# ICD-10 Codes to Identify Adverse Drug Events Associated with Antibiotics in Administrative Data

## TL;DR

This paper describes a method to identify adverse drug events linked to antibiotics using hospital diagnostic codes, helping track antibiotic-related harms in healthcare data.

## Contribution

A novel methodology for developing and validating ICD-10 codes to identify antibiotic-associated adverse drug events in administrative data.

## Key findings

- 72 ICD-10 codes were classified as likely antibiotic-associated.
- Inter-rater reliability was assessed using Kappa scores with 95% confidence intervals.
- The code list can improve capturing antibiotic-related adverse events in administrative data.

## Abstract

Antibiotics are among the most used therapeutics in primary care, and while their benefits are clear, the potential harms related to adverse drug events (ADEs) cannot be ignored. We outline the creation of a comprehensive list of diagnostic codes describing antibiotic-associated ADEs resulting in presentations to acute care hospitals. Methods: Previously published ADE codes were used to link BC hospitalizations to prior outpatient antibiotic prescriptions and were restricted based on whether patients received an antibiotic within a month prior to the ADE-related hospitalization. The code list was reviewed by two clinical experts independently for the likelihood of being antibiotic-associated. The inter-rater reliability was calculated using Kappa scores with 95% confidence intervals (CIs). Results: Of the 695 ICD-10 ADE codes with evidence of recent antibiotic administration, 72, 68, and 555 codes were considered likely, possibly, and unlikely antibiotic-associated, respectively. Conclusions: We outline a methodology for developing an ICD-10 code list for antibiotic-associated ADEs severe enough to warrant hospital admission. This will help to improve the use of administrative data to capture antibiotic-associated ADEs.