Modified Body Mass Index at Diagnosis is a Useful Predictor of Mortality in Patients With Antineutrophil Cytoplasmic Antibody-associated Vasculitis.

OBJECTIVE

We investigated whether modified body mass index (mBMI) at diagnosis could predict all-cause mortality during follow-up in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

The medical records of 203 AAV patients with BMI ≥18.5 kg/m were reviewed. mBMI was calculated using an equation mBMI=BMI (kg/m)×serum albumin (g/L). All-cause mortality was considered as a poor outcome, and the follow-up duration based on all-cause mortality was defined as the period from AAV diagnosis to death for deceased patients, and the period from AAV diagnosis to the last visit for surviving patients.

RESULTS

The median age was 59.0 years (35.5% were male). The median BMI and mBMI were 22.8 kg/m and 813.2 kg · g/m · L. Twenty-five patients (12.3%) died. mBMI was well correlated with age, BVAS, FFS, erythrocyte sedimentation rate and C-reactive protein at diagnosis. Deceased patients exhibited significantly lower mBMI at diagnosis compared to surviving patients. AAV patients mBMI ≤570.1 kg · g/m · L showed a significantly higher frequency of all-cause mortality (38.5% vs. 8.5%), and furthermore, exhibited a significantly higher risk for all-cause mortality than those with mBMI >570.1 kg · g/m · L (RR 6.750). mBMI ≤570.1 kg · g/m · L showed a significantly lower cumulative patients' survival rate than those with mBMI >570.1 kg · g/m · L. In the multivariable Cox hazards model analysis, either serum albumin or mBMI was significantly associated with all-cause mortality in AAV patients.

CONCLUSION

In conclusion, mBMI ≤570.1 kg · g/m · L at diagnosis may be a useful predictor of all-cause mortality during follow-up additionally to serum albumin in AAV patients.