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Volume 27, Number 3—March 2021
Research Letter

Validity of Diagnosis Code–Based Claims to Identify Pulmonary NTM Disease in Bronchiectasis Patients

Jennifer H. KuComments to Author , Emily M. Henkle, Kathleen F. Carlson, Miguel Marino, and Kevin L. Winthrop
Author affiliations: Oregon Health & Science University–Portland State University School of Public Health, Portland, Oregon, USA (J.H. Ku, E.M. Henkle, K.F. Carlson, M. Marino, K.L. Winthrop); Veterans Affairs Portland Healthcare System, Portland (K.F. Carlson)

Main Article


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
60.9 (52.6–69.2)
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.

Main Article

Page created: November 02, 2020
Page updated: February 22, 2021
Page reviewed: February 22, 2021
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