570 The Journal of Rheumatology 2009; 36:3; doi:10.3899/jrheum.080373
Personal non-commercial use only. The Journal of Rheumatology Copyright © 2009. All rights reserved.
Poor Outcomes After Acute Myocardial Infarction in
Systemic Lupus Erythematosus
MANSIA. SHAH,AMBER M. SHAH, and ESWAR KRISHNAN
ABSTRACT. Objective. Systemic lupus erythematosus (SLE) is associated with higher risk for acute myocardial
infarction (MI); but the post-infarction outcomes among these patients are unknown. Our objective
was to compare post-acute MI outcomes in patients with SLE to those with diabetes mellitus (DM)
and those with neither condition.
Methods. We analyzed the risk for prolonged hospitalization and in-hospital mortality following
acute MI in the 1993–2002 US Nationwide Inpatient Sample. We used logistic regression to calcu-
late odds ratios (OR) for prolonged hospitalization and Cox proportional hazards regression to cal-
culate hazard ratios (HR) for in-hospital mortality with and without adjustments for age, sex,
race/ethnicity, socioeconomic status, and presence of congestive heart failure.
Results. For the SLE (n = 2192), DM (n = 236,016), SLE/DM (n = 474), and control (n = 667,956)
groups, the in-hospital mortality rates were 8.3%, 6.2%, 5.7%, and 4.7%, respectively. In multivari-
able regression models, all 3 disease groups had higher adverse outcome risk compared to control.
The OR for prolonged hospitalization was higher for those with SLE (OR 1.48, 95% CI 1.32–1.79)
compared to those with DM (OR 1.30, 95% CI 1.28–1.32). A similar pattern was observed for haz-
ard ratios for in-hospital mortality as well (SLE, HR 1.65, 95% CI 1.33–2.04; DM, HR 1.11, 95%
CI 1.07–1.14).
Conclusion. SLE, like DM, increases risk of poor outcomes after acute MI. These patients need to
be triaged appropriately for aggressive care. (First Release Jan 15 2009; J Rheumatol 2009;
36:570–5; doi:10.3899/ jrheum.080373)
Key Indexing Terms:
SYSTEMIC LUPUS ERYTHEMATOSUS DIABETES MELLITUS
ACUTE MYOCARDIAL INFARCTION LENGTH OF HOSPITAL STAY MORTALITY
From the Department of Internal Medicine, University of Kentucky,
Lexington, Kentucky; and Division of Immunology and Rheumatology,
Department of Medicine, Stanford University, Palo Alto, California, USA.
M.A. Shah, DO; A.M. Shah, MD, MPH, Department of Internal Medicine,
University of Kentucky, Lexington, Kentucky; E. Krishnan, MD, MPH,
Division of Immunology and Rheumatology, Department of Medicine,
Stanford University, Stanford, California.
Address reprint requests to Dr. E. Krishnan, 1000Welch Rd., Suite 203,
Palo Alto, CA, 94304. E-mail: arthritis.md@gmail.com
Accepted for publication September 21, 2008.
In recent years, the short-term mortality rate has improved
substantially in patients with systemic lupus erythematosus
(SLE)
1
.Yet morbidity and mortality from early-onset coro-
nary artery disease remain problems in these patients.
Although investigators have found that the association
between coronary artery disease, atherogenesis, and SLE is
independent of traditional cardiovascular risk factors
2-10
,lit-
tle is known about the risk for adverse outcomes after the
incidenceofacutemyocardialinfarction(MI)amongpeople
with SLE. To our knowledge, only one study has explored
the risk of post-acute MI mortality in patients with SLE.
That study, published in 2004, used the discharge database
of California hospitals and examined the post-acute MI out-
comes in 519 patients with SLE
9
. It did not find a statisti-
cally significant difference between the in-hospital mortali-
ty risk of patients with SLE and that of patients without
SLE
9
.Thatstudydidnotaddresspost-acuteMImorbidityor
compare outcomes of patients with SLE to those with other
diseases.
Some investigators have used diabetes mellitus (DM) as
an analogy for explaining atherogenesis in chronic inflam-
matory autoimmune diseases such as rheumatoid arthritis
(RA)
11
. This is based on the premise that persistent inflam-
matory insult due to RA, like persistent hyperglycemia in
DM,leadstoatherosclerosisandsubsequentacuteMI
10,12-14
.
Whilethisanalogyisappealing,itraisesanotherquestion—
is SLE, like DM, associated with excess post-acute MI mor-
bidity and mortality, and if so, is the quantum of adverse
events comparable to that associated with DM
15,16
? Our
studywasdesignedtoestimateandcomparetheriskofpost-
acute MI morbidity and mortality outcomes in patients with
SLE, patients with DM, patients with both SLE and DM,
and patients with neither disease (controls). Because SLE is
a rare disease and because acute MI and subsequent death
are even rarer events, we chose to use a large, population-
representative hospitalization dataset from the Nationwide
Inpatient Sample (NIS) of the Healthcare Cost and
Utilization Project for our investigation.
MATERIALS AND METHODS
Data source. The NIS is the largest all-payer inpatient care database that is
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