Background/Purpose :

It is well-established that patients with co-existent Systemic Lupus Erythematosus (SLE) and Anti-Phospho-Lipid-Antibody (aPL) syndrome are at increased risk of cerebrovascular accidents (CVA). Many studies have described that incidence of stroke is significantly higher in SLE and aPL syndrome; However, both these conditions may overlap. Hence, in this nation-wide study, after controlling the potential confounders we studied the individual impact of either condition (SLE and aPL syndrome) on mortality related to CVA. 

Methods :

We queried the Healthcare Cost and Utilization Project’s (HCUP) Nationwide Inpatient Sample (NIS) between 2004 and 2010 and separated the hospitalizations due to or with stroke using ICD 9 diagnostic codes previously established by HCUP. Among this population, we examined the patients with SLE and patients with aPL syndrome and compared their risk of mortality to the all stroke population using the logistic regression model. The model was controlled for confounders which included age, sex, atrial fibrillation, chronic kidney disease, diabetes mellitus, rheumatoid arthritis, chronic rheumatic heart disease and diseases of endocardium. Using SAS 9.2, survey procedures were used to identify multivariate predictors of stroke.

Results :

A total of 1,799,560 (weighted N= 8,874,475) who were hospitalized with stroke were available for analysis out of which 6,890 (weighted N= 33,882) had SLE and 13,769 (weighted N=68,069) had aPL syndrome. On univariate analysis, patients with SLE had 4.43%mortality as compared to 4.35% in patients without SLE (p = 0.47); and patients with aPL syndrome had 11.37% mortality as compared to 4.3% in patients without aPL syndrome (p<0.001). After controlling for confounders mentioned above, com-morbid SLE had no impact on in-hospital mortality (Odds Ratio (OR)=0.93, Confidence Interval (CI)=0.81-1.06, p = 0.2888). Whereas, co-morbid aPL syndrome was associated with significantly increased risk of in-hospital mortality (OR= 2.77, CI=2.59-2.97, p < 0.0001), in patients with stroke.

Table 1: Multivariable predictors of mortality in the study population for stroke (N=1,799,560)

Variables	Model
	OR with 95% CI	P value
Age	1.017 (1.015-1.019)	<0.0001
Female Gender	1.065 (1.046-1.084)	<0.0001
Race(African American vs Caucasian)	1.122 (1.088-1.157)	<0.0001
CCI	1.213 (1.203-1.223)	<0.0001
Systemic Lupus Erythematosus	0.929 (0.810-1.065)	0.2888
Antiphosholipidantibody syndrome	2.772 (2.590-2.968)	<0.0001
Chronic Kidney Disease	2.064 (1.998-2.132)	<0.0001
Atrial fibrillation	1.921 (1.878-1.964)	<0.0001
Diseases of endocardium	0.791 (0.764-0.819)	<0.0001
Rheumatic heart disease	0.762 (0.720-0.806)	<0.0001
Rheumatoid Arthritis	0.718 (0.665-0.776)	<0.0001
Scleroderma	1.284 (0.999-1.650)	0.0508
Diabetes Mellitus	0.580 (0.566-0.594)	<0.0001
Teaching Hospital Status	1.175 (1.116-1.237)	<0.0001

^*CCI = Charlson Co-morbidity Index.

Conclusion :

Though SLE and aPL Syndrome overlap significantly, we found in our analysis that after controlling the significant confounders, SLE alone is not an independent risk factor for increasing mortality risk among the CVA population. Whereas, aPL Syndrome is an independant predictor of increased risk of mortality in patients with CVA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prediction-of-mortality-risk-related-to-cerebrovascular-accidents-in-patients-with-systemic-lupus-erythematosus-sle-vs-anti-phospho-lipid-antibody-apl-syndrome/