Table 2.

Predictive value for the progression from UA to RA within one year using different cut-off values for erosions in hands and/or feet

Number of erosive joints	n	PPV	(95% CI)	NPV	(95% CI)	Specificity	(95% CI)	Sensitivity	(95% CI)	LR+	LR-	AUC (SEM)
≥1	148	45	37-53	75	70-79	77	73-82	42	34-50	1.8	0.75	0.60 (0.028)
≥2	83	53	42-64	73	69-78	89	86-92	28	21-34	2.5	0.81	0.58 (0.028)
≥3	50	54	40-68	72	68-76	94	91-96	17	11-23	2.6	0.89	0.55 (0.028)
≥4	24	54	34-74	70	66-74	97	95-99	8	4-12	2.6	0.95	0.53 (0.028)
≥5	15	73	51-96	70	66-74	99	98-100	7	3-11	6.2	0.94	0.53 (0.028)

n = number of UA patients positive for this cut off.

AUC = area under the curve; CI = confidence interval; LR+ = positive likelihood ratio; LR- = negative likelihood ratio; NPV = negative predictive value; PPV = positive predictive value; RA = rheumatoid arthritis; SEM = standard error of measurement; UA = undifferentiated arthritis.