title: Clinician compliance with laboratory monitoring and prescribing guidelines in HIV-1-infected patients receiving tenofovir.
abstract: BACKGROUND
  Tenofovir is part of the preferred first-line regimen for HIV-infected patients in South Africa (SA), but is associated with kidney toxicity. SA antiretroviral therapy (ART) guidelines recommend creatinine monitoring at baseline (ART start) and at 3, 6 and 12 months, and substituting tenofovir with zidovudine, stavudine or abacavir should creatinine clearance (CrCl) decrease to &lt;50 mL/min.
  
  
  OBJECTIVE
  To assess clinician compliance with tenofovir monitoring and prescribing guidelines.
  
  
  METHODS
  We described the proportion of adult patients on tenofovir-based first-line ART who were screened for baseline renal impairment, were monitored according to the SA antiretroviral treatment guidelines, and were switched from tenofovir if renal function declined.
  
  
  RESULTS
  We included 13 168 patients who started ART from 2010 to 2012. Creatinine concentrations were recorded in 11 712 (88.9%) patients on tenofovir at baseline, 9 135/11 657 (78.4%) at 3 months, 5 426/10 554 (51.4%) at 6 months, and 5 949/ 8 421 (70.6%) at 12 months. At baseline, 227 (1.9%) started tenofovir despite a CrCl &lt;50 mL/min. While on tenofovir, 525 patients had at least one CrCl of &lt;50 mL/min. Of 382 patients with ≥3 months' follow-up after a CrCl &lt;50 mL/min, 114 (29.8%) stopped tenofovir within 3 months. Clinicians were more likely to stop tenofovir in patients with lower CrCl and CD4 count. Of 226 patients who continued to receive tenofovir and had further CrCls available, 156 (69.0%) had a CrCl ≥50 mL/min at their next visit.
  
  
  CONCLUSIONS
  Creatinine monitoring is feasible where access to laboratory services is good. Kidney function recovered in most patients who continued to receive tenofovir despite a CrCl &lt;50 mL/min. Further research is needed to determine how best to monitor renal function with tenofovir in resource-limited settings.
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, South Africa. Mary-Ann.Davies@uct.ac.za.
authors.forename: Renee
authors.initials: R
authors.lastname: De Waal
authors.forename: Karen
authors.initials: K
authors.lastname: Cohen
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Fox
authors.forename: Kathryn
authors.initials: K
authors.lastname: Stinson
authors.forename: Gary
authors.initials: G
authors.lastname: Maartens
authors.forename: Andrew
authors.initials: A
authors.lastname: Boulle
authors.forename: Mary-Ann
authors.initials: MA
authors.lastname: Davies