Management of abnormal screening tests

If a patient’s baseline screening tests or clinical assessment demonstrate an abnormality, underlying reasons for renal disease should be sought. Further investigation of the aetiology of renal impairment may be required, and referral to a Nephrologist is recommended if there is CKD, significant proteinuria, haematuria or difficult-to-control hypertension²⁹. Referral to a Nephrologist should also be considered for patients after the commencement of ART with the development of any of these features, as well as those patients with progressively declining renal function, or in the setting of the clinical suspicion of ART-related nephrotoxicity^21,29,30.

A patient’s risk of developing kidney disease should also be evaluated and modifiable risk factors addressed. The close association between renal and cardiovascular disease mandates that the patient’s risk of cardiovascular disease should also be addressed in those at risk and in those with abnormal baseline screening tests²⁹. Management approaches include lifestyle modification, such as weight loss and smoking cessation. As well, pharmacological control of hypertension with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB) should be commenced, especially if there is proteinuria at baseline. Other modifiable risk factors which should be addressed include dyslipidaemia and hyperglycaemia³¹. Some improvement in renal function and proteinuria has been described after commencing ART³². Other specific therapy may be required, depending on the aetiology of the patient’s renal disease. These therapies are usually commenced by a Nephrologist.

Consideration should also be given to the identification of any reversible factors, such as the cessation of nephrotoxic medications, and attention should be paid to dose adjustment of medications excreted through the kidneys³³.  An important consideration is the renal profile of ART and the renal risk factors of an individual patient. In most circumstances, potentially nephrotoxic antiretroviral drugs should be avoided if a patient is at very high risk of renal disease or has established renal disease at baseline³⁴.  Importantly, all patients with HIV-infection, regardless of type of ART used, remain at risk of CKD and should be routinely screened for clinical risk factors and for the presence of CKD.

Specific renal disorders in patients with HIV infection

The aetiology of renal disease in HIV-infected patients may be related to the HIV infection itself or, more commonly, be a manifestation of NICMs or an adverse effect of ART³⁴.  Acute kidney injury of any aetiology is associated with an increased risk of CKD in the longer-term³⁵.  To differentiate with certainty between the wide-range of different renal pathologies that are possible in HIV-infected patients, a renal biopsy may be indicated, although, even with a renal biopsy it can be difficult to absolutely attribute the causation of HIV infection in the pathological features demonstrated³⁶. A useful classification system of the aetiology of renal disease in HIV infection is based on the predominant tissue compartment affected by the renal pathology; glomerular, tubulointerstitial, vascular or other, as shown in Table 2³⁷.

Table 2. Classification of HIV-associated renal pathology based on predominant tissue compartment affected. (adapted from Swanepoel et al ³⁷)