Lupus Patients Have Higher Mortality Risk Following Coronary Revascularization

Medha Barbhaiya, MD

Results of a new study involving Medicaid patients is shining new light on the mortality rate of patients with lupus undergoing coronary revascularization procedures.

The 2000-person study, which was presented at the 2019 American College of Rheumatology annual meeting in Atlanta, GA, revealed patients with systemic lupus erythematosus(SLE) were at a 2-fold increased risk of 30-day mortality following coronary revascularization as patients with diabetes mellitus.

With previous research indicating diabetes mellitus and SLE carry similar risks of myocardial infarction, a team of investigators led by Medha Barbhaiya, MD, rheumatologist and clinical researcher at the Hospital for Special Surgery, sought to evaluate whether SLE patients were at an increased risk of mortality after revascularization, as is seen in diabetes mellitus patients. For the current analysis, Barbhaiya and fellow investigators compared outcomes in Medicaid patients with SLE, patients with diabetes mellitus, and in the general population.

Using Medicaid Analytic eXtract(MAX) data, investigators obtained billing claims from the 29 most populated US states from 2007 to 2010. From this data, investigators identified patients between the ages of 18 and 65 with prevalent SLE or diabetes mellitus and greater than 6 months enrollment prior to third code.

For patients in each cohort undergoing first coronary artery bypass grafting(CABG) or percutaneous coronary intervention, investigators calculated post-procedure 30-day mortality rates and mortality rate ratios per 1000 person-years. Investigators noted the use of multivariable logistic regression models, adjusting for age, sex, race, and ethnicity and Charlson index, to calculate odds ratios (OR) and 95% confidence intervals for 30-day mortality post procedures in the SLE compared to the diabetes mellitus and general population cohorts separately.

From analyses of MAX data, investigators identified cohorts of 40,212 SLE patients, 80,424 diabetes mellitus patients, and 160,848 general population patients. In the SLE cohort, 1.51% (608) patients had undergone coronary revascularization procedures compared to 1.47% (1185) in the diabetes mellitus cohort and 0.39% (628) in the general population.

Investigators pointed out mane age at procedure was youngest in SLE patients. Additionally, proportion of black patients was high in SLE.

Analyses revealed patients with SLE had the highest 30-day post-revascularization mortality rate per 1000 person years of observation at 351.35 (95% CI 221.36-557.67). For comparison the unadjusted mortality rate for diabetes mellitus patients was 210.87 (137.49-323.42) and 189.54 (101.98-352.27) in the general population.

In analyses adjusting for confounders included age, sex, race, ethnicity, and Charlson score, patients with SLE had double the risk of 30-day mortality as their counterpart parts with diabetes mellitus(OR 2.13 (95% CI 1.09-4.13)). Investigators also noted a similar, but nonsignificant trend was observed when comparing SLE patients to the general population(OR 1.93 (95% CI 0.85-4.42)).

“In terms of significance of this work, as I mentioned, to our knowledge, this is the first study looking at post-coronary revascularization outcomes and death in lupus patients,” Barbhaiya said.

This study, titled “Mortality Rates After Coronary Revascularization Procedures Among Systemic Lupus Erythematosus Compared to Diabetes Mellitus and General Population Medicaid Patients,” was presented at ACR 2019 by Medha Barbhaiya, MD.