Assessing the need for creating ICD-10 codes to enhance monitoring of doxycycline postexposure prophylaxis prescriptions in the United States

Background In 2024, the Centers for Disease Control and Prevention (CDC) recommended postexposure prophylaxis with doxycycline (doxy PEP) within 72 hours after sex for men who have sex with men (MSM) and other selected populations diagnosed with one or more bacterial sexually transmitted infections (STIs) within the past 12 months. To determine if doxy PEP prescriptions can be identified using existing International Classification of Diseases, Tenth Revision (ICD-10) codes, we assessed utilization of several ICD-10 codes that document sexual behaviors and doxycycline prescriptions using a large electronic health record (EHR) dataset. Methods We used 2018–2023 Truveta EHR data to analyze encounters indicating increased risk for HIV/ STI (ICD-10 codes: Z72.53 [high-risk bisexual behavior], Z72.52 [high-risk homosexual behavior], Z20.6 [exposure to HIV], Z20.2 [exposure to infections with a predominantly sexual mode of transmission], and Z29.81 [encounter for HIV preexposure prophylaxis]) among men aged 15–60 years and stratified by doxycycline prescription within 14 days of the encounter. Results Among 428,023 encounters coded for increased risk of HIV/STI among men aged 15–60 years, 78.2% were coded as Z20.2, followed by 10.4% as Z20.6, 9.9% as Z72.52, 1.2% as Z72.53, and 0.3% as Z29.81. The proportion of those encounters with doxycycline prescriptions was 16.1%. Among 68,891 encounters with doxycycline prescriptions, top five ICD-10 codes associated an STI syndrome were: symptoms of genitourinary system (R30–R39, 28.7%), diseases of urinary system (N30–N39, 9.9%), chlamydia (A74.9, 2.6%), gonorrhea (A54.9, 1.5%), syphilis (A53.9, 1.2%), and top one with a non-STI syndrome was asthma (J45, 5.9%). Conclusion Before CDC recommendations for doxy PEP, most encounters for potentially eligible patients were not explicitly among MSM, and doxycycline was prescribed broadly for various indications. A new ICD-10 code is needed for monitoring doxy PEP prescriptions with administrative data.