Renal disease, treatment and outcomes

One thread at the conference was the outcomes of, and associations with, renal dysfunction.

In the D:A:D Study (abstract 865) 2.1% of the cohort developed an eGFR of less than 70 after a median follow-up of 4.5 years. The investigators identified that TDF, LPV/r and ATV (boosted in 75% of cases) were all associated with an incidence rate ratio (IRR) of approximately 1.1 per year of exposure for the development of an eGFR less than 70.  Switching off TDF was more common at eGFR levels between 60 and 70. Predictors of eGFR less than 70 were age, prior AIDS, current CD4 count, HCV or HBV coinfection and diabetes.

More data from the SMART study (abstract 866) were presented. This time eGFR and cystatin C levels were associated with mortality and other events in a sample of over 4000 subjects. They comment that cystatin C (a potential marker of GFR) may be affected by other issues in HIV infection and may not be an ideal marker of GFR in this population.

Others identified an independent association between renal impairment and cardiovascular events (abstract 868, from the ICONA cohort in Italy) and microalbuminuria in cART naive individuals and death (abstract 869).

In all, there is accumulating evidence that markers of renal dysfunction in the HIV infected population are likely to have similar prognostic significance as in the general population. This is worth discussing if people are considering whether to commence therapy above a CD4 count of 350 where a survival benefit has been convincingly demonstrated. The results from the START study are even more keenly awaited in light of these new data.