**3. Results**

#### *3.1. Di*ff*erences between Patients with Preserved Renal Function and Renal Failure*

All patients enrolled in this study were ethnically homogenous. The etiology of the 44 patients was as follows: ANCA-associated vasculitis (*n* = 34), ANCA-negative vasculitis (*n* = 6), and anti-GBM disease (*n* = 4). We first divided the patients into two groups according to their renal outcomes at 1 year post diagnosis. The characteristics of the 37 cases with preserved renal function (pre-dialysis group) and 7 cases with renal failure (maintenance HD group) are shown in Table 1 and Figure 2. WBC, Neu, Plt, Cr, eGFR and the anti-GBM antibody all showed significant di fferences between the groups. We also observed significant di fferences in NLR (8.2 (2.0–32.0) vs. 3.9 (2.8–8.4), *p* = 0.019) and PLR (265.7 (82.9–2255.0) vs. 126.0 (107.1–269.0), *p* = 0.008) between the pre-dialysis and maintenance HD groups, respectively. Multivariate regression analysis revealed that renal function was the strongest influencing factor for renal outcome (stdβ = 0.363, *p* = 0.012). There was also a trend suggesting the significance of NLR as a predictive value (stdβ = 0.276, *p* = 0.052); PLR, however, did not display this significance (stdβ = 0.207, *p* = 0.148).


**Table 1.** Patient's characteristics between the pre-dialysis and maintenance hemodialysis (HD) groups.

Data are presented as the mean ± standard deviation, median (range), or number (%). HD—hemodialysis; RPGN—rapidly progressing glomerulonephritis; CGN—crescentic glomerulonephritis; eGFR—estimated glomerular filtration rate; CRP—C-reactive protein; ESR—erythrocyte sedimentation rate; MPO—myeloperoxidase; ANCA—anti-neutrophil cytoplasmic antibody; PR3—proteinase 3; GBM—glomerular basement membrane; NLR—neutrophil-to-lymphocyte ratio; PLR—platelet-to-lymphocyte ratio.

**Figure 2.** Neutrophil-to-lymphocyte ratios (NLR) and platelet-to-lymphocyte ratios (PLR) in the pre-dialysis and maintenance hemodialysis (HD) groups. (**a**) NLR in the pre-dialysis and maintenance HD groups. (**b**) PLR in the pre-dialysis and maintenance HD groups. The top and the bottom of the boxes are the first and third quartile, respectively. The length of the box represents the interquartile range. The line through the middle of each box represents the median. The error bars show the minimum and maximum values (range). \*, *p* < 0.05; \*\* *p* < 0.01. NLR—neutrophil-to-lymphocyte ratio; PLR—platelet-to-lymphocyte ratio; HD—hemodialysis.

The ROC curves analyses were performed to define the cutoff value of PLR and NLR for predicting renal outcomes after 1 year (Figure 3). Both NLR and PLR were accurate predictors of renal outcomes, with an area under the curve (AUC) of 0.782 in NLR and 0.819 in PLR. The cutoff values defined were 4.0 in NLR, with a sensitivity of 78.4% and specificity of 71.4%, and 137.7 in PLR, with a sensitivity of 89.2% and specificity of 71.4%.

**Figure 3.** The receiver operating characteristic (ROC) curve of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) for predicting renal outcome. (**a**) The ROC curve of NLR showing an area under the curve (AUC) of 0.782. An NLR of 4.0 was the cutoff value with a sensitivity of 78.4% and a specificity of 71.4%. (**b**) The ROC curve of PLR showing an AUC of 0.819. The cutoff value of 137.7 was determined with a sensitivity of 89.2% and a specificity of 71.4%.

#### *3.2. Di*ff*erences between Patients with Temporary Hemodialysis and Maintenance Hemodialysis*

Since renal function on admission was a strong predicting factor for renal outcome, we divided the 13 patients who required HD into two groups as follows: 6 patients with recovery of renal function (temporary HD group) and 7 patients with persistent renal failure (maintenance HD group). Sex, WBC and Neu showed significant differences between the groups (Table 2). NLR was significantly higher in the temporary HD group compared to the maintenance HD group (12.4 (4.1–21.4) vs. 3.9 (2.8–8.4), *p* = 0.008, respectively, Figure 4). However, no significant difference was observed in PLR between the temporary HD group and the maintenance HD group (341.7 ± 217.7 vs. 156.1 ± 62.6, *p* = 0.053, respectively). The ROC curve analysis showed that an NLR of 5.0 could predict withdrawal from HD with a sensitivity of 83.3% and a specificity of 85.7%, with an AUC of 0.929 (Figure 5).


**Table 2.** Patient's characteristics between temporary the HD and maintenance HD groups.

Data are presented as the mean ± standard deviation, median (range), or number (%). HD—hemodialysis; RPGN—rapidly progressing glomerulonephritis; CGN—crescentic glomerulonephritis; eGFR—estimated glomerular filtration rate; CRP—C-reactive protein; ESR—erythrocyte sedimentation rate; MPO—myeloperoxidase; ANCA—anti-neutrophil cytoplasmic antibody; PR3—proteinase 3; GBM—glomerular basement membrane; NLR—neutrophil-to-lymphocyte ratio; PLR—platelet-to-lymphocyte ratio.

**Figure 4.** Neutrophil-to-lymphocyte ratios (NLR) of the temporary and maintenance hemodialysis (HD) groups. The top and the bottom of the boxes are the first and third quartile, respectively. The length of the box represents the interquartile range. The line through the middle of each box represents the median. The error bars show the minimum and maximum values (range). \*\* *p* < 0.01. NLR—neutrophil-to-lymphocyte ratio; HD—hemodialysis.

**Figure 5.** The receiver operating characteristic (ROC) curve for neutrophil-to-lymphocyte ratio (NLR) for recovery from renal failure. The NLR of 5.0 was determined to be a cutoff value with a sensitivity of 83.3% and a specificity of 85.7%, and the area under the curve was 0.929.

We further investigated histological changes in the temporary HD group and maintenance HD group (Table 3, Figures 6 and 7). The number of globally sclerotic glomeruli was significantly lower in the temporary HD group (9.0% ± 10.1% vs. 53.0% ± 9.7%, *p* < 0.001), whereas the number of glomeruli with cellular crescent was significantly higher in the temporary HD group (27.9 (0–73.3) vs. 0 (0–13.3), *p* = 0.022).

**Table 3.** Histological changes in the temporary hemodialysis (HD) and maintenance HD groups.


Data are presented as the mean ± standard deviation. HD—hemodialysis.

**Figure 6.** Quantification of histological findings in the temporary and maintenance hemodialysis (HD) groups. (**a**) Comparison of the percentage of glomeruli with cellular crescent between the temporary and maintenance HD groups. (**b**) Comparison of the percentage of globally sclerotic glomeruli between the temporary and maintenance HD groups. Bars indicate mean ± SEM. \*, *p* < 0.05; \*\*\* *p* < 0.001. HD—hemodialysis.

**Figure 7.** Histological findings in each group. Representative images of Periodic acid-Schiff staining on paraffin-embedded kidney sections, from patients in (**a**) the temporary hemodialysis (HD) group, and (**b**) the maintenance HD group. Cellular crescentic glomeruli were dominant in the temporary HD group, whereas most of the glomeruli were globally sclerotic in the maintenance HD group.
