HIV Incidence Risk Index for MSM (HIRI-MSM) calculator

Clinical inputs

• Age today
• Number of male sex partners
• Receptive anal sex without a condom with a male partner, 1 or more times
• Number of HIV-positive male sex partners
• Insertive anal sex without a condom with an HIV-positive partner, 5 or more times
• Used amphetamines
• Used poppers (inhaled nitrites)

Primary source

Smith DK, Pals SL, Herbst JH, Shinde S, Carey JW. Development of a clinical screening index predictive of incident HIV infection among men who have sex with men in the United States. J Acquir Immune Defic Syndr. 2012;60(4):421-427. DOI: 10.1097/QAI.0b013e318256b2f6. PMID: 22487585. Abstract: the final index has age plus six behaviours in the prior 6 months (number of male sex partners, number of HIV-positive male partners, condomless receptive anal sex, condomless insertive anal sex with HIV-positive partners, poppers, amphetamines); scores range 0 to 47; a cutoff of 10 or more gave 84% sensitivity and 45% specificity; intended to prioritise people for intensive prevention such as PrEP. Point values as reprinted from Smith 2012 in Jones J et al., Assessing the performance of three HIV incidence risk scores in a cohort of Black and White MSM in the South, Sex Transm Dis 2017 (PMC5407317), Table 1: age 18-28 years 8, 29-40 years 5, 41-48 years 2, 49 years or older 0; more than 10 male partners 7, 6-10 partners 4, fewer than 6 partners 0; more than 1 HIV-positive male partner 8, exactly 1 partner 4, none 0; 1 or more episodes of condomless receptive anal sex with any male partner 10; 5 or more episodes of condomless insertive anal sex with an HIV-positive partner 6, fewer than 5 episodes 0; amphetamine use 5; poppers use 3. These points sum to the published maximum of 47, and the PubMed abstract of Smith 2012 confirms the seven items (age plus six behaviours including poppers and amphetamines) and the 0 to 47 range; the Smith 2012 full-text table itself was not openly readable, so the per-item points rest on the Jones 2017 reprint. Version used: the original 7-item Smith 2012 index. The CDC 2014 PrEP clinical providers' supplement (stacks.cdc.gov/view/cdc/23108) prints a modified six-item version (no poppers item, methamphetamine 6 points, same cutoff of 10) that is not used here. (2012)