Predicting Mortality in Microscopic Polyangiitis with Renal Involvement: A Survival Analysis Based on 64 Patients

Figures & data

Table 1.  Clinical background of all patients (mean ± SD).

Characteristic	Value
Year	59.87 ± 1.98
Gender (male/female)	40/24
Systolic blood pressure (mmHg)	135.66 ± 12.17
Diastolic blood pressure (mmHg)	88.90 ± 9.04
ESR (mm/h)	99.12 ± 7.84
hsCRP (mg/dL)	28.98 ± 5.22
24 h proteinuria (g/24 h)	2.31 ± 0.33
White blood cell count (×10^9/L)	9.86 ± 1.16
Neutrophil count (×10^9/L)	8.37 ± 2.59
Lymphocyte count (×10^9/L)	1.49 ± 0.68
Hb (g/L)	84.06 ± 5.21
Platelet count (×10^12/L)	218.31 ± 13.02
Albuminemia (g/dL)	30.04 ± 0.68
Serum creatinine level (μmol/L)	459.73 ± 53.38
Total cholesterol (mmol/L)	5.87 ± 1.24
Triglyceride (mmol/L)	2.68 ± 0.61
MPO-ANCA	7.48 ± 1.05
PR3-ANCA	0.74 ± 0.28
BVAS	22.20 ± 0.36
Number of patients with renal biopsy (%)	64 (100%)
Mesangial proliferative glomerulonephritis and focal segmental glomerulosclerosis	8 (12.5%)
Focal segmental crescent formation	24 (37.5%)
Crescentic glomerulonephritis	32 (50%)

Notes: ANCA, anti-neutrophil cytoplasmic antibody; BVAS, Birmingham vasculitis activity score; ESR, erythrocyte sedimentation rate; Hb, hemoglobin; MPO, myeloperoxidase; PR3, proteinase-3; hsCRP, high-sensitivity C-reactive protein.

Table 2.  Comparison of patients reaching the primary end point.^a

	Group A (n = 30)	Group B (n = 34)	p-Value
Year	60.38 ± 14.33	58.88 ± 17.02	NS
Systolic blood pressure (mmHg)	130.79 ± 13.48	139.02 ± 13.01	NS
Diastolic blood pressure (mmHg)	86.25 ± 9.76	90.23 ± 8.99	NS
ESR (mm/h)	76.38 ± 48.45	112.06 ± 24.04	<0.01
hsCRP (mg/dL)	26.57 ± 7.92	37.28 ± 5.29	NS
24 h proteinuria (g/24 h)	3.23 ± 0.67	2.49 ± 1.17	NS
White blood cell count (×10^9/L)	11.18 ± 5.97	9.28 ± 5.25	NS
Neutrophil count (×10^9/L)	9.46 ± 7.88	7.28 ± 5.29	NS
Lymphocyte count (×10^9/L)	1.7 ± 0.79	1.4 ± 0.56	NS
Hb (g/L)	98.92 ± 6.49	78.82 ± 2.25	<0.01
Platelet count (×10^12/L)	257.6 ± 58.29	207.5 ± 87.17	NS
Albuminemia (g/dL)	31.57 ± 4.21	29.43 ± 3.08	0.01
Serum creatinine level (μmol/L)	244.7 ± 126.71	623.9 ± 245.51	0.01
Total cholesterol (mmol/L)	5.78 ± 1.36	5.90 ± 1.19	NS
Triglyceride (mmol/L)	2.49 ± 0.70	2.78 ± 0.58	NS
MPO-ANCA	8.03 ± 2.90	8.76 ± 5.78	NS
PR3-ANCA	0.77 ± 0.28	0.68 ± 0.21	NS
BVAS	20.18 ± 1.55	22.40 ± 1.32	NS

Notes: ANCA, anti-neutrophil cytoplasmic antibody; BVAS, Birmingham vasculitis activity score; ESR, erythrocyte sedimentation rate; Hb, hemoglobin; MPO, myeloperoxidase; NS, no significance; PR3, proteinase-3; hsCRP, high-sensitivity C-reactive protein.

^aGroup A did not reach the primary end point; group B reached the primary end point.

Table 3.  Logistic regression analysis of outcome.

	OR value	p-Value	5%–95% CI
Scr (μmol/L)	1.01	<0.01	1.007–1.024
ESR (mm/h)	1.03	<0.01	1.009–1.042
sALB (g/dL)	0.85	<0.05	0.726–0.986
Hb (g/L)	0.96	<0.01	0.934–0.989

Notes: CI, confidence interval; ESR, erythrocyte sedimentation rate; Hb, hemoglobin; Scr, serum creatinine; sALB, serum albumin; OR, odds ratio.

Table 4.  Multivariate analysis of factors associated with survival in 64 patients using a Cox proportional hazards regression model.

	p-Value	β	5%–95% CI
ESR	0.045	1.02	1.00	1.04
Scr	<0.001	1.00	1.00	1.01

Notes: CI, confidence interval; ESR, erythrocyte sedimentation rate; Scr, serum creatinine.

Figure 1.  Survival and serum creatinine in the entire group. Scr > 459.73 umol/L at presentation was associated with a significantly poor prognosis.

Figure 2.  Survival and ESR in the entire group. ESR > 99.12 mm/h at presentation was associated with a significantly poor prognosis.

Figure 3.  Survival and serum albumin in the entire group. sALB < 30.04 g/dL at presentation was associated with a significantly poor prognosis.

Figure 4.  Survival and hemoglobin in the entire group. Hb < 84.06 g/dL at presentation was associated with a significantly poor prognosis.

Figure 5.  Diagnostic performance of serum creatinine for the identification of survival. Area under the curve (AUC) was 0.94 using a cutoff of 395.05 μmol/L; sensitivity was 94.1% and specificity was 92.3%.

Figure 6.  Diagnostic performance ESR for the identification of survival. Area under the curve (AUC) was 0.8 using a cutoff 73 mm/h; sensitivity was 94% and specificity was 70%. Diagonal segments are produced by ties.