Bleeding complications after percutaneous kidney biopsies – nationwide experience from Brunei Darussalam

Table 1 Characteristics of study cohort (continuous variables)

Variables	N = 255	Missing
Mean age in years	35.5 ± 14.3
Mean weight (kg)	72.3 ± 20.1	21
Mean hemoglobin (g/dL)	11.5 ± 2.6	1
Mean platelet (× 109/L)	300 ± 108.3	1
Median creatinine (µmol/L)	158 (80-381)
Median urea (mmol/L)	9.4 (5.5-15.8)
Mean albumin (g/L)	30.1 ± 9.1
Median cholesterol (mmol/L)	5.6 (4.6-8.2)	13
Median urine protein: Creatinine ratio (mg/mmol)	598 (239-1119)	20
Median 24hr urine total protein (g/day)	4.2 (1.7-7.8)	103
Mean complement C3 (g/L)	1 ± 0.4	43
Mean complement C4 (g/L)	0.28 ± 0.14	44
Mean size of biopsied kidney (cm)	11 ± 1.4	40

Table 2 Characteristics of study cohort (categorical variables)

Variables	Classifications	N = 255	Missing
Male gender		120 (47%)
Ethnicity	Malay	207 (81.2%)
	Chinese	6 (2.4%)
	Indian	1 (0.4%)
	Other	41 (16%)
Presence of hypertension		116 (45.5%)
Presence of diabetes		53 (20.8%)
Dialysis before biopsy		26 (10.2%)
Clinical syndrome	Isolated hematuria	4 (1.6%)
	Isolated non-nephrotic proteinuria	25 (9.8%)
	Hemo-proteinuria	26 (10.2%)
	Nephritic syndrome	2 (0.8%)
	RPGN	1 (0.4%)
	Nephrotic syndrome	62 (24.3%)
	Nephritic-nephrotic syndrome	10 (3.9%)
	AKI	28 (11%)
	CKD of undefined cause	92 (36.1%)
	Other	5 (2%)
Presence of urine RBC		108 (43.9%)	9
Presence of ANA		69 (29.5%)	31
Presence of anti-dsDNA		28 (15.5%)	74
Presence of ENA		28 (15.6%)	76
Presence of ANCA		8 (4.2%)	63
Presence of HBV		6 (2.6%)	27
Presence of HCV		2 (0.9%)	34
Presence of HIV		2 (1%)	45
Transplanted (vs. native) kidney		28 (11%)
If native, right (vs. left) kidney		3 (1.3%)
Procedurist	Radiologist 1	82 (34%)	15
	Radiologist 2	28 (11.6%)
	Radiologist 3	68 (28.2%)
	Radiologist 4	13 (5.4%)
	Radiologist 5	49 (20.3%)
	Radiologist 6	1 (0.4%)
CT (vs. USS) guidance		43 (16.9%)
Number of passes	1	1 (0.5%)	57
	2	183 (92.4%)
	3	11 (5.6%)
	4	3 (1.5%)
Number of cores	1	3 (1.5%)	48
	2	188 (90.8%)
	3	12 (5.8%)
	4	4 (1.9%)

RPGN: Rapidly progressive glomerulonephritis; AKI: Acute kidney injury; CKD: Chronic kidney disease; RBC: Red blood cell; ANA: Antinuclear antibody; Anti-dsDNA: Anti-double stranded DNA; ENA: Extractable nuclear antigen antibodies; ANCA: Antineutrophil cytoplasmic antibodies; HBV: Hepatitis B virus; HCV: Hepatitis C virus; HIV: Human Immunodeficiency virus; CT: Computer tomography; USS: Ultrasound scan.

Table 3 Odds ratios for bleeding complications

Variables	Classifications	Univariate logistic regression			Multivariate logistic regression1
		OR	95%CI	P value	OR	95%CI	P value
Age (yr)		1.02	0.99-1.06	0.254
Gender	Female	Reference
	Male	0.49	0.17-1.47	0.204
Ethnicity	Malay	Reference
	Chinese	2.55	0.28-23.2	0.407
	Indian	NA	NA	NA
	Other	NA	NA	NA
Mean weight (kg)		1.01	0.98-1.04	0.428
Hypertension	No	Reference
	Yes	1.2	0.44-3.31	0.720
Diabetes	No	Reference
	Yes	1.8	0.60-5.42	0.297
Dialysis before biopsy	No	Reference
	Yes	2.16	0.57-8.13	0.256
Clinical syndrome	AKI	Reference
	Isolated hematuria	NA	NA	NA
	Isolated non-nephrotic proteinuria	NA	NA	NA
	Hemo-proteinuria	0.33	0.03-3.43	0.355
	Nephritic syndrome	NA	NA	NA
	RPGN	NA	NA	NA
	Nephrotic syndrome	0.28	0.04-1.80	0.180
	Nephritic-nephrotic syndrome	NA	NA	NA
	CKD of undefined cause	1.02	0.26-3.98	0.982
	Other	NA	NA	NA
Mean hemoglobin (g/dL)	> 11	Reference			Reference
	≤ 11	5.04	1.40-18.15	0.0132	4.11	1.12-15.1	0.033
Mean platelet (× 109/L)	> 250	Reference
	≤ 250	3.23	1.13-9.20	0.0282
Median creatinine (µmol/L)	< 265	Reference
	≥ 265	3.62	1.27-10.3	0.0162
Median urea (mmol/L)	< 10	Reference
	≥ 10	3.8	1.19-12.12	0.0242
Mean albumin (g/L)		0.95	0.90-1.01	0.0802
Median cholesterol (mmol/L)		0.91	0.75-1.11	0.346
Presence of urine RBC	No	Reference			Reference
	Yes	6.1	1.7-22	0.0062	5.24	1.43-19.1	0.012
Median urine protein:creatinine ratio (mg/mmol)		1	0.9996-1.0005	0.787
Median 24 h urine total protein (g/day)		0.92	0.78-1.09	0.351
Mean complement C3 (g/L)	≥ 0.8	Reference
	< 0.8	3.35	1.20-9.36	0.0212
Mean complement C4 (g/L)	≥ 0.15	Reference
	< 0.15	3.41	1.10-10.5	0.0332
Presence of ANA	No	Reference
	Yes	2.98	1.03-8.58	0.0442
Presence of anti-dsDNA	No	Reference
	Yes	3.94	1.19-13.1	0.0252
Presence of ENA	No	Reference
	Yes	1.89	0.48-7.48	0.363
Presence of ANCA		NA	NA	NA
Presence of HBV		NA	NA	NA
Presence of HCV		NA	NA	NA
Presence of HIV		NA	NA	NA
Kidney type	Native	Reference
	Transplanted	0.52	0.07-4.10	0.536
Site of kidney		NA	NA	NA
Mean size of biopsied kidney (cm)	> 12	Reference
	≤ 12	2.11	0.58-7.63	0.254
Procedurist	Radiologist 1	Reference
	Radiologist 2	0.30	0.04-2.48	0.265
	Radiologist 3	0.51	0.15-1.73	0.277
	Radiologist 4	0.68	0.08-5.83	0.722
	Radiologist 5	0.17	0.02-1.38	0.101
	Radiologist 6	NA	NA	NA
Guidance	Ultrasound	Reference
	CT	2.39	0.79-7.28	0.124
Number of passes	1	NA	NA	NA
	2	Reference
	3	NA	NA	NA
	4	8.65	0.72-103.7	0.0892
Number of cores	1	35.6	2.97-426.6	0.0052
	2	Reference
	3	NA	NA	NA
	4	5.93	0.57-62.3	0.138

¹Only P value < 0.05 in the multivariate analysis is shown.

²P value < 0.1.

OR: Odds ratio; 95%CI: 95% confidence interval; NA: Not applicable (as zero cell count); AKI: Acute kidney injury; RPGN: Rapidly progressive glomerulonephritis; CKD: Chronic kidney disease; RBC: Red blood cell; ANA: Antinuclear antibody; Anti-dsDNA: Anti-double stranded DNA; ENA: Extractable nuclear antigen antibodies; ANCA: Antineutrophil cytoplasmic antibodies; HBV: Hepatitis B virus; HCV: Hepatitis C virus; HIV: Human Immunodeficiency virus; CT: Computer tomography.

Table 4 Odds ratios for blood transfusion

Variables	Classifications	Univariate logistic regression			Multivariate logistic regression1
		OR	95%CI	P value	OR	95%CI	P value
Age (yr)		1.00	0.95-1.05	0.951
Gender	Female	Reference
	Male	0.44	0.08-2.33	0.338
Ethnicity	Malay	Reference
	Chinese	NA	NA	NA
	Indian	NA	NA	NA
	Other	NA	NA	NA
Mean weight (kg)		0.99	0.95-1.04	0.809
Hypertension	No	Reference
	Yes	0.89	0.19-4.06	0.880
Diabetes	No	Reference
	Yes	0.63	0.07-5.31	0.667
Dialysis before biopsy	No	Reference
	Yes	NA	NA	NA
Clinical syndrome	AKI	Reference
	Isolated hematuria	NA	NA	NA
	Isolated non-nephrotic proteinuria	NA	NA	NA
	Hemo-proteinuria	NA	NA	NA
	Nephritic syndrome	NA	NA	NA
	RPGN	NA	NA	NA
	Nephrotic syndrome	0.45	0.03-7.47	0.577
	Nephritic-nephrotic syndrome	NA	NA	NA
	CKD of undefined cause	1.55	0.17-13.9	0.694
	Other	NA	NA	NA
Mean hemoglobin (g/dL)	> 11	Reference
	≤ 11	6.67	0.79-56.2	0.0812
Mean platelet (10 × 109/L)		0.88	0.79-0.98	0.0212	0.88	0.79-0.98	0.021
Median creatinine (µmol/L)		1.001	0.999-1.003	0.105
Median urea (mmol/L)		1.068	0.999-1.141	0.0522
Mean albumin (g/L)		0.93	0.86-1.01	0.105
Median cholesterol (mmol/L)		0.94	0.71-1.24	0.654
Presence of urine RBC	No	Reference
	Yes	8	0.95-67.5	0.0562
Median urine protein:creatinine ratio (mg/mmol)		1	0.9997-1.0006	0.415
Median 24 h urine total protein (g/day)		0.88	0.66-1.18	0.389
Mean complement C3 (g/L)	≥ 0.8	Reference
	< 0.8	6.32	1.20-33.3	0.0302
Mean complement C4 (g/L)	≥ 0.15	Reference
	< 0.15	5.43	1.16-25.4	0.0322
Presence of ANA	No	Reference
	Yes	6.39	1.21-33.8	0.0292
Presence of anti-dsDNA	No	Reference
	Yes	12.6	2.18-72.5	0.0052
Presence of ENA	No	Reference
	Yes	2.83	0.49-16.2	0.244
Presence of ANCA		NA	NA	NA
Presence of HBV		NA	NA	NA
Presence of HCV		NA	NA	NA
Presence of HIV		NA	NA	NA
Kidney type	Native	Reference
	Transplanted	1.36	0.16-11.7	0.781
Site of kidney		NA	NA	NA
Mean size of biopsied kidney (cm)	> 12	Reference
	≤ 12	1.18	0.22-6.19	0.849
Procedurist	Radiologist 1	Reference
	Radiologist 2	NA	NA	NA
	Radiologist 3	0.79	0.13-4.86	0.797
	Radiologist 4	2.17	0.21-22.6	0.518
	Radiologist 5	0.54	0.05-5.36	0.600
	Radiologist 6	NA	NA	NA
Guidance	Ultrasound	Reference
	CT	0.81	0.10-6.93	0.850
Number of passes	1	NA	NA	NA
	2	Reference
	3	NA	NA	NA
	4	22.4	1.67-300.3	0.0192
Number of cores	1	23	1.71-308.7	0.0182
	2	Reference
	3	NA	NA	NA
	4	15.3	1.30-181.4	0.0302

¹Only p-value < 0.05 in the multivariate analysis is shown.

²p-value < 0.1.

OR: Odds ratio; 95%CI: 95%confidence interval; NA: Not applicable (as zero cell count); AKI: Acute kidney injury; RPGN: Rapidly progressive glomerulonephritis; CKD: Chronic kidney disease; RBC: Red blood cell; ANA: Antinuclear antibody; Anti-dsDNA: Anti-double stranded DNA; ENA: Extractable nuclear antigen antibodies; ANCA: Antineutrophil cytoplasmic antibodies; HBV: Hepatitis B virus; HCV: Hepatitis C virus; HIV: Human Immunodeficiency virus; CT: Computer tomography.