Poor performance of anti-mitochondrial antibodies for the diagnosis of primary biliary cholangitis in female Colombian patients: A single-center study

Table 1 Characteristics of study participants

	Controls	Cases	P value
Age at diagnosis	58.7 ± 11.4	56.9 ± 10.2	0.44
Body mass index	26.8 ± 3.4	23.8 ± 2.4	0.001
Total cholesterol (mg/dL)	221 ± 52.5	221 ± 45.3	0.98
LDL cholesterol (mg/dL)	125 ± 40.2	124.8 ± 41.9	0.99
HDL cholesterol (mg/dL)	54.1 ± 28.7	58.5 ± 10.6	0.48
Triglycerides (mg/dL)	157 ± 64.6	134 ± 54.8	0.16
Fold increment of ALKP above ULN	1.82 ± 1.55	2.84 ± 2.06	0.013
Fold increment of ALT above ULN	2.27 ± 2.94	2.23 ± 1.97	0.94
Fold increment of AST above ULN	2.08 ± 3.37	2.06 ± 1.6	0.97
Fold increment of GGT above ULN	4.43 ± 3.57	6.74 ± 6.78	0.087
Bilirubin (mg/dL)	0.68 ± 0.42	1.5 ± 1.9	0.007
Albumin (g/L)	4.09 ± 0.32	4.05 ± 0.36	0.75
International normalized ratio	0.99 ± 0.09	1.0 ± 0.13	0.56
Ascites, n (%)	2 (4.8)	3 (7)	0.66
Pruritus, n (%)	12 (28.6)	20 (46.5)	0.08
Degree of fibrosis, n (%)1
0	21 (50)	18 (41.9)	0.031
1	14 (33.3)	8 (18.6)
2	1 (2.4)	11 (25.6)
3	4 (9.5)	5 (11.6)
4	2 (4.8)	1 (2.3)
Pattern of anti-nuclear antibodies, n (%)
Peripheral	0 (0)	1 (2.3)	0.37
Homogeneous	0 (0)	0 (0)
Gross speckled	0 (0)	0 (0)
Fine speckled	0 (0)	2 (4.7)
Centromeric	9 (21.4)	12 (27.9)
Nucleolar	2 (4.8)	2 (4.7)
Laminar	0 (0)	0 (0)
Cytoplasmic	6 (14.3)	2 (4.7)
Medications at diagnosis, n (%)
Ursodeoxycholic acid	16 (38.1)	37 (86.0)	< 0.001
Vitamin E	15 (35.7)	3 (7.0)	0.001
Statins	6 (14.3)	2 (4.7)	0.13
Antidiabetics	5 (11.9)	1 (2.3)	0.085
Immunosuppressors	11 (26.2)	13 (30.2)	0.68
Levothyroxine	15 (35.7)	15 (34.9)	0.94
Autoimmune comorbidities, n (%)
Sjögren syndrome	4 (9.5)	9 (20.9)	0.14
Limited systemic sclerosis	2 (4.8)	4 (9.3)	0.41
Diffuse systemic sclerosis	4 (9.5)	2 (4.7)	0.381
Hashimoto´s thyroiditis	5 (11.9)	6 (14)	0.78
Graves´ disease	2 (4.8)	0 (0)	0.15
Systemic lupus erythematosus	1 (2.4)	0 (0)	0.31
Inflammatory bowel disease	0 (0)	0 (0)	-
Rheumatoid arthritis	1 (2.4)	4 (9.3)	0.178
Hemolytic autoimmune anemia	1 (2.4)	0 (0)	0.31
Autoimmune thrombocytopenic purpura	1 (2.4)	0 (0)	0.31

Data are mean ± SD unless stated otherwise.

¹According to the Batts Ludwig classification[33].

ALKP: Alkaline phosphatase; ALT: Alanine amino transferase; AST: Aspartate amino transferase; GGT: Gamma-glutamyl transferase; HDL: High-density lipoprotein; LDL: Low-density lipoprotein; ULN: Upper limit of normal.

Table 2 Sensitivity, specificity and predictive values of each antibody or antibody combination, for the diagnosis of primary biliary cholangitis

Antibody or antibody combination	Sensitivity	Specificity	PPV	NPV
AMA (+)	44.2	76.2	65.5	57.1
ANA (+)	74.4	38.1	55.2	59.3
ASMA (+)	14.0	73.8	35.3	45.6
IgG (+)	26.7	80.0	66.7	42.1
IgM (+)	57.1	85.7	92.3	40.0
AMA (+), ANA (+)	25.6	83.3	61.1	52.2
AMA (+), ANA (-)	18.6	92.9	72.7	52.7
AMA (-), ANA (+)	48.8	54.8	52.5	51.1
AMA (+), ASMA (+)	7.0	100	100	51.2
AMA (+), ASMA (-)	37.2	76.2	61.5	54.2
AMA (-), ASMA (+)	7.0	73.8	21.4	43.7
ANA (+), ASMA (+)	9.3	83.3	36.4	47.3
ANA (+) , ASMA (-)	65.1	54.8	59.6	60.5
ANA (-), ASMA (+)	4.7	90.5	33.3	48.1
AMA (+), IgG (+)	13.3	90.0	66.7	40.9
AMA (+), IgG (-)	46.7	70.0	70.0	46.7
AMA (-), IgG (+)	13.3	90.0	66.7	40.9
AMA (+), IgM (+)	52.4	85.7	91.7	37.5
AMA (+), IgM (-)	4.8	71.4	33.3	20.0
AMA (-), IgM (+)	4.8	100	100	25.9

AMA: Anti-mitochondrial antibodies; ANAs: Anti-nuclear antibodies; ASMA: Anti-smooth muscle antibodies; NPV: Negative predictive value; IgG: Immunoglobulin G; IgM: Immunoglobulin M; PPV: Positive predictive value.