Precision of tuberculosis diagnosis codes in the Central Denmark Region

Victor Næstholt Dahl; Pernille Grand Moestrup; Anders Koch; Dorte Bek Folkvardsen; Frauke Rudolf; Tina Nørregaard Gissel; Andreas Fløe

doi:10.61409/A12240847

Precision of tuberculosis diagnosis codes in the Central Denmark Region

Victor Næstholt Dahl^*, Pernille Grand Moestrup, Anders Koch, Dorte Bek Folkvardsen, Frauke Rudolf, Tina Nørregaard Gissel, Andreas Fløe

^*Corresponding author for this work

Department of Infectious Diseases

Abstract

INTRODUCTION: Correct use of tuberculosis (TB) diagnosis codes is essential for patient care, surveillance and resource allocation. We aimed to assess the positive predictive value (PPV) of TB diagnosis codes.

METHODS: In this retrospective cohort study, we identified patients with International Classification of Diseases, tenth version (ICD-10) TB diagnosis codes from 1 July 2020 to 30 June 2023, at two TB centres in the Central Denmark Region. Confirmed TB was defined as microbiologically confirmed TB, prescription of ≥ 3 first- or second-line TB drugs, or TB notification. All patients who did not meet these criteria and those who received fewer than three TB drugs or lacked TB notification underwent manual hospital record review to verify or exclude the TB diagnosis. PPVs were calculated as the proportion of confirmed TB diagnoses among all patients with a TB diagnosis code.

RESULTS: In total, 185/230 patients were confirmed to have TB, yielding a PPV of 80% (95% CI: 75; 85). The PPVs for TB microbiology, TB prescriptions and TB notification exceeded 95% individually. Excluding TB lupus codes increased the PPV to 89% (95% CI: 84; 93). Patients with more than one different type of TB diagnosis code had a PPV of 100% (95% CI: 93; 100). Additionally, PPVs were high when TB diagnosis codes appeared on multiple occasions, increasing with the number of occurrences (≥ 2: 85%, ≥ 3: 89%, ≥ 4: 93%).

CONCLUSION: TB ICD-10 diagnosis codes demonstrate a moderately high PPV in Denmark, particularly when excluding TB lupus codes, highlighting the importance and complexities of diagnostic coding.

FUNDING: None.

TRIAL REGISTRATION: Not relevant.

Original language	English
Article number	A12240847
Journal	Danish Medical Journal
Volume	72
Issue number	7
ISSN	1603-9629
DOIs	https://doi.org/10.61409/A12240847
Publication status	Published - 12 Jun 2025

Keywords

Humans
Denmark/epidemiology
Retrospective Studies
Tuberculosis/diagnosis
Female
International Classification of Diseases/standards
Male
Middle Aged
Adult
Aged
Predictive Value of Tests
Antitubercular Agents/therapeutic use

Access to Document

10.61409/A12240847Licence: CC BY-NC-ND

Cite this

@article{ce44b87be3684fd09057714a01331492,

title = "Precision of tuberculosis diagnosis codes in the Central Denmark Region",

abstract = "INTRODUCTION: Correct use of tuberculosis (TB) diagnosis codes is essential for patient care, surveillance and resource allocation. We aimed to assess the positive predictive value (PPV) of TB diagnosis codes.METHODS: In this retrospective cohort study, we identified patients with International Classification of Diseases, tenth version (ICD-10) TB diagnosis codes from 1 July 2020 to 30 June 2023, at two TB centres in the Central Denmark Region. Confirmed TB was defined as microbiologically confirmed TB, prescription of ≥ 3 first- or second-line TB drugs, or TB notification. All patients who did not meet these criteria and those who received fewer than three TB drugs or lacked TB notification underwent manual hospital record review to verify or exclude the TB diagnosis. PPVs were calculated as the proportion of confirmed TB diagnoses among all patients with a TB diagnosis code.RESULTS: In total, 185/230 patients were confirmed to have TB, yielding a PPV of 80\% (95\% CI: 75; 85). The PPVs for TB microbiology, TB prescriptions and TB notification exceeded 95\% individually. Excluding TB lupus codes increased the PPV to 89\% (95\% CI: 84; 93). Patients with more than one different type of TB diagnosis code had a PPV of 100\% (95\% CI: 93; 100). Additionally, PPVs were high when TB diagnosis codes appeared on multiple occasions, increasing with the number of occurrences (≥ 2: 85\%, ≥ 3: 89\%, ≥ 4: 93\%).CONCLUSION: TB ICD-10 diagnosis codes demonstrate a moderately high PPV in Denmark, particularly when excluding TB lupus codes, highlighting the importance and complexities of diagnostic coding.FUNDING: None.TRIAL REGISTRATION: Not relevant.",

keywords = "Humans, Denmark/epidemiology, Retrospective Studies, Tuberculosis/diagnosis, Female, International Classification of Diseases/standards, Male, Middle Aged, Adult, Aged, Predictive Value of Tests, Antitubercular Agents/therapeutic use",

author = "Dahl, \{Victor N{\ae}stholt\} and Moestrup, \{Pernille Grand\} and Anders Koch and Folkvardsen, \{Dorte Bek\} and Frauke Rudolf and Gissel, \{Tina N{\o}rregaard\} and Andreas Fl{\o}e",

note = "Published under Open Access CC-BY-NC-BD 4.0. https://creativecommons.org/licenses/by-nc-nd/4.0/.",

year = "2025",

month = jun,

day = "12",

doi = "10.61409/A12240847",

language = "English",

volume = "72",

journal = "Danish Medical Journal",

issn = "1603-9629",

publisher = "Almindelige Danske Laegeforening",

number = "7",

}

TY - JOUR

T1 - Precision of tuberculosis diagnosis codes in the Central Denmark Region

AU - Dahl, Victor Næstholt

AU - Moestrup, Pernille Grand

AU - Koch, Anders

AU - Folkvardsen, Dorte Bek

AU - Rudolf, Frauke

AU - Gissel, Tina Nørregaard

AU - Fløe, Andreas

N1 - Published under Open Access CC-BY-NC-BD 4.0. https://creativecommons.org/licenses/by-nc-nd/4.0/.

PY - 2025/6/12

Y1 - 2025/6/12

N2 - INTRODUCTION: Correct use of tuberculosis (TB) diagnosis codes is essential for patient care, surveillance and resource allocation. We aimed to assess the positive predictive value (PPV) of TB diagnosis codes.METHODS: In this retrospective cohort study, we identified patients with International Classification of Diseases, tenth version (ICD-10) TB diagnosis codes from 1 July 2020 to 30 June 2023, at two TB centres in the Central Denmark Region. Confirmed TB was defined as microbiologically confirmed TB, prescription of ≥ 3 first- or second-line TB drugs, or TB notification. All patients who did not meet these criteria and those who received fewer than three TB drugs or lacked TB notification underwent manual hospital record review to verify or exclude the TB diagnosis. PPVs were calculated as the proportion of confirmed TB diagnoses among all patients with a TB diagnosis code.RESULTS: In total, 185/230 patients were confirmed to have TB, yielding a PPV of 80% (95% CI: 75; 85). The PPVs for TB microbiology, TB prescriptions and TB notification exceeded 95% individually. Excluding TB lupus codes increased the PPV to 89% (95% CI: 84; 93). Patients with more than one different type of TB diagnosis code had a PPV of 100% (95% CI: 93; 100). Additionally, PPVs were high when TB diagnosis codes appeared on multiple occasions, increasing with the number of occurrences (≥ 2: 85%, ≥ 3: 89%, ≥ 4: 93%).CONCLUSION: TB ICD-10 diagnosis codes demonstrate a moderately high PPV in Denmark, particularly when excluding TB lupus codes, highlighting the importance and complexities of diagnostic coding.FUNDING: None.TRIAL REGISTRATION: Not relevant.

AB - INTRODUCTION: Correct use of tuberculosis (TB) diagnosis codes is essential for patient care, surveillance and resource allocation. We aimed to assess the positive predictive value (PPV) of TB diagnosis codes.METHODS: In this retrospective cohort study, we identified patients with International Classification of Diseases, tenth version (ICD-10) TB diagnosis codes from 1 July 2020 to 30 June 2023, at two TB centres in the Central Denmark Region. Confirmed TB was defined as microbiologically confirmed TB, prescription of ≥ 3 first- or second-line TB drugs, or TB notification. All patients who did not meet these criteria and those who received fewer than three TB drugs or lacked TB notification underwent manual hospital record review to verify or exclude the TB diagnosis. PPVs were calculated as the proportion of confirmed TB diagnoses among all patients with a TB diagnosis code.RESULTS: In total, 185/230 patients were confirmed to have TB, yielding a PPV of 80% (95% CI: 75; 85). The PPVs for TB microbiology, TB prescriptions and TB notification exceeded 95% individually. Excluding TB lupus codes increased the PPV to 89% (95% CI: 84; 93). Patients with more than one different type of TB diagnosis code had a PPV of 100% (95% CI: 93; 100). Additionally, PPVs were high when TB diagnosis codes appeared on multiple occasions, increasing with the number of occurrences (≥ 2: 85%, ≥ 3: 89%, ≥ 4: 93%).CONCLUSION: TB ICD-10 diagnosis codes demonstrate a moderately high PPV in Denmark, particularly when excluding TB lupus codes, highlighting the importance and complexities of diagnostic coding.FUNDING: None.TRIAL REGISTRATION: Not relevant.

KW - Humans

KW - Denmark/epidemiology

KW - Retrospective Studies

KW - Tuberculosis/diagnosis

KW - Female

KW - International Classification of Diseases/standards

KW - Male

KW - Middle Aged

KW - Adult

KW - Aged

KW - Predictive Value of Tests

KW - Antitubercular Agents/therapeutic use

UR - https://www.scopus.com/pages/publications/105010287652

U2 - 10.61409/A12240847

DO - 10.61409/A12240847

M3 - Journal article

C2 - 40600676

SN - 1603-9629

VL - 72

JO - Danish Medical Journal

JF - Danish Medical Journal

IS - 7

M1 - A12240847

ER -

Precision of tuberculosis diagnosis codes in the Central Denmark Region

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this