CDC study highlights need for code to track new STI prevention tool

Doxycycline postexposure prophylaxis (doxy PEP) is now recommended by the CDC to help prevent bacterial STIs in certain high-risk groups, a prevention strategy that highlights the importance of monitoring uptake in routine care. A new study published in Sexually Transmitted Diseases finds that existing ICD-10 codes and prescribing data don’t reliably capture its use, pointing to the need for a dedicated code to track adoption and outcomes.

This study, led by researchers at the Centers for Disease Control and Prevention (CDC), used de-identified electronic health records from Truveta spanning 2018–2023. The analysis provides an early look at how doxy PEP prescriptions are documented in practice and whether current coding systems are sufficient for surveillance.

Study snapshot

• Population: 428,023 encounters among men aged 15–60 years with ICD-10 codes indicating higher risk for HIV or STI.
• Most common codes: 78.2% of records carried the code Z20.2 (exposure to infections with a predominantly sexual mode of transmission); 10.4% carried Z20.6 (exposure to HIV); 9.9% carried Z72.52 (high-risk homosexual behavior).
• Prescriptions: 16.1% of encounters were associated with a doxy PEP prescription within 14 days.
• Associated conditions: Doxy PEP prescriptions were often linked to non-STI indications, such as urinary symptoms or asthma, rather than codes clearly tied to STI prevention.

The authors conclude that existing ICD-10 codes are not sufficient to consistently identify doxy PEP prescriptions, making it difficult to monitor real-world adoption or outcomes.

Why real-world data matters

Randomized controlled trials have shown doxy PEP can reduce syphilis and chlamydia by more than 70% and gonorrhea by about 50%. These results led to for certain high-risk groups. Once guidelines are in place, the challenge shifts to understanding whether interventions are being adopted, and how well they can be tracked.

Real-world data (RWD) enable this level of visibility. Using Truveta Data — de-identified electronic health record (EHR) data from 1 in 3 Americans, refreshed daily and linked with claims, mortality, and social drivers of health — CDC researchers were able to examine how doxy PEP prescriptions are documented and demonstrate why a dedicated ICD-10 code is needed for monitoring.

Looking ahead

As new prevention strategies continue to emerge, high-quality real-world evidence will be central to tracking their uptake and evaluating their impact. The CDC’s study demonstrates how RWD can inform both clinical practice and public health policy, and why investments in timely, representative datasets are essential for regulatory and surveillance efforts.

See how Truveta Data supports regulatory and public health research.