Clinical role of albumin to globulin ratio in microscopic polyangiitis: a retrospective monocentric study

We investigated whether albumin to globulin ratio (AGR) at diagnosis may be associated with all-cause mortality in immunosuppressive drug-naïve patients with microscopic polyangiitis (MPA). We retrospectively reviewed the medical records of 88 MPA patients, who were first classified and in whom medications was first initiated in our tertiary Hospital. We collected clinical and laboratory data as well as the rate of all-cause mortality. AGR at diagnosis was calculated as a ratio of serum albumin over globulin fraction (protein–albumin). We compared variables between survived and deceased patients. The multivariable Cox hazard model was conducted to appropriately obtain the hazard ratios (HRs). The mean age at diagnosis was 56.3 years and 24 patients (27.3%) were men. Seven patients died for the mean follow-up period of 49.7 months. Deceased patients were elder than survived patients (P = 0.048). Five factor score (FFS) (2009) (P = 0.001), creatinine (P = 0.026) and AGR (P = 0.007) at diagnosis in deceased patients were higher than those in the survived. In the multivariable Cox hazard model analysis, only AGR at diagnosis (HR 0.004) was inversely associated with all-cause mortality during the follow-up. Furthermore, when the cutoff of AGR for death was set as 0.88, patients with AGR ≤ 0.88 exhibited the lower cumulative patients survival rate than those with AGR > 0.88 (P = 0.006). Among the conventional and MPA-related risk factors for mortality, AGR at diagnosis is inversely associated with all-cause mortality during follow-up in MPA patients.