Risk of death in UK after diagnosis of 3-class resistance

An analysis from Deenan Pillay on behalf of the UK Collaborative HIV Cohort Study (UK-CHIC) evaluated predictors of survival after diagnosis with multi-drug resistance (MDR). Of 628 patients 54 (9%) died within two years of their MDR diagnosis, defined as at least one primary mutation to nucleosides, NNRTIs and PIs. The cohort was 85% male, median age 43, with a median CD4 at MDR diagnosis of 238 cells/mm3 (IQR 110-376). This rose to 13% at three years. though far fewer patients had this length of follow-up.

The study was primarily looking at response to strategies including staying on the same treatment, switching to a treatment with the same, higher, or lower genotypic sensitivity score (GSS) or stopping treatment (with the same or a reduced GSS). Compared to staying on the same treatment, switching to a regimen with a lower GSS score increased the risk of death (RR 1.4 [0.17, 13.0]) while switching to a regimen with a high GSS (RR 0.31, [0.11, 0.89]) or even the same GSS (RR 0.35, [0.16, 0.80]) was protective.

There are several important factors to remember when looking at these results. Firstly, the majority of patients with 2-year follow-up in this cohort were diagnosed with MDR between in 1999, 2000 or 2001 (26% 29% and 20% respectively). The subsequent period was therefore prior to the availability to T-20 and tipranavir. The analysis didnt look at role of individual drugs used in either the maintained or switched combinations, nor the effect of several changes in treatment.

Although success rates to treatment are generally improving, a small percentage are likely to accumulate resistance, and this study provided a sobering reminder of the clinical impact of resistance. Prevalence of MDR in the UK is steady at 4% of patients, although the increasing number of people on treatment mean that absolute numbers are increasing.

Grover D, Allen L, Pillay D et al. Predictors of death, and response to therapy in patients with multi(three)-class drug resistant HIV in the UK. 14th International HIV Drug Resistance Workshop (14th IHDRW), 7-11 June 2005, Quebec City, Canada. Abstract 5. Antiviral Therapy 2005; 10:S7.