Diagnostic value of anti-cyclic citrullinated peptides and association with HLA-DRB1 shared epitope alleles in African rheumatoid arthritis patients

Table 2 Serological and immunogenetic characteristics in RA patients, controls with inflammatory rheumatic diseases, and healthy individuals

Laboratory values	RA	IRD (n = 56)	HI (n = 51)	Sensitivity (n = 50)	Specificity	PPV	NPV	AUC (ROC) (95%) CI
RF IgM (%)	43	3 (6)	4 (8)	77	93	86	88	0.85 (0.79 to 0.91)
RF IgA (%)	47	8 (16)	0 (0)	84	92	85	91	0.88 (0.82 to 0.94)
Anti-CCP2 (%)	46	1 (2)	1 (2)	82	98	96	91	0.90 (0.85 to 0.96)
Anti-CCP3 (%)	43	4 (8)	1 (2)	77	95	90	88	0.86 (0.80 to 0.92)
SE 1 or 2 copies (%)	17	7 (14)	5 (10)	30	88	59	70	0.59 (0.52 to 0.66)
- SE 1 copy (%)	15	7 (14)	5 (10)	27	88	56	68	0.57 (0.51 to 0.64)
- SE 2 copies (%)	2	0 (0)	0 (0)	4	100	100	65	0.52 (0.49 to 0.54)

Anti-CCP, anti-cyclic citrullinated peptides; AUC, area under the curve in the ROC analysis; HI, healthy individuals; IRD, inflammatory rheumatic diseases; RA, rheumatoid arthritis; RF, rheumatoid factor; Sensitivity, the percentage of RA patients who would be identified as having RA by the laboratory tests (positive test results); Specificity, the percentage of control patients (IRD and HI together) who would be identified as not having RA by the laboratory tests (negative test results); PPV, positive predictive value or the proportion of RA patients with positive test results who are correctly diagnosed as having RA; NPV, negative predictive value or the proportion of control patients with negative test results who are correctly diagnosed as not having RA; SE, shared epitope

ISSN: 1478-6362