ATLANTA --New research found that the 30-day death rate for Medicaid patients with systemic lupus erythematosus (SLE) who underwent coronary revascularization procedures for cardiovascular disease was double that of patients with diabetes mellitus who underwent the same procedures. This study will be presented at the 2019 ACR/ARP Annual Meeting (Abstract # 897).
Systemic lupus erythematosus, referred to as SLE or lupus, is a chronic (long-term) disease that causes systemic inflammation which affects multiple organs and can be deadly. In addition to affecting the skin and joints, it can affect other organs in the body such as the kidneys, brain, the tissue lining the lungs (pleura) and/or heart (pericardium). Many patients experience fatigue, weight loss, and fever.
This research group previously found that although there were similar myocardial infarction risks in patients with SLE or diabetes mellitus (DM), for unknown reasons the rates of coronary revascularization procedures among SLE patients enrolled in Medicaid were 18 percent higher than age- and sex-matched diabetes patients. Although DM patients are known to have an elevated absolute risk of death after coronary revascularization procedures, little is known about mortality after these heart procedures in lupus patients. The researchers conducted a study to determine the outcomes in SLE patients compared to patients with DM as well as patients in the general population. Patients in each cohort were enrolled in Medicaid.
The researchers used Medicaid Analytic eXtract data containing billing claims from the 29 most populated states in the United States from 2007 to 2010. They identified adults 18 to 65 years old with prevalent SLE or DM based on the ninth edition of the International Classification of Diseases (ICD-9) codes. They also included patients without SLE or DM for the general population cohort.
Researchers identified coronary revascularization procedures among 608 SLE patients, 1,185 DM patients and 628 general population patients. Each group had a similar follow-up period of approximately two years (1.7). SLE patients had the highest 30-day post-revascularization mortality rate (351.35) per 1,000 person years of observation compared to 210.4 in the DM group and 189.9 in the general population. The analysis showed that lupus patients had double the odds of death within 30 days after a coronary revascularization compared to patients with DM. They also found a similar, but non-significant trend for SLE patients compared to the general population, although this was limited by very few deaths in the general population group.
"The results suggest that Medicaid SLE patients undergoing coronary revascularization procedures had an increased risk of death compared to similar diabetes mellitus patients having the same procedures. This may be due to severity of cardiovascular disease and overall health status in SLE patients selected for these procedures," said Medha Barbhaiya, MD, a rheumatologist and clinical researcher the Hospital for Special Surgery and the study's lead author. "Future studies accounting for the complexity and indications of the procedures performed, SLE and cardiac disease severity, and investigating causes of post-procedure deaths are required. Given the small number of deaths observed, this study needs to be replicated in a larger cohort."
Although based on a small number of post-procedural deaths, this study found that the SLE patients had 1.7 times higher 30-day mortality rates post-coronary revascularization compared to DM and general population patients, despite being comparatively much younger on average.
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The research was supported by funding from the National Institutes of Health and the
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ABSTRACT
Mortality Rates After Coronary Revascularization Procedures Among Systemic Lupus Erythematosus Compared to Diabetes Mellitus and General Population Medicaid Patients
Background/Purpose: Despite similar myocardial infarction risks in SLE and diabetes mellitus (DM)
patients, individuals with SLE enrolled in Medicaid had substantially higher rates of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) compared to age- and sex-matched DM patients. However, little is known about mortality after coronary revascularization procedures in SLE versus DM and general population patients and we hypothesized that SLE patients would have poorer outcomes. We evaluated 30-day mortality rates following coronary revascularization procedures among SLE compared to DM and general population patients enrolled in Medicaid.
Methods: We utilized Medicaid Analytic eXtract (MAX) data, containing billing claims from 29 most populated U.S. states (2007-2010) and identified adults aged ?18-65 years with prevalent SLE or DM (?3 ICD-9 codes, each ?30 days apart) and >6 months enrollment prior to 3rd code, and patients without SLE or DM ("general population"). Among those in each cohort undergoing first CABG or PCI, we calculated post-procedure 30-day mortality rates (MRs) and mortality rate ratios (MRRs) per 1,000 person-years, with 95% confidence intervals (95% CIs) compared to the DM and general populations separately. We used multivariable logistic regression models, adjusting for age, sex, race/ethnicity and Charlson index, to calculate odds ratios (OR) and 95% CIs, for 30-day mortality post-coronary revascularization procedures in the SLE compared to the DM and general population cohorts separately.
Results: Among 40,212 SLE patients, we identified 608 (1.51%) coronary revascularization procedures; among 80,424 prevalent DM, we identified 1185 (1.47%), and among 160,848 general population patients, there were 628 (0.39%) over similar follow-up periods in each group (approximately 1.7 years). Demographics and deaths within 30 days are shown in Table. Mean age at procedure was youngest in SLE patients and proportion of Black patients was highest in SLE. SLE patients had the highest 30-day post-revascularization mortality rate (351.35 [95% CI 221.36-557.67]) per 1,000 person years of observation, compared to DM (MRR 1.67 [95%CI 1.25-2.21]) and the general population (MRR 1.85 [1.31-2.63]). After multivariable adjustment, the odds of death within 30 days of coronary revascularization procedure were doubled in SLE compared to DM (OR 2.13 [95%CI 1.09-4.13]); a similar but non-significant trend was seen for SLE compared to general population (OR 1.93 [95%CI 0.85-4.42]).
Conclusions: SLE patients had 1.7 times higher 30-day mortality rates post-coronary revascularization compared to DM and general population patients, despite being on average much younger at procedure. After adjusting for demographics and comorbid index, SLE patients were twice as likely to die within 30-days of coronary revascularization procedure as DM patients. Future studies accounting for healthcare utilization, the complexity and indications of the procedures performed, SLE and cardiac disease severity, and investigating causes of post-procedure deaths are required.