New Index Predicts Mortality Among Nonobese Patients with ANCA-Associated Vasculitis

A new index that uses the triglyceride glucose-body mass index (TyG-BMI) can predict all-cause mortality in nonobese patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, according to a study published online in Frontiers in Medicine.

Calculated using 3 variables — fasting plasma triglyceride level, fasting plasma glucose level, and BMI — TyG-BMI has been used to identify insulin resistance and nonalcoholic fatty liver disease in patients, as well as associated risks including cardiovascular disease and cerebrovascular accidents, explained a research team from the Republic of Korea.

“Given that insulin resistance and its related diseases such as cardiovascular disease and cerebrovascular accidents are generally major risk factors for all-cause mortality in the general population, it could be assumed that TyG-BMI could be a robust predictor of all-cause mortality in ANCA-associated vasculitis patients,” the authors wrote.

The study investigated whether a new index that used TyG-BMI predicted mortality using medical record data for 78 nonobese patients with ANCA- associated vasculitis, 5 of whom had died.

Researchers divided patients into two groups based on TyG-BMI. Patients with TyG-BMI of 187.74 or greater had a significantly higher risk for all-cause mortality; the study reported a relative risk of 9.450.

In addition to TyG-BMI of 187.74 or greater, the study found patient age and Birmingham vasculitis activity score were each associated with all-cause mortality in the cohort. Consequently, researchers created the new index for predicting mortality in nonobese patients with ANCA-associated vasculitis using the following formula: age + 0.2 × Birmingham vasculitis activity score + 2.5 × TyG-BMI ≥ 187.74.

According to the study, patients with a new index score of 27.36 or greater had a significantly elevated risk for all-cause mortality compared with other patients; the relative risk was 284.000.

“Therefore, it is concluded that TyG-BMI and the new index using TyG-BMI at ANCA-associated vasculitis diagnosis could be useful in predicting all-cause mortality,” researchers wrote, “and the predictive ability of the new index … is greater than that of TyG-BMI [alone] in non-obese ANCA-associated vasculitis patients.”

Reference
Park PG, Pyo JY, Ahn SS, et al. New index using triglyceride glucose-body mass index for predicting mortality in patients with antineutrophil cytoplasmic antibody-associated vasculitis. Front Med. 2023;10:1168016. doi:10.3389/fmed.2023.1168016