Late HIV diagnosis: An application of flexible Bayesian approaches to understand associated factors and time to diagnosis in Ireland, 2015–2024
12 affiliations
- 1HSE National Health Protection Office, Health Protection Surveillance Centre Dublin Ireland
- 2Health Protection Surveillance Centre Dublin Ireland
- 3Gay Men's Health Service Dublin Ireland
- 4HSE Sexual Health Programme Dublin Ireland
- 5School of Medicine Trinity College Dublin Dublin Ireland
- 6Department of Genitourinary Medicine and Infectious Diseases St James's Hospital Dublin Ireland
- 7HSE National Clinical Programme for Infectious Diseases Dublin Ireland
- 8School of Medicine University College Dublin Dublin Ireland
- 9Department of Infectious Diseases Mater Misericordiae University Hospital Dublin Ireland
- 10School of Public Health University College Cork Cork Ireland
- 11Department of Public Health HSE South West Cork Ireland
- 12INFANT Research Centre, University College Cork Cork Ireland
Abstract
Objectives: Late HIV diagnosis is associated with increased morbidity, mortality and onward transmission. The proportion diagnosed late reflects the combined effects of testing delays, incidence and migration, complicating its interpretation. We analysed national HIV surveillance data for Ireland (2015–2024) to understand the factors associated with late HIV diagnosis and testing delays.
Methods: We estimated prevalence ratios (PRs) for late diagnosis among new diagnoses using Bayesian logistic regression with marginal standardization. We investigated testing delays by estimating infection times and modelling truncation‐adjusted delay distributions with Bayesian lognormal regression. We conducted several sensitivity analyses for the main findings.
Results: Among 1551 included new HIV diagnoses with available information, 684 (44.1%) were late. This proportion exceeded 50% in several subgroups, including people aged over 50 years, people whose probable mode of transmission was heterosexual contact, and people born in sub‐Saharan Africa. Increasing age (adjusted PR per decade 1.20; 95% credible interval [CrI] 1.15–1.26) and heterosexual transmission (adjusted PR for heterosexual men vs. sex between men 1.43; 95% CrI 1.23–1.67) were associated with late diagnosis in both univariable and multivariable models. For in‐Ireland infections, median time from infection to diagnosis was estimated at 1.94 years (95% CrI 1.36–3.40), though this was particularly sensitive to modelling assumptions assessed in our sensitivity analyses, and the multivariable findings suggested longer time to diagnosis for men with heterosexual transmission in particular. For pre‐migration infections, median time from arrival to diagnosis was estimated at 0.60 years (95% CrI 0.47–0.83), and an estimated 50.5% of those diagnosed to date were late.
Conclusion: Late HIV diagnosis represents a significant challenge. Estimating time‐to‐diagnosis distributions may help separate the influence of testing delays from incidence and migration. The burden demonstrated across multiple groups highlights the need for normalization and expansion of HIV testing within and beyond traditional risk groups.
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BibTeX
@article{dowlingcullen2026late,
title = {{Late HIV diagnosis: An application of flexible Bayesian approaches to understand associated factors and time to diagnosis in Ireland, 2015–2024}},
author = {Cian Dowling‐Cullen and Katie O'Brien and Kate O'Donnell and Mary Archibald and Phil Downes and David Field and Caroline Hurley and Fiona Lyons and Eavan Muldoon and Peter Barrett and Cathal Walsh and Derval Igoe},
journal = {HIV Medicine},
year = {2026},
month = sep,
doi = {10.1111/hiv.70311},
url = {https://doi.org/10.1111/hiv.70311},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Late HIV diagnosis: An application of flexible Bayesian approaches to understand associated factors and time to diagnosis in Ireland, 2015–2024
AU - Cian Dowling‐Cullen
AU - Katie O'Brien
AU - Kate O'Donnell
AU - Mary Archibald
AU - Phil Downes
AU - David Field
AU - Caroline Hurley
AU - Fiona Lyons
AU - Eavan Muldoon
AU - Peter Barrett
AU - Cathal Walsh
AU - Derval Igoe
PY - 2026
DA - 2026/09/24
JO - HIV Medicine
DO - 10.1111/hiv.70311
UR - https://doi.org/10.1111/hiv.70311
AB - Objectives: Late HIV diagnosis is associated with increased morbidity, mortality and onward transmission. The proportion diagnosed late reflects the combined effects of testing delays, incidence and migration, complicating its interpretation. We analysed national HIV surveillance data for Ireland (2015–2024) to understand the factors associated with late HIV diagnosis and testing delays. Methods: We estimated prevalence ratios (PRs) for late diagnosis among new diagnoses using Bayesian logistic regression with marginal standardization. We investigated testing delays by estimating infection times and modelling truncation‐adjusted delay distributions with Bayesian lognormal regression. We conducted several sensitivity analyses for the main findings. Results: Among 1551 included new HIV diagnoses with available information, 684 (44.1%) were late. This proportion exceeded 50% in several subgroups, including people aged over 50 years, people whose probable mode of transmission was heterosexual contact, and people born in sub‐Saharan Africa. Increasing age (adjusted PR per decade 1.20; 95% credible interval [CrI] 1.15–1.26) and heterosexual transmission (adjusted PR for heterosexual men vs. sex between men 1.43; 95% CrI 1.23–1.67) were associated with late diagnosis in both univariable and multivariable models. For in‐Ireland infections, median time from infection to diagnosis was estimated at 1.94 years (95% CrI 1.36–3.40), though this was particularly sensitive to modelling assumptions assessed in our sensitivity analyses, and the multivariable findings suggested longer time to diagnosis for men with heterosexual transmission in particular. For pre‐migration infections, median time from arrival to diagnosis was estimated at 0.60 years (95% CrI 0.47–0.83), and an estimated 50.5% of those diagnosed to date were late. Conclusion: Late HIV diagnosis represents a significant challenge. Estimating time‐to‐diagnosis distributions may help separate the influence of testing delays from incidence and migration. The burden demonstrated across multiple groups highlights the need for normalization and expansion of HIV testing within and beyond traditional risk groups.
SN - 1464-2662
SN - 1468-1293
ER -