Background Systemic Lupus Erythematosus (SLE) may increase this risk of acute pulmonary embolism (PE) and its complications in hospitalised patients. Herein, Nationwide Inpatient Sample (NIS) database from 2003–2011 was analysed to assess the relationship of PE and SLE in hospitalised patients.

Methods NIS database (2003–2011) was queried to identify all adults (age >18 years) with SLE and PE using appropriate ICD-9 codes. Demographic characteristics and in-hospital outcomes were compared between SLE patients with and without a PE. Multivariate logistic regression analysis was used to obtain adjusted odds ratio (OR).

Results Of 2 99 595 hospitalizations of patients with SLE from 2003–2011, 3839 (1.28%) had PE, 1.83 times of the background prevalence with OR 1.85 (p<0.0001). Overall, 89% were females with mean age of 51 years, while those with PE were younger, mean age of 49 years. Rate of PE was higher in African-Americans vs Caucasians (1.5% vs 1.2%) and in males vs females (1.7% vs 1.2%). After adjusting for potential confounders, compared to those without PE, SLE patients with PE had significantly higher inpatient mortality [6% vs 2.0%, OR 2.99 (p<0.001)], greater disability at discharge [31% vs 26%, OR 1.26 (p<0.001)], longer length of stay(LOS) by 2.91 days and higher cost of hospitalisation by $19400 [table 1].

In comparison to 10-year-analysis of National Hospital Discharge Survey (NHDS) database, the results show similar overall increase in risk of developing PE with SLE, mean age, sex ratio, length of stay, higher risk in African-Americans and increased mortality except, in NIS database, PE was more common in males not females (table 2).

Conclusion SLE significantly increases the risk of developing PE in hospitalised patients. Furthermore, PE with SLE is associated with significantly higher mortality and cost of hospitalisation, increased LOS and greater disability at discharge. These results also suggest that African-Americans may have a higher risk of PE but role of sex needs further evaluation. These results suggest thromboembolism prophylaxis should be considered in hospitalised SLE patients but more studies are needed to further elucidate the relationship and risk of PE in SLE, especially in hospitalised patients.