Coding Long COVID: Characterizing a new disease through an ICD-10 lens

Area of Science:

• Medical Informatics
• Public Health
• Epidemiology

Background:

• The naming and coding of new diseases like Long COVID (Post-Acute Sequelae of SARS-CoV-2 infection) present challenges, with diagnostic codes often lagging behind clinical recognition.
• The ICD-10-CM code U09.9 for "Post COVID-19 condition, unspecified" was implemented in the US nearly two years after patient-reported symptoms emerged.

Approach:

• Utilized the largest publicly available HIPAA-limited dataset of US COVID-19 patients (n=21,072) with a U09.9 diagnosis.
• Analyzed patient demographics, social determinants of health, co-occurring diagnoses (clustered via Louvain algorithm), and associated medications/procedures.
• Stratified analyses by age group to identify lifespan-specific care patterns.

Key Points:

• Co-occurring diagnoses for U09.9 clustered into cardiopulmonary, neurological, gastrointestinal, and comorbid categories.
• Patients with U09.9 diagnoses were demographically skewed: predominantly female, White, non-Hispanic individuals in areas with low poverty, high education, and good healthcare access.
• Characterized common medications and procedures linked to U09.9 coding.

Conclusions:

• The study provides insights into potential Long COVID subtypes and current clinical practice patterns.
• Significant disparities exist in the diagnosis and potentially the care of Long COVID patients, necessitating urgent attention and further investigation.