Table 2 Performance characteristics of ICD-9-based algorithms for the diagnosis of avascular necrosis (AVN)
Algorithms | Sensitivity %, (95% CI) | Specificity %, (95% CI) | PPV %, (95% CI) | LR+ (95% CI) |
|---|---|---|---|---|
A: ≥1 ICD-9 code for AVN | 81.9 (72.0–89.5) | 99.6 (99.4–99.7) | 66.0 (56.0–75.1) | 190.0 (134.5–268.5) |
B: ≥2 ICD-9 codes for AVN at least 7 days apart | 57.8 (46.5–68.6) | 99.9 (99.8–99.9) | 81.4 (69.1–90.3) | 426.7 (229.9–792.1) |
C: ≥2 ICD-9 codes for AVN at least 30 days apart | 44.6 (33.7–55.9) | 99.9 (99.8–99.9) | 78.7 (64.3–89.3) | 361.8 (186.2–703.1) |
D: ≥3 ICD-9 codes for AVN at least 30 days apart | 44.6 (33.7–55.9) | 99.9 (99.8–100.0) | 82.2 (67.9–92.0) | 452.3 (217.3–941.4) |