Table 3: Performance of candidate case definitions of end-stage renal disease (ESRD)* using administrative data over 5 years (2004–2008), with data from the Manitoba Renal Program (MRP) registry database as the reference standard

Case definition	Source of data		No. (%) of patients		Measure†	Value (95% CI)
Case definition	Administrative data	MRP data	No. (%) of patients		Measure†	Value (95% CI)
Any 1 claim for outpatient dialysis	No	No	7786	(70.9)	Sensitivity	87.6	(86.3–89.0)
	No	Yes	303	(2.8)	Specificity	91.3	(90.7–91.9)
	Yes	No	739	(6.7)	PPV	74.4	(72.8–76.0)
	Yes	Yes	2149	(19.6)	NPV	96.2	(95.8–96.7)
					Accuracy	90.5	(89.9–91.2)
					κ value	0.74	(0.73–0.76)
Any 2 claims for outpatient dialysis	No	No	7961	72.52	Sensitivity	86.0	(84.7–87.4)
	No	Yes	342	3.12	Specificity	93.4	(92.9–93.9)
	Yes	No	564	5.14	PPV	78.9	(77.4–80.4)
	Yes	Yes	2110	19.22	NPV	95.9	(95.4–96.3)
					Accuracy	91.8	(91.2–92.3)
					κ value	0.77	(0.76–0.78)
Any 2 claims for outpatient dialysis at least 90 d apart	No	No	8495	77.39	Sensitivity	72.0	(70.2–73.8)
	No	Yes	686	6.25	Specificity	99.6	(99.5–99.8)
	Yes	No	30	0.27	PPV	98.3	(97.7–98.9)
	Yes	Yes	1766	16.09	NPV	92.5	(92.0–93.1)
					Accuracy	93.5	(93.0–94.0)
					κ value	0.79	(0.78–0.81)
Any 2 claims for outpatient dialysis at least 90 d apart, with no gap greater than 21 d	No	No	8505	77.48	Sensitivity	47.6	(45.6–49.6)
	No	Yes	1285	11.71	Specificity	99.8	(99.7–99.9)
	Yes	No	20	0.18	PPV	98.3	(97.6–99.0)
	Yes	Yes	1167	10.63	NPV	86.9	(86.2–87.5)
					Accuracy	88.1	(87.5–88.8)
					κ value	0.58	(0.56–0.60)

Note: CI = confidence interval, NPV = negative predictive value, PPV = positive predictive value.  *Definitions are derived from those used in a study by Clement and colleagues.³ †All values are reported as percentages except for kappa values.