Antiretroviral therapy dose adjustments based on calculated creatinine clearance

Whereas therapy for HIV is dependent on level of creatinine clearance, most laboratories locally only report an absolute creatinine value. There is likelihood that the patients already on antiretroviral therapy (ART) may have required dosage adjustment at the time of initiation of therapy or sometime during ongoing therapy. This paper explores a group of patients who are already on ART to determine their creatinine clearance and assess the need for ART dose adjustment.

To determine the proportion of stable HIV outpatients who have a documented creatinine clearance (CrCI) and the proportion requiring antiretroviral drug dose adjustments depending on their creatinine clearance.

Retrospective observational study.

One stop HIV medical clinic, Aga Khan University Hospital, Nairobi between January and February 2007.

Ninety three patients seen.

None of the study subjects had a calculated creatinine clearance in their medical records. Fifteen of the 93 patients (16.1%) had no serum creatinine performed in the twelve months preceding the last clinic visit. Nine of the remaining 78 patients (11.5%) had evidence of renal insufficiency (CrCI <60mls/min) as estimated by the Cockroft Gault method, with six patients (7.7%) requiring dose adjustments to the one or more drugs in their antiretroviral therapy (ART) regime (CrCI <50mls/min).

It is imperative to have a CrCI prior to and during follow up of patients with HIV disease on ART to reduce potential drug toxicities and interactions, especially with the increased utilisation of newer and potentially more nephrotoxic antiretrovirals.