition, healthcare providers should continue
efforts to understand the patient's goals and objectives regarding their hospital
stay, while patients should continue to communicate these goals and objectives to their
provider. To this end, reasons for discharges AMA that have been identified only by
patients or only by providers deserve due attention since both providers and patients
play a critical role in developing and sustaining shared decision-making (and,
consequently, shared responsibility) regarding the hospital (length of) stay and
discharge outcome.
Authors: Eberechukwu Onukwugha; Elijah Saunders; C Daniel Mullins; Françoise G Pradel; Marni Zuckerman; Matthew R Weir Journal: Qual Saf Health Care Date: 2010-06-09
Authors: Thomas A Pearson; Steven N Blair; Stephen R Daniels; Robert H Eckel; Joan M Fair; Stephen P Fortmann; Barry A Franklin; Larry B Goldstein; Philip Greenland; Scott M Grundy; Yuling Hong; Nancy Houston Miller; Ronald M Lauer; Ira S Ockene; Ralph L Sacco; James F Sallis; Sidney C Smith; Neil J Stone; Kathryn A Taubert Journal: Circulation Date: 2002-07-16 Impact factor: 29.690
Authors: Alan P Baptist; Indulekha Warrier; Rachna Arora; Joel Ager; R Michael Massanari Journal: J Allergy Clin Immunol Date: 2007-01-18 Impact factor: 10.793