# Difficult-to-treat HIV in Sweden: a cross-sectional study

## TL;DR

This study examines the prevalence and outcomes of difficult-to-treat HIV in Sweden, finding that while 9% of patients fall into this category, most still achieve viral suppression.

## Contribution

The study introduces a classification system for difficult-to-treat HIV and compares treatment outcomes in a national cohort.

## Key findings

- Nine percent of the Swedish HIV cohort in 2023 had difficult-to-treat HIV.
- People with difficult-to-treat HIV had lower viral suppression rates (84% vs. 95%) and worse physical health.
- Advanced resistance and salvage therapy were rare in the current Swedish HIV cohort.

## Abstract

Our aim was to examine the prevalence and characteristics of difficult-to-treat HIV in the current Swedish HIV cohort and to compare treatment outcomes between people with difficult and non-difficult-to-treat HIV.

In this cross-sectional analysis of the Swedish HIV cohort, we identified all people with HIV currently in active care in 2023 from the national register InfCareHIV. We defined five categories of difficult-to-treat HIV: 1) advanced resistance, 2) four-drug regimen, 3) salvage therapy, 4) virologic failure within the past 12 months, and 5) ≥ 2 regimen switches following virologic failure since 2008. People classified as having difficult-to-treat HIV were compared with non-difficult for background characteristics as well as treatment outcomes (viral suppression and self-reported physical and psychological health).

Nine percent of the Swedish HIV cohort in 2023 (n = 8531) met at least one criterion for difficult-to-treat HIV. Most of them had ≥ 2 regimen switches (6%), and the other categories of difficult-to-treat HIV were rare (1–2% of the entire cohort). Compared with non-difficult, people with difficult-to-treat HIV were older, had an earlier first year of positive HIV test and lower CD4 counts, and were more often female. The viral suppression rate among people with difficult-to-treat HIV was 84% compared with 95% for non-difficult (p = 0.001). People with difficult-to-treat HIV reported worse physical (but not psychological) health, and this remained statistically significant after adjustment for age, sex, and transmission group.

Although 9% of the HIV cohort in Sweden in 2023 were classified as having difficult-to-treat HIV, a large proportion of these were virally suppressed, and challenges such as advanced resistance and need for salvage therapy are rare in the current Swedish cohort.