Sensitivity, specificity and predictive values of ICD-10 substance use codes in a cohort of substance use-related endocarditis patients

ABSTRACT

Background: Healthcare databases have the potential to become efficient tools for epidemiological research in People Who Inject Drugs (PWID). The validity of ICD-10 codes for specific substances in this population has not been assessed.

Objectives: Validate ICD-10 diagnosis codes relating to the use of specific substance classes in a cohort of endocarditis patients.

Methods: Our study sample consisted of 379 first-episode infective endocarditis patients (Male: 208, Female: 171), aged 18–55, admitted to any of three hospitals in London, Ontario from 2007 to 2018. Of these, 287 used drugs. We validated ICD-10 substance use codes for opioids (F11), stimulants (F15), cocaine (F14) and multiple substances (F19). Sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were calculated for each code, using self-reported substance use documented on medical record review as a gold standard. We conducted a comparative analysis between code-negative users and code-positive users for each substance.

Results: All substance use codes shared the same pattern: high specificity, high PPV and low sensitivity, with code F11 yielding the highest PPV (96.3%; 95% C.I.: 90.8–98.6) and sensitivity (42.6%; 95% C.I. 36.3–49.1). The code-positives and code-negatives for each substance did not differ significantly in any characteristics compared.

Conclusion: Our results suggest that the individual ICD-10 codes analyzed should not be used for research without adjustment for low sensitivity. However, due to high PPV and specificity, these codes may still have potential for research use. Because code-negative patients did not differ from code-positive patients, their data may be extrapolated to the overall group of substance users.

KEYWORDS:

• ICD-10 codes
• substance use
• infective endocarditis
• methamphetamines

Acknowledgement

Dr Susana Pearl for assistance with editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, YC. The data are not publicly available due to their containing information that could compromise the privacy of research participants.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website

Additional information

Funding

Y.C. 4500$ received from the Schulich School of Medicine and Dentistry through the Summer Research Training Program (SRTP).