Positive Predictive Value of ICD-10 Codes for Cerebral Venous Sinus Thrombosis in Taiwan’s National Health Insurance Claims Database

Figures & data

Figure 1 Process of case ascertainment.

Abbreviations: CGMF, Chang Gung Medical Foundation; ICD-10-CM, International Classification of Diseases, 10th Revision, Clinical Modification.

Table 1 Positive Predictive Value of Individual Case Definition for Identifying Cases of Cerebral Venous Sinus Thrombosis

Case Definitions (ICD-10-CM Codes)	TP, n	FP, n	PPV, % (95% CI)
G08: Intracranial and intraspinal phlebitis and thrombophlebitis
G08 as primary diagnosis	11	1	91.7 (61.5–99.8)
G08 as primary or secondary diagnosis	33	4	89.2 (75.6–97.0)
G08 as primary, secondary, or tertiary diagnosis	43	5	89.6 (77.3–96.5)
G08 in any field of diagnosis	60	8	88.2 (78.1–94.8)
I629: Nontraumatic intracranial hemorrhage, unspecified
I629 as primary diagnosis	1	74	1.3 (0.0–7.2)
I629 as primary or secondary diagnosis	4	125	3.1 (0.9–7.8)
I629 as primary, secondary, or tertiary diagnosis	4	155	2.5 (0.7–6.3)
I629 in any field of diagnosis	4	197	2.0 (0.5–5.0)
I636: Cerebral infarction due to cerebral venous thrombosis, non-pyogenic
I636 as primary diagnosis	11	0	100.0 (71.5–100.0)
I636 as primary or secondary diagnosis	14	0	100.0 (76.8–100.0)
I636 as primary, secondary, or tertiary diagnosis	14	0	100.0 (76.8–100.0)
I636 in any field of diagnosis	15	0	100.0 (78.2–100.0)
I676: Non-pyogenic thrombosis of intracranial venous system
I676 as primary diagnosis	48	3	94.1 (83.8–98.8)
I676 as primary or secondary diagnosis	70	7	90.9 (82.2–96.3)
I676 as primary, secondary, or tertiary diagnosis	84	8	91.3 (83.6–96.2)
I676 in any field of diagnosis	94	9	91.3 (84.1–95.9)

Abbreviations: TP, true positive; FP, false positive; ICD-10-CM, International Classification of Diseases, 10th Revision, Clinical Modification; PPV, positive predictive value; CI, confidence interval.

Table 2 Positive Predictive Value of Combined Case Definitions for Identifying Cases of Cerebral Venous Sinus Thrombosis

Case Definitions (ICD-10-CM Codes)	TP, n	FP, n	PPV, % (95% CI)
G08, I636, I676
G08 or I636 or I676 as primary diagnosis	70	4	94.6 (86.7–98.5)
G08 or I636 or I676 as primary or secondary diagnosis	115	11	91.3 (84.9–95.6)
G08 or I636 or I676 as primary, secondary, or tertiary diagnosis	137	13	91.3 (85.6–95.3)
G08 or I636 or I676 in any field of diagnosis	165	17	90.7 (85.5–94.5)
G08, I636, I676, I629
G08 or I636 or I676 or I629 as primary diagnosis	71	78	47.7 (39.4–56.0)
G08 or I636 or I676 or I629 as primary or secondary diagnosis	117	136	46.3 (40.0–52.6)
G08 or I636 or I676 or I629 as primary, secondary, or tertiary diagnosis	138	168	45.1 (39.4–50.9)
G08 or I636 or I676 or I629 in any field of diagnosis	166	214	43.7 (38.6–48.8)

Note: Seven cases have simultaneous coding with G08, I636, I676, or I629 in any field of diagnosis.

Abbreviations: TP, true positive; FP, false positive; ICD-10-CM, International Classification of Diseases, 10th Revision, Clinical Modification; PPV, positive predictive value; CI, confidence interval.

Table 3 Positive Predictive Value of Individual Case Definition Plus Anticoagulant Use for Identifying Cases of Cerebral Venous Sinus Thrombosis

Case Definitions (ICD-10-CM Codes)	TP, n	FP, n	PPV, % (95% CI)
G08: Intracranial and intraspinal phlebitis and thrombophlebitis
G08 as primary diagnosis	4	0	100.0 (40.0–100.0)
G08 as primary or secondary diagnosis	13	1	92.9 (66.1–99.8)
G08 as primary, secondary, or tertiary diagnosis	18	1	94.7 (74.0–99.9)
G08 in any field of diagnosis	24	1	96.0 (79.7–99.9)
I629: Nontraumatic intracranial hemorrhage, unspecified
I629 as primary diagnosis	1	0	100.0 (2.5–100.0)
I629 as primary or secondary diagnosis	3	0	100.0 (29.2–100.0)
I629 as primary, secondary, or tertiary diagnosis	3	0	100.0 (29.2–100.0)
I629 in any field of diagnosis	3	0	100.0 (29.2–100.0)
I636: Cerebral infarction due to cerebral venous thrombosis, non-pyogenic
I636 as primary diagnosis	10	0	100.0 (69.2–100.0)
I636 as primary or secondary diagnosis	12	0	100.0 (73.5–100.0)
I636 as primary, secondary, or tertiary diagnosis	12	0	100.0 (73.5–100.0)
I636 in any field of diagnosis	13	0	100.0 (75.3–100.0)
I676: Non-pyogenic thrombosis of intracranial venous system
I676 as primary diagnosis	39	0	100.0 (91.0–100.0)
I676 as primary or secondary diagnosis	54	0	100.0 (93.4–100.0)
I676 as primary, secondary, or tertiary diagnosis	60	0	100.0 (94.0–100.0)
I676 in any field of diagnosis	64	0	100.0 (94.4–100.0)

Abbreviations: TP, true positive; FP, false positive; ICD-10-CM, International Classification of Diseases, 10th Revision, Clinical Modification; PPV, positive predictive value; CI, confidence interval.

Table 4 Positive Predictive Value of Combined Case Definitions Plus Anticoagulant Use for Identifying Cases of Cerebral Venous Sinus Thrombosis

Case Definitions (ICD-10-CM Codes)	TP, n	FP, n	PPV, % (95% CI)
G08, I636, I676
G08 or I636 or I676 as primary diagnosis	53	0	100.0 (93.3–100.0)
G08 or I636 or I676 as primary or secondary diagnosis	78	1	98.7 (93.2–100.0)
G08 or I636 or I676 as primary, secondary, or tertiary diagnosis	88	1	98.9 (93.9–100.0)
G08 or I636 or I676 in any field of diagnosis	99	1	99.0 (94.6–100.0)
G08, I636, I676, I629
G08 or I636 or I676 or I629 as primary diagnosis	54	0	100.0 (93.4–100.0)
G08 or I636 or I676 or I629 as primary or secondary diagnosis	79	1	98.8 (93.2–100.0)
G08 or I636 or I676 or I629 as primary, secondary, or tertiary diagnosis	88	1	98.9 (93.9–100.0)
G08 or I636 or I676 or I629 in any field of diagnosis	99	1	99.0 (94.6–100.0)

Abbreviations: TP, true positive; FP, false positive; ICD-10-CM, International Classification of Diseases, 10th Revision, Clinical Modification; PPV, positive predictive value; CI, confidence interval.