Do Subspecialists Working Outside of Their Specialty Provide
Less Efficient and Lower-Quality Care to Hospitalized Patients Than Do Primary
Care Physicians?
Arch Intern Med. 2002;162:527-532
Scott R. Weingarten, MD, MPH; Lynne Lloyd, MBA; Chiun-Fang Chiou, PhD;
Glenn D. Braunstein, MD
Background Studies show that subspecialists can provide better quality care
than primary care physicians when working within their subspecialty for
patients with some medical conditions. However, many subspecialists care for
patients outside of their chosen subspecialty. The present study compared the
quality of care provided by subspecialists practicing outside of their
specialty, general internists, and subspecialists practicing within their
specialty.
Methods The severity-adjusted mortality rate and the severity-adjusted
length of stay were used as indexes of quality of care. Data from 5112 hospital
admissions (301 different physicians) for community-acquired pneumonia, acute
myocardial infarction, congestive heart failure, or upper gastrointestinal
hemorrhage at 6 hospitals in the greater Cleveland, Ohio, area were used in
this study. The data were severity adjusted with the CHOICE Severity of Illness
System.
Results Subspecialists working outside of their subspecialty cared for 25%
of hospitalized patients. When comparing patients cared for by subspecialists
practicing outside of their subspecialty, severity-adjusted lengths of stay
were longer for patients with congestive heart failure (23% longer; 95%
confidence interval [CI], 15%-32%), upper gastrointestinal hemorrhage (22%
longer; 95% CI, 7%-39%), and community-acquired pneumonia (14% longer; 95% CI,
5%-24%) than for patients cared for by subspecialists practicing within their
subspecialty. Patients also had a slightly higher hospital mortality rate when
cared for by subspecialists practicing outside of their specialty than by
subspecialists practicing within their subspecialty (mortality rate odds ratio,
1.46; P = .047). In addition,
patients cared for by subspecialists practicing outside of their subspecialty had
longer lengths of stay, and prolongations of stay were observed for patients
with congestive heart failure (16% longer; 95% CI, 8%-26%), upper
gastrointestinal hemorrhage (15% longer; 95% CI, 2%-30%), and
community-acquired pneumonia (18% longer; 95% CI, 9%-28%) than patients cared
for by general internists.
Conclusions Subspecialists commonly care for patients outside of their
subspecialty, despite the fact that their patients may have longer lengths of
stay than those cared for by subspecialists practicing within their specialty
or by general internists. In addition, such patients may have slightly higher
mortality rates than those cared for by subspecialists practicing within their
subspecialty.
Arch Intern Med.
2002;162:527-532
THERE HAS BEEN significant discussion and debate
regarding the role of subspecialists and primary care physicians in providing
care to patients with diverse medical conditions.1-7 Several studies have
reported that subspecialists have more up-to-date medical knowledge and provide
better quality of care than primary care physicians when caring for patients
with conditions within their chosen specialty (eg, cardiologists providing care
to patients with congestive heart failure).1 For example, when
patients with acute myocardial infarction, acute nonhemorrhagic stroke, and
asthma are cared for by subspecialists, they may have better outcomes than when
they are cared for by general internists.1 Moreover, a survey8 of primary care
physicians showed that primary care physicians believed that the scope of
conditions that they treat had increased significantly, and that 24% believed
that the scope of care that they were expected to provide was greater than it
should be.
Recent studies9-11 have suggested that
there may be a surplus of subspecialists, as determined by projecting physician
manpower needs from managed care subspecialty requirements to a population of
patients. A possible surplus of subspecialists may result in some
subspecialists expanding the scope of care that they provide and treating
conditions outside of their chosen specialty.3
Although many studies have compared
subspecialists practicing within their chosen specialty with primary care
physicians, few have examined the quality and efficiency of care provided by
subspecialists practicing outside of their specialty. Using a valid severity of
illness model,12, 13 the present study
compared the quality of care provided by subspecialists caring for patients
outside of their specialty with that provided by general internists and by
subspecialists caring for patients within their specialty.
SUBJECTS AND METHODS
OUTCOME MEASURES
The primary outcome measures used to indicate the quality of care that patients
received were the severity-adjusted mortality rate and hospital length of stay
(LOS). The models were constructed based on patients' demographic and clinical
data.
DATA SOURCE
Six hospitals in the greater Cleveland area, in northeast Ohio, provided information
on their physician subspecialties and patients cared for by these physicians to
this study. All of these hospitals were members of the Cleveland Health Quality
Choice Coalition Consortium.12-14 Among them, 1 is a
rural hospital and 5 are community hospitals. Of the 6 hospitals, only 1 had a
hospitalist program, and none had an internal medicine training program, family
practice training program, or full-time faculty. Two of the hospitals were part
of a health care system and are coded as a single hospital (hospital 4) (Table 1).
The Cleveland Health Quality Choice program was a regional effort of health
care organizations to compare and improve hospital performance.12-14
Lengths of stay and mortality rates for patients
with acute myocardial infarction, congestive heart failure, upper
gastrointestinal hemorrhage, or community-acquired pneumonia were examined in
this study.
Data, including sociodemographic variables,
admission source, medications, medical history, vital signs, selected variables
from the physical examination, results of laboratory tests,
electrocardiographic findings, echocardiographic findings, and do not
resuscitate status, were abstracted from the medical record of each patient by
medical record technicians. There were explicit protocols for data abstraction,
double keystroke entry, identification of out-of-range variables, and
independent verification of data quality at each hospital.
PHYSICIANS AND PHYSICIAN
CLASSIFICATION
The primary physician for selected patients was obtained independently by each
hospital participating in this study. The selected physician was the attending
physician of record in each case. The subspecialty status of physicians was
verified by reviewing information supplied by each hospital (medical staff
office), information provided on the American Medical Association and American
Board of Internal Medicine Web sites, and other available information on
physician subspecialty.15
Physicians were classified as those practicing
within their subspecialty, those practicing outside of their subspecialty,
general internists, or family practitioners. For community-acquired pneumonia,
physicians were classified as practicing within the specialty if they were
trained in infectious diseases or pulmonary medicine. For upper
gastrointestinal hemorrhage, physicians were classified as practicing within
the specialty if they were gastroenterologists. For congestive heart failure or
acute myocardial infarction, physicians were classified as practicing within
the subspecialty if they were cardiologists.
PATIENTS AND PATIENT
CLASSIFICATION
Patients were classified based on the International
Classification of Diseases, Ninth Revision, Clinical Modification,
principal diagnosis code. Only information on patients who were hospitalized in
the 6 hospitals for acute myocardial infarction, congestive heart failure,
upper gastrointestinal hemorrhage, or community-acquired pneumonia between
January 1, 1997, and December 1, 1997, was used in this study. Data of patients
who were younger than 18 years or transferred from other acute-care hospitals
were excluded. Patients may have been hospitalized more than one time, and each
hospitalization was considered separately.
SEVERITY ADJUSTMENT AND THE
CHOICE SEVERITY OF ILLNESS SYSTEM
The CHOICE Severity of Illness System was developed by the Cleveland Health
Quality Choice program.12, 13 The system has
multivariate models that were developed separately for each diagnosis. These
models enable us to predict the mortality (0%-100%) and expected LOS (in days)
for patients with community-acquired pneumonia, congestive heart failure, upper
gastrointestinal hemorrhage, or acute myocardial infarction. These models were
built from the demographic and clinical variables ascertained within the first
48 hours of hospitalization and were validated by the CHOICE Severity of
Illness System in several steps. The initial models were derived from factors
that independently contributed to the risk of death or LOS (P<.01) in logistic or linear regression
models. Length of stay data were log transformed because the data were heavily
skewed. The LOS models excluded patients who died in the hospital or were
transferred to other hospitals.
The performance of the mortality models was
examined by the receiver operating characteristic curve and calibration was
examined by the Hosmer-Lemeshow goodness-of-fit test,16 while the performance
of the LOS models was assessed by the value of R2
and by analysis of residuals. Models used in this study were those reestimated
and examined using the larger data set. The receiver operating characteristic
curve areas and R2
were similar among the diagnoses studied. The receiver operating characteristic
curve areas for mortality and the R2
for LOS for the diagnoses are as follows: acute myocardial infarction, 0.89 and
0.19, respectively; congestive heart failure, 0.85 and 0.14, respectively;
pneumonia, 0.88 and 0.25, respectively; and upper gastrointestinal hemorrhage,
0.91 and 0.23, respectively. Performance of the model was also similar in
different types of hospitals. We used our data to calculate the area under the
receiver operating characteristic curves, and found similar findings.
STATISTICAL ANALYSIS
Differences in patients' demographics and outcomes between physician groups
were analyzed: differences in patients' age, LOS, and risk of death
(severity-adjusted mortality rate) were examined using a Wilcoxon nonparametric
test, while those in sex, race, and mortality were examined using a 
2
test. Multivariate analyses were also performed to analyze differences in
patients' outcomes of physician groups and to adjust patient outcomes for
patient severity of illness. Individual patient severity of illness was first
determined based on each patient's demographics (eg, age) and clinical factors
(eg, coexisting diseases, laboratory results, and vital signs) using the CHOICE
Severity of Illness System, assuming no unmeasured selection effects associated
with mortality rates and LOS due to the limitation of available data.
To estimate the magnitude of the difference in
severity-adjusted LOS between the physician groups, a linear regression analysis
was used. A dummy variable for each physician group was used within the model
to ascertain the differences between each group relative to one another.
Because LOS is log transformed, the antilog of the coefficient in the linear
regression model represents the ratio of severity-adjusted LOS between each
physician group and the reference group. If the coefficient is 0.1, for
example, the ratio of severity-adjusted LOS between a specific physician group
and the reference group is 1.26 (e0.1).
It can also be interpreted that the severity-adjusted LOS of the specific
physician group is 26% higher than the one of the reference group.
To analyze differences in mortality rates,
logistic regression was used with a dummy variable to ascertain the differences
in mortality rates of physician groups. With a certain formula of antilog
transformation, the variable estimate for each dummy variable in the logistic
regression model measures the change in the mortality rate between each
physician group and the reference group.
Confidence intervals were then calculated for
each estimate to reflect the variation within the data and the statistical
significance of the findings. P<.05
was considered statistically significant. SAS statistical software was used for
all of the statistical analyses.17
RESULTS
PATIENT DEMOGRAPHICS AND
CLASSIFICATION
There were a total of 6485 patient hospital admissions that were potentially
eligible for the study. Of these patient hospital admissions, 1373 included
patients who were not clearly identified as being primarily treated by an
internal medicine subspecialist, a general internist, or a family practitioner.
The remaining 5112 patient admissions were enrolled in the study. Among them,
1143 patients (22%) had an acute myocardial infarction, 610 (12%) had an upper
gastrointestinal hemorrhage, 1946 (38%) had congestive heart failure, and 1413
(28%) had community-acquired pneumonia.
When patients were classified according to the
type of physician who provided their care, as seen in Table 2,
a total of 1776 patients (35%) were treated by a physician practicing within
his or her specialty, 1083 (21%) were treated by an internist without an
identified specialty, 990 (19%) were treated by a family practitioner, and 1263
(25%) were treated by a subspecialist practicing outside of his or her
specialty. There were 301 different physicians.
The mean 
SD age of the patients was 72.2 13.9 years, 93% were white, and 51% were men. About 72% of the
patients had Medicare insurance, and 23% had commercial insurance. The mean SD LOS was 5.6
3.9 days.
IN-HOSPITAL MORTALITY
The mean in-hospital mortality was 5.4%. The mean severity-adjusted mortality
was 5.5%. Mortality rates for each hospital are listed in Table 1.
Patients cared for by subspecialists practicing outside of their specialty had
higher mortality rates than those cared for by subspecialists practicing within
their specialty (P = .047)
(analysis 1 in Table 3).
There were no significant differences in the mortality rates when comparing
patients cared for by general internists with those cared for by subspecialists
practicing outside of their specialty (P
= .17) or when comparing patients cared for by general internists with those
cared for by subspecialists practicing within their subspecialty (P = .65) (analysis 2 in Table 3).
Similar results were found for the severity-adjusted mortality rate. Too few
patients with an upper gastrointestinal hemorrhage died to compare mortality
rates by physician types.
LENGTH OF STAY
The mean patient hospital LOS was 5.7 days. The mean LOS was 5.5 days for
general internists' patients, 5.6 days for family practitioners' patients, 5.2
days for patients cared for by subspecialists practicing within their
specialty, and 6.6 days for those cared for by subspecialists practicing
outside of their specialty. The severity-adjusted LOS was longer for patients
treated by subspecialists practicing outside of their specialty than for those
cared for by subspecialists practicing within their specialty (Table 4).
These differences were observed for patients with acute myocardial infarction,
congestive heart failure, gastrointestinal hemorrhage, and pneumonia. In addition,
patients cared for by subspecialists practicing outside of their subspecialty
had longer LOSs than those treated by general internists (Table 4).
COMMENT
This study demonstrated that subspecialists
caring for patients outside of their specialty may provide less efficient care,
as evidenced by longer LOSs, than either subspecialists practicing within their
subspecialty or general internists. In addition, patients cared for by
physicians practicing outside of their specialty may have slightly higher
mortality rates than those cared for by subspecialists practicing within their
specialty. The odds ratio for subspecialists caring for patients outside of
their subspecialty when compared with subspecialists caring for patients within
their subspecialty was 1.46 (P =
.047). Patients cared for by physicians outside of their specialty also had 19%
longer LOSs for the total population of patients, and significantly longer LOSs
for patients with congestive heart failure, upper gastrointestinal hemorrhage,
and community-acquired pneumonia. These differences suggest that subspecialists
practicing outside of their specialty may provide less efficient care and
possibly lower-quality care when compared with physicians providing care within
their subspecialty.
When comparing the mortality rates of patients
treated by physicians practicing outside of their specialty with those of
patients cared for by general internists, there were no statistically
significant differences. However, LOSs for patients cared for by subspecialists
practicing outside of their specialty were 17% longer than those of patients
cared for by general internists, and prolongations of stay were observed for
patients with congestive heart failure, upper gastrointestinal hemorrhage, and
community-acquired pneumonia. Therefore, LOSs were shorter when patients were
treated by general internists rather than subspecialists practicing outside of
their specialty.
This study is one of few that have examined the
potential implications of having subspecialists care for patients outside of
their subspecialty. The strengths of the present study include the following:
(1) it had more than 5112 patients treated at 6 different hospitals and (2) a
severity-of-illness adjustment was performed to minimize the chance that
differences in LOSs and mortality rates could be attributed to differences in
patient severity of illness.12, 13
This study also has limitations. First, teams of
physicians often care for hospitalized patients, including different
subspecialists. It can be difficult to attribute the efficiency or quality of
care to a single physician or type of physician. However, the identified
physician in the study was the primary attending physician of record as coded
by the hospital. Although we attempted to control for the number of patients
with a particular condition treated by a physician, we only had access to the
information of patients treated in the hospitals that participated in this
study. It is possible that a physician might have admitted patients to
hospitals other than these 6. Therefore, the real volume of patients treated by
physicians in this study might be higher than what was measured. Information
regarding the volume of patients treated by different types of physicians could
be inaccurate and, thus, was not used as a variable in the analyses. In
addition, there were some differences in demographics between those patients
cared for by general internists, subspecialists practicing within their
subspecialty, and subspecialists practicing outside of their subspecialty.
However, patients' LOSs and mortality rates were adjusted for patient severity
of illness, which should account for any difference that patient severity of
illness or age might have had on LOS. In addition, the LOS may impact hospital
mortality rates. Finally, this study used the patient as the unit of analysis
rather than the hospital or the physician.
The observed differences in LOS may demonstrate
that physicians caring for patients outside of their chosen specialty are less
familiar with patients with these conditions because volume-outcome
relationships have been shown for many conditions in medicine, and
subspecialists practicing outside of their subspecialty may be a marker for low
patient volume. Moreover, subspecialists frequently care for patients outside
of their chosen subspecialty, because 25% of patients were cared for by
subspecialists practicing outside of their subspecialty. A recent study8 showed that many
primary care physicians believe that the scope of conditions that they are
expected to treat is greater than it ought to be. Because many subspecialists
may perform primary care and treat hospitalized patients outside of their
subspecialty, it is possible that subspecialists may have similar concerns that
the scope of conditions that they treat outside of their subspecialty is
greater than it should be.
In conclusion, subspecialists commonly care for
patients outside of their subspecialty. Patients cared for by subspecialists
practicing outside of their subspecialty had longer LOSs and possibly higher
mortality rates than those cared for by subspecialists practicing within their
subspecialty; they also had longer LOSs when compared with those cared for by
general internists. If patients are cared for by subspecialists practicing
outside of their specialty, their LOSs, and possibly even mortality rates, may
be higher than those of patients cared for by subspecialists practicing within
their subspecialty.
Author/Article Information
From the Department of Health Services Research (Zynx Health, Inc),
Cedars-Sinai Health System, Beverly Hills, Calif (Drs Weingarten and Chiou);
and the Department of Medicine, University of California, Los Angeles, UCLA
School of Medicine (Drs Weingarten and Braunstein). Ms Lloyd is an independent
consultant.
Corresponding author and reprints: Scott R. Weingarten, MD, MPH, Zynx Health,
Inc, Cedars-Sinai Health System, 9100 Wilshire Blvd, Suite 655E, Beverly Hills,
CA 90212 (e-mail: [log in to unmask]).
Accepted for publication July 16, 2001.
We thank Dwain Harper, DO, for his assistance
with this study.
REFERENCES
1.
Harrold LR, Field TS, Gurwitz JH.
Knowledge, patterns of care, and outcomes of care for general internists and
specialists.
J Gen Intern Med.
1999;14:499-511.
MEDLINE
2.
Meyer GS, Jacoby I, Krakauer H, et al.
Gastroenterology workforce modeling.
JAMA.
1996;276:689-694.
MEDLINE
3.
Rhee SO, Luke RD, Lyons TF, Payne BC.
Domain of practice and the quality of physician performance.
Med Care.
1981;19:14-23.
MEDLINE
4.
Greenfield S, Nelson EC, Zubkoff M, et al.
Variations in resource utilization among medical specialties and systems of
care: results from the Medical Outcomes Study.
JAMA.
1992;267:1624-1630.
MEDLINE
5.
Kassirer JP.
Access to specialty care.
N Engl J Med.
1994;331:1151-1153.
MEDLINE
6.
Ayanian JZ, Guadagnoli E, McNeil BJ, Cleary CD.
Treatment and outcomes of acute myocardial infarction among patients of
cardiologists and generalist physicians.
Arch Intern Med.
1997;157:2570-2576.
MEDLINE
7.
Jollis JG, DeLong ER, Peterson ED, et al.
Outcome of acute myocardial infarction according to the specialty of the
admitting physician.
N Engl J Med.
1996;335:1880-1887.
MEDLINE
8.
St Peter RF, Reed MC, Kemper P, Blumenthal D.
Changes in the scope of care provided by primary care physicians.
N Engl J Med.
1999;341:1980-1985.
MEDLINE
9.
Weiner JP.
Forecasting the effects of health reform on US physician workforce requirement:
evidence from HMO staffing patterns.
JAMA.
1994;272:222-230.
MEDLINE
10.
Cooper RA.
Seeking a balanced physician workforce for the 21st century.
JAMA.
1994;272:680-687.
MEDLINE
11.
Demaria AN, Lee TH, Leon DF, et al.
Effect of managed care on cardiovascular specialists: involvement, attitudes
and practice adaptations.
J Am Coll Cardiol.
1996;28:1884-1895.
MEDLINE
12.
Rosenthal GE, Harper DL.
Cleveland Health Quality Choice: a model for collaborative community-based
outcomes assessment.
Jt Comm J Qual Improv.
1994;20:425-443.
MEDLINE
13.
Rosenthal GE, Harper DL, Quinn LM, Cooper GS.
Severity-adjusted mortality and LOS in teaching and nonteaching hospitals:
results of a regional study.
JAMA.
1997;278:485-490.
MEDLINE
14.
Rosenthal GE, Quinn LM, Harper DL.
Declines in hospital mortality associated with a regional initiative to measure
hospital performance.
Am J Med Qual.
1997;12:103-112.
MEDLINE
15.
Reed Elsevier Inc and the American Board of Medical Specialists.
The Official ABMS Directory of Board
Certified Medical Specialists.
30th ed. New Providence, NJ: Marquis Who's Who
A
Division of Reed Elsevier Inc; 1977.
16.
Hanley JA, McNeil BJ.
The meaning and use of the area under a receiver operating characteristic (ROC)
curve.
Radiology.
1982;143:29-36.
MEDLINE
17.
SAS Software: SAS/Base and SAS/Stat, Version
6.12.
Cary, NC: SAS Institute Inc; 1996.
Edward E.
Rylander, M.D.
Diplomat American
Board of Family Practice.
Diplomat American
Board of Palliative Medicine.