Table 1.
Patient characteristics of Groups I–IV.
Figure 1.
Antiretroviral drug use in Sweden 1987–2011.
The graphs depict the proportion of patients on ART exposed to each individual drug per calendar year, revealing trends in usage prevalence overtime.
Table 2.
Drug exposure among the four patient groups I–IV.
Figure 2.
Differences in first line ART combinations over time.
The coloured bars show the total number of patients in groups I–IV who initiated different kinds of first line ART: 1 NRTI only; 2 NRTIs; 2 NRTIs +1 (unboosted) PI, 2 NRTIs +1 boosted PI, 2 NRTIs +1 NNRTI or Other combination (for example 3 NRTIs, 3 NRTIs +1 PI or 1 NNRTI, 1 NRTI +1 PI +1 NNRTI or combinations including new drug classes).
Figure 3.
Prevalence of major resistance mutations among all ART-experienced patients 1997–2011.
The coloured graphs show the proportion of patients on treatment each year that had at least one major drug resistance mutation in that year. Any DRM includes all patients with at least one major resistance mutation to any drug class while separate graphs show the prevalence of ≥1 mutation associated with resistance to NRTI, NNRTI and PI respectively. The black line illustrates the total number of Swedish HIV-patients on ART each calendar year.
Figure 4.
Resistance by year of first ART.
These graphs show the level of resistance in each given year by the four groups, I–IV. This aims to show the composition of resistance over time, where patients with early exposure to ART (groups I and II) constitute the vast majority of resistance cases. Even in recent years, most resistance is found among these patients although they comprise a relatively small portion of the total number of patients on ART (group I patients corresponded to just 18% of patients on ART in 2011). Important differences can be noted between drug classes, where group IV patients contribute to a substantial proportion of recent NNRTI mutations while hardly any PI mutations have been found in this group.
Figure 5.
Prevalence trends of individual resistance mutations 1997–2011.
Prevalence of the most common resistance mutations in relation to all performed GRTs per calendar year. All NRTI, PI and NNRTI associated mutations with a prevalence of at least 5% of GRTs any year have been included.
Figure 6.
Prevalence of M184IV and K103N by drug exposure.
The prevalence of M184IV was divided into patients who had been exposed to 3TC but not FTC (3TC only), FTC but not 3TC (FTC only); or both 3TC and FTC (the graphs show % of GRTs on patients from each group that contained the mutation). No difference could be detected between 3TC only and FTC only, while the patients with exposure to both drugs were more likely to carry resistant virus. In the corresponding graph for K103N it is shown that patients exposed to EFV consistently had higher mutation prevalence compared to patients with NVP. The limited number of patients with exposure to both EFV and NVP had intermediate values and are omitted for clarity.
Figure 7.
Full-class resistance to one or several classes 1997–2011.
Percentage of GRTs containing virus that is fully resistant to one or more drug classes. Full-class resistance (FCR) was defined as intermediate or high-level resistance to all drugs in the class that were available in Sweden that year. In addition, for NRTI, wide-class resistance (WCR) prohibiting the use of an effective 2 NRTI backbone is shown (blue dashed line). The black dashed line shows total resistance prohibiting efficient use of any standard regimen (2 compatible NRTIs +1 PI or 1 NNRTI).