Validation of Coding Algorithms for the Identification of Herpes Zoster among Children.
Year of Publication
2021 May 07
<p><strong>PURPOSE: </strong>To examine the validity of International Classification of Diseases, 10th Revision, (ICD-10) code-based algorithms for herpes zoster (HZ) in the electronic medical record (EMR) of a large, integrated pediatric healthcare network and to examine baseline demographics and chronic comorbidities associated with HZ in a representative pediatric population.</p>
<p><strong>METHODS: </strong>We reviewed the electronic charts of all patients with a single ICD-10 for HZ (B02.xx) as their primary or secondary diagnosis in the EMR of the Children's Hospital of Philadelphia (CHOP) healthcare network from January 2010 - March 2019. The positive predictive value (PPV) for a single code for HZ was calculated and alternative algorithms were examined to determine which method resulted in the highest PPV.</p>
<p><strong>RESULTS: </strong>The PPV for a single ICD-10 code was 91.7% (95% CI 80.8-95.4) for definitive and/or probable cases of HZ and 63.9% (95% CI 53.4-75.5%) for definitive cases alone. Adding a prescription for an antiviral did not improve the PPV. However, adding a new code for rash entered within 1 week of the HZ code increased the PPV to 100% for definitive and/or probable cases but with substantial loss of sensitivity. A high proportion of children with HZ who required inpatient hospitalization had chronic disease (70%) and were on systemic immunomodulatory therapy (50%).</p>
<p><strong>CONCLUSIONS: </strong>HZ can be identified with a high PPV in electronic medical records of children using ICD-10 code alone. These findings lay the foundation for future pharmacoepidemiologic research to better understand risk factors for HZ infection.</p>
Pharmacoepidemiol Drug Saf