Table. Positive predictive value and sensitivity of ICD-9-CM diagnosis code–based case definitions for NTM infection in 2006–2014 Medicare data by using Bronchiectasis and NTM Research Registry as reference standard, United States*.
| NTM case definition† | No. participants with diagnosis-based Medicare claim for NTM infection | PPV (95% CI)‡ | No. participants meeting BRR case definition for NTM infection§ | Sensitivity (95% CI)¶ |
|---|---|---|---|---|
| Primary definition: ICD-9-CM 031.0 | ||||
| All clinician-given codes# | 234 | 63.2 (57.1–69.4) | 226 | 69.9 (63.9–75.9) |
| ID specialist– and pulmonologist-given codes only | 205 | 65.4 (58.9–71.9) | 226 | 61.5 (55.2–67.9) |
| ID specialist–given codes only | 127 | 70.1 (62.1–78.0) | 226 | 39.8 (33.4–46.2) |
| Pulmonologist-given codes only |
133 |
60.9 (52.6–69.2) |
226 |
36.7 (30.4–43.0) |
| Secondary definition: ICD-9-CM 031.0, requiring a second 031.0 claim >30 d but <12 m of first claim | ||||
| All clinician-given codes | 122 | 72.1 (63.3–79.9) | 226 | 41.6 (35.2–48.0) |
| ID specialist– and pulmonologist-given codes only | 100 | 74.0 (64.3–82.3) | 226 | 33.2 (27.1–39.7) |
| ID specialist–given codes only | 45 | 82.2 (71.1–93.4) | 226 | 16.4 (11.6–21.2) |
| Pulmonologist-given codes only | 44 | 70.5 (57.0–83.9) | 226 | 13.3 (30.4–43.0) |
*BRR, Bronchiectasis and NTM Research Registry; NTM, nontuberculous mycobacteria; ICD-9-CM, International Classification of Disease, Ninth Version, Clinical Modification; ID, infectious disease; PPV, positive predictive value. †Only ICD-9-CM 031.0 code (pulmonary mycobacterial infection) was considered; other codes for NTM (031.8 [other specified mycobacterial diseases] and 031.9 [unspecified disease due to mycobacteria]) were not considered. ‡PPV for meeting a case definition for NTM infection in BRR within +12 months of first ICD-9-CM NTM code-cased claim (code 031.0). §NTM cases were identified in BRR on the basis of culture positivity on >1 respiratory specimen or antibiotic treatment for NTM during follow-up (a macrolide plus >1 antibiotic drugs). ¶Sensitivity for an ICD-9-CM NTM code–based claim within +12 months of meeting a case definition for NTM infection in BRR. #Clinician types include physicians, physician assistants, and nurse practitioners, excluding radiology or laboratory-associated claims.