Table 5. Performance of type-sensitive algorithms by race/ethnicity applied to the true cases (N=537) in the Carolina Data Warehouse for Health in 2011.

	diabetes algorithms	N*			Sensitivity (%)			Specificity (%)			PPV (%)
		Total	NHW	Other	Total	NHW	Other	Total	NHW	Other	Total	NHW	Other
Type 1 diabetes	≥1 type 1 codes†	443	288	155	97.0	97.1	96.9	62.1	62.5	61.8	88.7	92.7	81.3
	≥2 type 1 codes	415	276	139	93.6	94.2	92.3	72.7	69.6	75.0	91.3	93.8	86.3
	0 type 2 codes and ≥1 type 1 codes	141	103	38	34.6	37.1	29.2	99.2	98.2	100.0	99.3	99.0	100.0
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.3†‡	413	277	136	96.8	96.7	96.9	84.1	80.4	86.8	94.9	96.0	92.6
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.4	402	273	129	96.3	96.7	95.4	90.9	87.5	93.4	97.0	97.4	96.1
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.5	397	269	128	95.6	96.0	94.6	92.4	91.1	93.4	97.5	98.1	96.1
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.6	383	262	121	93.3	93.8	92.3	96.2	92.9	98.7	98.7	98.5	99.2
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.5 and insulin use OR ratio of type 1 to type 1 and type 2 codes ≥ 0.5 and glucagon use	372	251	121	89.9	89.8	90.0	93.9	92.9	94.7	97.8	98.4	96.7
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.5 and insulin use OR ratio of type 1 to type 1 and type 2 codes ≥ 0.5 and glucagon use OR DAA positive OR C-peptide negative	378	252	126	90.4	90.2	90.8	90.9	92.9	89.5	96.8	98.4	93.7
	Ratio of type 1 to type 1 and type 2 codes ≥ 0.5 OR ≥1 type 1 code and glucagon and no oral medications § OR ≥1 type 1 code and insulin and no oral medications § OR DAA positive OR C-peptide negative	412	276	136	96.5	96.7	96.2	84.1	82.1	85.5	94.9	96.4	91.9
Type 2 diabetes	≥1 type 2 codes	375	219	156	91.9	89.3	93.1	34.4	36.0	31.1	21.1	11.4	34.6
	≥1 type 2 codes and 0 type 1 codes and no insulin use	57	23	34	46.5	35.7	51.7	96.2	95.7	97.3	70.2	43.5	88.2
	Ratio of type 2 to type 1 and type 2 codes ≥ 0.3	151	75	76	91.9	89.3	93.1	84.0	83.5	85.1	52.3	33.3	71.1
	Ratio of type 2 to type 1 and type 2 codes ≥ 0.4	138	65	73	91.9	89.3	93.1	86.9	86.8	87.2	57.2	38.5	74.0
	Ratio of type 2 to type 1 and type 2 codes ≥ 0.5	128	58	70	88.4	82.1	91.4	88.5	88.4	88.5	59.4	39.7	75.7
	Ratio of type 2 to type 1 and type 2 codes ≥ 0.6	116	51	65	84.9	75.0	89.7	90.5	90.1	91.2	62.9	41.2	80.0
	0 type 1 codes and ≥3 type 2 codes and oral medications §	22	5	17	25.6	17.9	29.3	100.0	100.0	100.0	100.0	100.0	100.0
	Ratio of type 2 to type 1 and type 2 codes ≥ 0.4 and oral medications §	78	27	51	70.9	71.4	70.7	96.2	97.7	93.2	78.2	74.1	80.4

Abbreviation: DAA, diabetes auto-antibodies; NHW, non-Hispanic white; PPV, positive predictive value.

True diabetes cases (N=537) and type confirmed by medical record review established our “gold standard” for evaluation of algorithms’ performance.

Only outpatient medications were included for analyses.

^*Number of youth captured;

^†Only 250.xx billing codes were used

^‡The use of ratio was inspired by Klompas et al.’s study ²⁴

^§Include metformin, sulfonylurea, GLP-1 receptor agonists, thiazolidinediones and other hypoglycemic agents, but not insulin and glucagon.