Nutritional Status Score Can Help Predict Prognosis of AAV Patients, Study Says

An instrument that assesses the nutritional status of individuals can be used to predict the prognosis of patients with ANCA-associated vasculitis, a study suggests.

The study, “Controlling Nutritional Status Score is Associated with All-Cause Mortality in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis,” was published in the Yonsei Medical Journal.

Anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis, or AAV, is an autoimmune disease that is caused by the production of autoantibodies — antibodies that wrongly target and attack healthy cells. In AAV, autoantibodies target neutrophils, a type of immune cell. This leads to damage in small blood vessels as well as inflammation and swelling in tissues and organs.

Generally, disease relapse, or refractory illness in the case of granulomatosis with polyangiitis, and end-stage renal disease (ESRD) are considered poor outcomes of AAV, the researchers said.

“While various baseline predictors of outcomes of AAV have been suggested, there is no absolute predictor or method of evaluation at the time of diagnosis to help prognosticate outcomes, which has significant clinical implications,” they added.

Research has found that the controlling nutritional status (CONUT) score, which was originally developed to quickly identify undernutrition in hospitalized patients, was able to predict the prognosis of patients with different types of solid cancers and inflammatory diseases.

In this study, researchers from the Yonsei University College of Medicine, in Korea, set out to investigate if the CONUT score could also be used as a predictor of poor AAV outcomes — all-cause mortality, relapse, or ESRD development.

To explore that possibility, the investigators reviewed the medical records from 196 newly diagnosed AAV patients who had never received immunosuppressive therapy. All patients included in the study were first diagnosed with AAV while they were being followed at the Yonsei University College of Medicine, Severance Hospital, between October 2000 and December 2018.

CONUT scores were calculated based on several parameters normally measured in a regular blood test, including the levels of serum albumin, white blood cell counts, and total cholesterol levels. The blood tests were performed on patients at diagnosis.

From the 196 AAV patients included in the study, 111 had high CONUT scores (equal or greater than 3) at the time of diagnosis, which were indicative of poor nutritional status.Those who had higher CONUT scores at diagnosis also tended to test positive for ANCA autoantibodies and to have higher scores of several AAV measures of disease activity, including the Birmingham Vasculitis Activity Score and the Five Factors Score (FFS).

Further analyses showed that those with CONUT scores higher than 2.5 at diagnosis were at higher risk of ESRD, while those with scores higher than 3.5 were more likely to die prematurely from any cause.

Moreover, statistical analyses confirmed that diabetes, FFS scores, and CONUT scores at diagnosis were all independent predictors of all-cause mortality in this group of AAV patients, whereas serum creatinine (a marker of kidney function) was found to be the only independent predictor of ESRD.

“In conclusion, CONUT score calculated at the time of diagnosis of AAV is associated with all-cause mortality in affected patients,” the researchers said. “Therefore, we suggest that CONUT score may be utilized as a complementary index to predict eventual AAV outcomes in clinical practice.”