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Quality of Care and Outcomes of Adults With Asthma Treated by Specialists and Generalists in Managed Care
Albert W. Wu, MD, MPH;
Yuchi Young, DrPH;
Elizabeth A. Skinner, MSW;
Gregory B. Diette, MD, MHS;
Michael Huber, BA;
Alan Peres, BA;
Donald Steinwachs, PhD
Arch Intern Med. 2001;161:2554-2560.
ABSTRACT
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Background The growth of managed health care in the United States has been accompanied
by controls on access to specialty physician services. We examined the relationship
of physician specialty to treatment and outcomes of patients with asthma in
managed care plans.
Methods We conducted a mail survey of adult asthma patients who were enrolled
in 12 managed care organizations and had at least 2 contacts for asthma (International Classification of Diseases, Ninth Revision, Clinical
Modification code 493.x) during the previous 24 months; we also surveyed
their treating physicians. This report concerns 1954 patients and their 1078
corresponding physicians. Treatment indicators included use of corticosteroid
inhalers, use of peak flow meters, allergy evaluation, discussion of triggers,
and patient self-management knowledge. Outcome measures included canceled
activities, hospitalization or emergency department visits, asthma attacks,
workdays lost, asthma symptoms, physical and mental health, overall satisfaction
with asthma care, and satisfaction with communication with physicians and
nurses.
Results Significant differences were noted for patients of specialists and experienced
generalists compared with those of generalist physicians. Peak flow meter
possession was reported by 41.9% of patients of generalists, 51.7% of patients
of experienced generalists, and 53.8% of patients of pulmonologists or allergists.
Compared with patients of generalists, outcomes were significantly better
for patients of allergists with regard to canceled activities, hospitalizations
and emergency department visits for asthma, quality of care ratings, and physical
functioning. Patients of pulmonologists were more likely to rate improvement
in symptoms as very good or excellent.
Conclusions In a managed health care setting, physicians' specialty training and
self-reported expertise in treating asthma were related to better patient-reported
care and outcomes.
INTRODUCTION
WITH MANAGED health care, an established feature in the United States,
worries about quality of care have increased. Because managed care organizations
(MCOs) realize some of their efficiency by controlling access to specialty
care, there is concern that these limitations will affect health outcomes,
particularly for patients with serious or chronic illness. However, few published
studies have shown differences in outcomes of care provided by generalist
vs specialist physicians.
Studies suggest that specialist physicians are more knowledgeable about
conditions that fall within their area of expertise1-3
and are more reliable than generalists at diagnosing them.4-6
Some reports suggest that specialists treating acute illnesses obtain better
patient outcomes,7-8 but for chronic
illness the impact has been more elusive. One report from the Medical Outcomes
Study9 showed similar outcomes for patients
with uncomplicated hypertension or type 2 diabetes mellitus treated by specialists
(cardiologists and endocrinologists, respectively) vs generalists. Another
report found better outcomes when depression was treated by mental health
care providers.5
Asthma provides an excellent example for comparison of generalist and
specialist care. Asthma is a common chronic illness that affects approximately
9 million to 12 million people in the United States and that is associated
annually with approximately 1.8 million emergency department (ED) visits,
500 000 hospitalizations, and 3 million workdays lost.10
Asthma care is provided by generalists and specialists in a variety of treatment
models. Studies of asthma care have shown that intensive treatment and education
are related to better adherence to clinical guidelines and to improved functional
outcomes.11-12 However, the strategies
tested have combined specialty care with intensive education and drug therapy,
making the effects of the different components difficult to separate. A few
studies that have looked specifically at the effect of the physician on treatment
and outcomes suggest that patients treated by specialists13-15
or switching to specialist care16 had fewer
symptoms and ED visits and improved quality of life, albeit at a potentially
higher cost.11 Inpatient studies of generalist
and specialist care have also shown improved outcomes for patients treated
by specialists.17-18 However,
previous studies have not been adjusted for measures of disease severity or
have lacked the patient's perspective. In addition, none have examined differences
in outcomes between allergists and pulmonologists or between generalists with
different levels of asthma management expertise.
In conjunction with a consortium of managed care companies and purchaser
organizations, we conducted a large study of quality of care and outcomes
of patients with asthma enrolled in managed health care.19-20
In this study, we investigated whether there were differences in process of
care and outcomes attributable to the specialty of the health care provider.
PATIENTS AND METHODS
This study was part of a project undertaken by the Managed Health Care
Association Outcomes Management System Consortium. The asthma project involved
several large employers and their managed care partners in a prospective cohort
study to test the feasibility and usefulness of information on process and
patient outcomes to improve the quality of health care.19-20
STUDY POPULATION
Patients were selected from enrollees in each MCO by using claims data
or administrative information to apply the following 3 inclusion criteria:
(1) aged 18 years or older as of September 1, 1993; (2) enrolled in the MCO
at the time of sampling; and (3) at least 2 medical care encounters (ED visits
or hospitalizations) with a diagnosis of asthma (International
Classification of Diseases, Ninth Revision, Clinical Modification code
493.x) in the previous 24 months. This analysis used a subset of patients
from the overall study consisting of 1954 patients who completed the baseline
and 2 follow-up surveys and their 1078 matched physicians who responded to
a separate physician survey (patients were asked to name the physician principally
responsible for managing their asthma care). Compared with patients with matching
physician information, patients without matching physician information (n
= 1533) were similar in sex, asthma symptoms, and number of workdays lost,
but were more likely to be older and white. Since the most salient physician
data were collected on the year 1 survey, the primary analysis examined baseline
data, with outcomes assessed at year 2.
DATA COLLECTION
Information was obtained by means of mailed, self-administered patient
and physician surveys. The patientquestionnaires provided information on demographic
char questionnaires provided information on demographic characteristics, general
health status, asthma-specific health status, use of medical care resources,
disability, and ratings of the quality of care. The physician survey provided
information on specialty training and self-rated asthma expertise.
OUTCOME MEASURES
Nine outcome indicators assessed at year 2 included (1) canceled or
rearranged activities due to asthma during the past 4 weeks (dichotomized
as occurring at all vs not at all); (2) hospitalization or ED visits for asthma
in the past 12 months ( 1 vs none); (3) frequency of asthma attacks (increased
difficulty breathing accompanied by cough, wheezing, chest tightness, or other
symptoms) in the past 4 weeks (3 attacks per week vs fewer); (4) workdays
missed due to health in the past 4 weeks (1 vs none); (5) asthma symptom
scores, based on 7 common asthma symptoms (cough, sputum production, chest
tightness, wheezing, shortness of breath, nocturnal symptoms, and the chronicity
of symptoms between attacks) in the past 4 weeks, with the symptom score calculated
as a summary rating scale ranging from 0 to 5 and higher scores indicating
more severe asthma symptoms; (6) changes in general health status assessed
using the physical component score from the 36-item Short-Form Health Survey
of the Medical Outcomes Study21-22
(higher score indicates better health); (7) changes in general health status
using the mental component score from the same instrument; (8) rating of the
quality of communication with physicians and nurses about asthma (good, fair,
or poor vs excellent or very good); and (9) rating of satisfaction with the
overall quality of care received for asthma during the past 12 months (good,
fair, or poor vs excellent or very good).
PATIENT CHARACTERISTICS
Patient characteristics included age, sex, race, educational level (college
graduate or postgraduate vs others), history of cigarette smoking (yes vs
no), passive exposure to cigarette smoke (yes vs no), presence of chronic
obstructive pulmonary disease (COPD) (yes vs no), and asthma symptom score
(range, 1-5, with a higher score indicating more severe symptoms).
TREATMENT INDICATORS
Treatment indicators were based on National Heart Lung and Blood Institute
National Asthma Education and Prevention Program23
guidelines for patients with asthma and included (1) having a metered dose
inhaler for corticosteroids (ICS) and using it regularly (5 d/wk), intermittently
(1-3 d/wk), or not at all; (2) having a peak flow meter; (3) reporting knowing
everything they should about recognizing triggers, managing flare-ups, or
adjusting medications; (4) having had allergy treatment and/or evaluation;
and (5) having ever discussed asthma triggers with health care providers.
Previous studies have shown improved health outcomes related to use of inhaled
corticosteroids,24-27
and patient education.28-32
PHYSICIAN SPECIALITY
Physician specialty was categorized as generalist, asthma-experienced
generalist, or specialist (pulmonologist or allergist). The variable for the
asthma-experienced generalist was constructed from 2 questions completed by
physicians. The first question was "What is your specialty?" with response
options of internal medicine; family practice; ear, nose, and throat; pulmonology;
allergy; and other. The second question was "Are you an asthma specialist?"
with response options of yes or no. If a physician responded that he or she
is not an asthma specialist and that his or her specialty is internal medicine
or family practice, then that respondent was grouped as generalist, the reference
group in this study. If a physician responded that he or she is an asthma
specialist with a specialty in internal medicine or family practice, then
he or she was grouped as an asthma-experienced generalist. Specialists included
pulmonologists or allergists and were examined together and separately, compared
with generalists.
ANALYSIS
The primary analysis examined the relationship of physician specialty
to treatment indicators (assessed at year 1) and outcomes (reported at year
2). We hypothesized that patients treated by specialists would be more likely
to report adherence to treatment indicators and would have better outcomes
than patients cared for by generalists. We anticipated that in exploratory
analyses, we would find similar levels of performance for pulmonary and allergy
specialists.
The analysis included simple descriptive statistics and multivariable
analyses. Frequency distributions and summary statistics were generated on
the independent variables and dependent variables of interest. Univariate
and bivariate analyses were performed to describe the data, including  2 and t tests, correlations, and the McNemar
test. Mean values were computed for the effect of physician specialty on continuous
outcome indicators.
Multivariable logistic regression analyses were performed on the relationships
between physician specialty and the 9 outcome measures. In our first model,
we controlled for demographics, asthma symptoms, presence of COPD, smoking
and passive smoke exposure, and comorbid conditions that increase asthma symptoms.23 To explore possible mechanisms for specialty-related
differences, in a second model we further adjusted for quality of care indicators
including possession of an ICS and peak flow meter, adequacy of information
about asthma management, discussion of triggers, and allergy testing. A general
linear model was used to analyze the relationships between selected outcomes
and process of health care measures and physician specialty. All statistical
computations were performed using commercially available software (SAS version
6.12; SAS Institute, Inc, Cary, NC).
RESULTS
Overall, the mean age of patients was 47.4 years (range, 18-94 years)
(Table 1). Of the 1954 patients,
69.3% were female, 84.9% were white, and 35.0% had a college degree or postgraduate
education. At baseline, 35.8% reported also having chronic bronchitis or emphysema
(COPD), and 48.9% had smoked cigarettes.The mean asthma symptom score was
2.6. The association between patient baseline characteristics and physician
specialty are presented in Table 1. Patients treated by asthma-experienced generalists or specialists differed
from the patients of generalists in several respects. Compared with patients
of generalists, patients treated by asthma-experienced generalists were more
likely to be white (89.5% vs 80.8%; P<.003). Patients
treated by pulmonologists were more likely to be white (88.7% vs 80.8%; P<.01) and older (mean age, 52.2 vs 47.4 years; P<.01) and to have COPD (44.9% vs 37.8%; P = .03) than patients of generalists. Patients of allergists were
also more likely to be white (91.6% vs 80.8%; P<.001),
but were younger (mean age, 44.7 vs 47.4 years; P<.001),
had more education, and were less likely to have smoked (40.5% vs 50.8%; P<.001). They also had less severe asthma symptoms and
were less likely to report having COPD (25.7% vs 37.8%; P<.001).
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Table 1. Patient Characteristics and Physician Specialty*
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RELATIONSHIP OF PHYSICIAN SPECIALTY TO TREATMENT INDICATORS
Associations between physician specialty and patient-reported variables
of process of care and knowledge about asthma are presented in Table 2. For treatment indicators, overall 80.8% had been told by
medical personnel how to avoid triggers; 76.3% reported knowing how to manage
asthma flare-ups, medications, or triggers; 75.7% had had an allergy evaluation;
72.1% had an ICS; and 48.4% had a peak flow meter at home. Treatment indicators
varied by physician specialty. Patients of asthma-experienced generalists
had several indications of greater consistency of care with National Asthma
Education Program guidelines compared with patients of generalists, including
more knowledge about flare-ups, medication use, and triggers and having an
ICS and peak flow meter. Patients of pulmonologists or allergists had more
knowledge about asthma management and were more likely to have a peak flow
meter. In addition, patients of allergists were more likely to have discussed
triggers and to have had an allergy evaluation, whereas patients of pulmonologists
were more likely to have an ICS.
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Table 2. Treatment Indicators and Physician Specialty*
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PHYSICIAN SPECIALTY AND PATIENT OUTCOMES
In multivariable logistic regression controlling for baseline patient
characteristics, including demographics, asthma symptoms, and comorbid illness
(model 1 in Table 3), there were
significant differences by physician specialty in patient outcomes assessed
1 year later. Compared with patients of generalists, patients of asthma-experienced
generalists were significantly less likely to cancel activities (odds ratio
[OR], 0.55; 95% confidence interval [CI], 0.35-0.88) or miss work (OR, 0.58;
95% CI, 0.35-0.94) in the month before follow-up, or to have been hospitalized
or to have visited an ED for asthma (OR, 0.53; 95% CI, 0.29-0.96). Patients
of pulmonologists rated communication with their physicians and overall quality
of care significantly higher than patients of generalists, but they were also
more likely to be hospitalized or have ED visits (OR, 1.59; 95% CI, 1.08-2.35).
Patients of allergists were significantly less likely than patients of generalists
to cancel activities (OR, 0.57; 95% CI, 0.40-0.82) and to be hospitalized
or have ED visits (OR, 0.63; 95% CI, 0.40-0.97). They rated physician communication
and overall quality of care significantly higher, and showed significant improvements
in asthma symptoms and physical health status.
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Table 3. Multivariate Logistic and Linear Regressions for Physician
Specialty and Patient Outcome Indicators*
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To explore why outcomes might vary by physician specialty, we further
adjusted for quality-of-care indicators, including use of ICS and peak flow
meters, adequacy of information about self-management, discussion of triggers,
and allergy testing. (model 2 in Table 3). We found similar associations to those seen in the previous 2
models, although some relationships were no longer statistically significant.
Patients treated by pulmonologists, on average, had significantly improved
symptom scores and rated overall quality of care as better (OR, 0.54; 95%
CI, 0.33-0.87). Patients of allergists were less likely to cancel activities
(OR, 0.51; 95% CI, 0.34-0.77), or have hospitalization or ED use (OR, 0.55;
95% CI, 0.33-0.90). Patients of allergists also had greater improvement in
asthma symptom scores (P = .07) and physical health
scores (P<.001) and rated overall quality of care
higher (OR, 0.57; 95% CI, 0.36-0.88). Thus, differences in care, as reflected
by the quality indicators, explained some but not all of the benefits associated
with specialist care.
COMMENT
With the growth of managed health care in the United States, concern
has grown regarding measures to control costs. In particular, controls on
access to inpatient care and specialty services have raised questions regarding
the potential for adverse effects on patient health. The results of this study
suggest that asthma care provided by specialists and experienced generalists
was associated with better patient outcomes than was care provided by generalists.
These results were consistent across a range of outcome measures that have
relevance for patients, MCOs, employers, and other purchasers of health care.
In our study, patients treated by specialists were more likely to report
having ICSs, peak flow meters, and adequate knowledge to manage their own
condition. Patients of generalists who had substantial expertise in treating
asthma also had higher rates for all of these process indicators. These patterns
are consistent with treatment guidelines promulgated by the National Asthma
Education Program.23 With regard to outcomes,
patients treated by a specialist or an asthma-experienced generalist had better
outcomes during the ensuing year relative to patients treated by generalists,
even when controlling for a variety of risk factors. The outcomes included
a lower likelihood of canceled activities and workdays lost, fewer asthma
symptoms, and better physical health as measured using the 36-item Short-Form
Health Survey. The difference in workdays lost was equivalent to 0.6 days
per month, or 7.2 days per year. Patients of specialists were most satisfied
with the care they received.
This study is unusual in the opportunity it presented to explore differences
in patient outcomes for 2 different asthma subspecialty groups, pulmonologists
and allergists. As there may be differences in the training, experience, and
approach to asthma care, we compared outcomes of patients treated by pulmonologists
with those treated by allergists, and outcomes of both sets of patients with
those of patients treated by generalists. Our results suggested that there
are modest differences between the specialists that favor allergists. However,
given the differences in patients seen by both specialties, our results should
be considered preliminary and hypothesis generating rather than conclusive.
The performance of experienced generalists in this study is more noteworthy.
Our results support the conclusion that many patients with asthma cared for
by internists and family physicians would benefit from treatment by providers
with more experience in treating asthma. However, it is premature to conclude
that the sickest patients with asthma would do as well if treated by an experienced
generalist as by a pulmonary or allergy specialist. Selection of a physician
specialist is likely to depend on the severity of illness, the difficulty
in managing the condition, patient preferences, and managed health care controls
on access. Even after adjustment for symptom severity, there appears to be
significant unmeasured risk for adverse outcomes. In addition, it is likely
that patients' health status at baseline already reflected the quality of
care being received. As a result, it seems likely that our results underestimate
the differences in outcome attributable to specialty care.
Our study had several limitations. Although a disproportionate burden
of asthma falls on disadvantaged minority urban populations,33-35
the sample in this study was composed of mostly white, well-educated adults
insured through plans affiliated with prominent US companies. Thus, our findings
are most generalizable to adults treated in managed health care settings.
Also, as we oversampled patients who had been hospitalized or had had an ED
visit in the 2 years before the study, asthma symptom scores were more severe
in our study sample than for all adults with asthma. Measures of asthma symptoms
and comorbidity were not sufficiently precise to adjust for all confounding
effects of intrinsic disease severity, which limited our ability to demonstrate
the benefit of treatment consistent with guidelines. In particular, we recognize
the risks of confounding by indication when adjusting for treatments in studies
of asthma. Adjustment for treatments likely accounts for their beneficial
effects and the propensity to use treatments, the latter of which is driven
in part by underlying disease severity or lack of asthma control. Thus, medications
serve as indicators of asthma symptom severity. Without ideal measures of
intrinsic asthma symptoms (in this and any other observational study), we
do not know whether accounting for use of treatments leads to underadjustment
or overadjustment for symptoms. Improvements are needed in predictive modeling
of the natural course of this chronic condition to allow investigators to
assess the contributions of different treatments to patient outcomes over
time.
For the practicing primary care physician, our study raises more questions
than it answers. If there is a volume-outcome relationship for asthma,36 the threshold for a minimum number of patients to
provide ongoing care to achieve or maintain expertise may lie above the 20
or more patients reported by more than two thirds of generalists. At the time
of referral, when is a single consultation, shared care, or assumption of
care the best course of action? The important issue of comanagement was not
addressed in this study. More research is needed to address these questions.
What are the implications for MCO managers? Evidence from this report
and recently updated asthma guidelines37 suggest
that it may be more effective to assign the sickest patients to specialty
care. Determining who is most likely to benefit from specialty care may require
new strategies of patient matching. On the other hand, it is likely that some
of the benefits of subspecialty care reside in structural aspects of the practices
rather than in physicians themselves, such as staff who are knowledgeable
about asthma. There may be other ways to realize the same level of results
when using nonspecialist resources.
This study did not answer a pivotal question of what is different about
the practice of subspecialists and asthma-experienced generalists that contributed
to improved outcomes for their patients. The differential outcomes that we
observed may have arisen from differences in training, experience, services
provided, or unmeasured patient selection effects. We have examined selected
aspects of asthma treatment, and these did not fully explain the differences
in outcomes. To pursue goals of accountability and information that can support
quality improvement, a range of next steps will be important. These steps
include attaining a better understanding of the differences in care provided
by subspecialists, experienced generalists, and generalists with limited asthma
experience. We need a better understanding of the referral and care-seeking
practices that lead patients with asthma of similar severity to be treated
by physicians with different levels of training and experience. Translating
the information learned into new guidelines for training and practice should
contribute toward a system that manages health care to ensure the best outcomes
possible.
AUTHOR INFORMATION
Accepted for publication April 9, 2001.
The study was supported by the Managed Health Care Association Outcomes
Management System Project Consortium, Washington, DC.
We would like to acknowledge the guidance of the following present and
past members of the Managed Health Care Association Outcomes Management System
Consortium Asthma Project Subcommittee: William Glasheen, PhD, Trigon Blue
Cross Blue Shield, Richmond, Va; Joseph M. Healy, Jr, PhD, Harvard Pilgrim
Health Care, Wellesley, Mass; Allan Khoury, MD, PhD, Kaiser-Permanente/Ohio
Region, Cleveland; John Hayes Mason, PhD, Blue Cross Blue Shield of Massachusetts,
Boston; Robert McDonald, MD, Anthem Blue Cross Blue Shield, Indianapolis,
Ind; Richard Neimeyer, Procter & Gamble, Cincinnati, Ohio; and Ann Saladino,
formerly of Alliance Blue Cross Blue Shield, St Louis, Mo. This study was
coordinated by the Health Outcomes Institute, Bloomington, Minn. Employer
members of the Consortium participating in the Asthma Project were Ameritech,
Chicago, Ill; Becton Dickinson and Company, Franklin Lakes, NJ; Commonwealth
of Virginia, Digital Equipment Corporation, Maynard, Mass; GTE Service Corporation,
Irving, Tex; HealthTrust, Inc, Nashville, Tenn; James River Corporation, Richmond;
Marriott International Corporation, Bethesda, Md; Procter & Gamble, Cincinnati;
Promus Companies, Memphis, Tenn; and Xerox Corporation, Stamford, Conn. Managed
care organizations participating in the consortium as partners of the employers
were Aetna Life Insurance Company, Hartford, Conn; Alliance Blue Cross Blue
Shield (Mo), St Louis; Anthem Blue Cross Blue Shield (Ohio), Cleveland; Blue
Cross Blue Shield of Illinois, Chicago; Blue Cross Blue Shield of Massachusetts,
Boston; Blue Cross Blue Shield of Rochester, Rochester, NY; Fallon Community
Health Plan, Worcester, Mass; Harvard Pilgrim Health Care, Wellesley, Mass;
Intermountain Health Care, Salt Lake City, Utah; Kaiser Permanente/Ohio Region,
Cleveland; Matthew Thornton Health Plan, Manchester, NH; The Prudential Health
Care System, Newark, NJ; Trigon Blue Cross Blue Shield (Va), Richmond; United
Health Care, Minnetonka, Minn; and USQA (US Healthcare), Philadelphia, Pa.
Corresponding author and reprints: Albert W. Wu, MD, MPH, Health
Services Research and Development Center, The Johns Hopkins University, 624
N Broadway, Baltimore, MD 21205-1901 (e-mail: awu{at}jhsph.edu).
From the Health Services Research and Development Center, Department
of Health Policy and Management (Drs Wu, Young, and Steinwachs and Ms Skinner),
and the Department of Epidemiology (Drs Wu and Diette), School of Hygiene
and Public Health, and the Department of Medicine, School of Medicine (Drs
Wu, Diette and Steinwachs), The Johns Hopkins University, Baltimore, Md; and
the Managed Health Care Association Outcomes Management System Consortium,
Washington, DC (Mssrs Huber and Peres).
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