Data from Africa showed an incidence of stage IV CKD of 7% in untreated patients after initiating antiretroviral therapy (using the

CG equation) [18] while the UK CHIC study reported a prevalence of stage V CKD of 0.31% (using the MDRD equations) [19]. To date, studies in HIV infection have used an extremely wide range of endpoints and methodologies. These include, but are not limited to, an eGFR<90 [1,20], <60 [17,20–27], <30 [18] or <15 mL/min/1.73 m2 [19], the rate of change in eGFR [18,21,24,28–32], a 20 [1], 25 [29] or 50% decline in eGFR [29], a 25% decrease in eGFR for those with an eGFR<60 mL/min/1.73 m2 [17,27],

a decline in eGFR of >3 mL/min/1.73 m2 per year [32], the rate of change in serum creatinine [33], and a 25% increase in [34] or doubling of serum creatinine [35]. Some studies check details have been cross-sectional [1,25], and some have used cystatin C to estimate eGFR rather than serum creatinine [32]. In some cases, although the 5-FU research buy study reports using the recommended classification system [13], CKD, however defined, is either not based on consecutive (i.e. confirmed values) measured at least 3 months apart or it is not clear whether or not this is the case [22,23,36,37]. Research into renal disease in HIV-infected persons is an expanding area and a welcome development for improving our understanding in this clinical area. Although there

is currently no consensus regarding which Fossariinae endpoint should be focused on, studies that focus on less advanced CKD, such as that by Tordato et al. [1], need to be interpreted with caution in light of the issues raised above and as the clinical relevance of such findings is not immediately clear. Risk factors for the development of less advanced CKD and outcomes in patients with small decreases in eGFR are likely to be different from those seen in patients with more advanced CKD, as are the likely interventions and management of these patients. As the field progresses, it will be useful to keep in mind the limitations of the available tools, for studies to consider a variety of sensitivity analyses using different endpoints or equations, and finally to work towards developing a common, useful, and clinically relevant endpoint. Such a common endpoint would help with identifying common risk factors and how these risk factors differ in different populations, facilitate appropriate interventions and enable changes over time or between patient populations to be monitored more easily.