Background
Timely diagnosis of HIV is crucial for effective treatment and prevention of transmission. In Thailand, despite advancements in HIV prevention and treatment, delays in diagnosis remain a significant challenge. We estimated delays in diagnosis (time from infection to diagnosis) and identified factors associated with the delay.
Methods
Data on newly reported treatment-naïve people living with HIV (PLHIV) ≥13 years diagnosed at 1,084 health units during 2014–2021 were obtained from Thailand’s National AIDS Program. We used CD4 depletion model to estimate the infection date using model parameters originally derived from the Concerted Action of Seroconversion to AIDS and Death in Europe Study (CASCADE) adjusted using published parameters from Asian population samples to account for differences in the rate of CD4 decline across HIV subtypes. We estimated time from infection to diagnosis by calculating the time difference between infection and diagnosis. We abstracted data on demographics, self-reported risk behaviors, dates of HIV testing, and dates and results of CD4 testing from HIV records. Multivariable linear regression analysis was used to identify factors influencing time from infection to diagnosis.
Results
Of 242,338 PLHIV, 201,752 (83.3%) had a baseline CD4 test within 6 months after diagnosis. Among those with baseline CD4 data, the median baseline CD4 count was 187 cells per µL (IQR 51–383). We estimate that among PLHIV diagnosed in 2021, the average time from infection to diagnosis was 5.7 years, 27% of them being diagnosed within a year of infection. The average delay in diagnosis in 2021 varied by age and population group with longer delays seen among 25–34-year-olds (6.2 years), 35-44-year-olds (6.7 years), men who inject drugs (9.4 years), and heterosexual men (6.6 years). The average time from infection to diagnosis and the percentage of those whose infection was diagnosed within 1 year remained stable over the analysis period. In multivariable analyses, factors associated with longer diagnosis delays were male sex, age 35-44 years, self-reported injection drug use, and being covered under universal health coverage (p<0.001).
Conclusions
Diagnosis delay varied by age and population group and showed no improvement from 2014 to 2021. Addressing the time from infection to diagnosis and the disparities across population groups may enhance overall public health outcomes and help end HIV as a public health threat.