A field evaluation of point-of-care creatinine testing within a large PrEP implementation program in Western Kenya.

To the Editors: Programmatic scale-up of preexposure prophylaxis (PrEP) is progressing with nearly 400,000 PrEP initiations worldwide as of October 2018.1 The World Health Organization (WHO) recommends creatinine (Cr) testing before starting PrEP, quarterly during PrEP use for the first 12 months, and then annually thereafter.2 This recommendation is based on labeling requirements that tenofovir disoproxil fumarate–based PrEP has to be used only in persons with normal renal function and rare experience with renal complications among HIV-infected persons using tenofovir disoproxil fumarate as part of HIV treatment. Initial PrEP trials all tested renal function using serum Cr before starting PrEP and at least quarterly during PrEP use.3–5 Abnormal renal function results were very rare in PrEP trials and generally returned to normal after stopping PrEP.6 In high-income settings, where laboratorybased Cr testing is widely available, PrEP programs have found low rates of ineligibility and discontinuation based on renal function and toxicity.7,8 In lowand middle-income countries (LMICs), PrEP programs are often located in decentralized settings without laboratory capacity to conduct Cr analysis; in such settings, Cr testing could be a barrier to PrEP initiation. In Kenya, the national PrEP guidelines recommend, but do not require, assessing creatinine clearance (CrCl) at PrEP initiation only if the clinic has laboratory capacity to do so.9 As programmatic PrEP delivery rolls out across LMICs with high HIV burden, it is unknown whether Cr testing is essential to assure safe PrEP use. Point-of-care (POC) machines could increase Cr testing accessibility, and previous evaluations have found feasibility in using validated POC Cr testing machines within LMICs for renal monitoring among obstetric patients and people living with HIV.10,11 To date, no study has systematically evaluated POC Cr testing within the context of programmatic PrEP delivery in LMICs. We evaluated feasibility and utility of POC Cr testing for PrEP initiation within a large PrEP implementation program in Western Kenya. From June 2017 to December 2018, HIV-uninfected women seeking routine antenatal care (ANC), postnatal care (PNC), and family planning (FP) services were screened per national PrEP guidelines at 16 facilities in Kisumu, Kenya, as part of the PrEP Implementation for Young Women and Adolescents (PrIYA) Program.12 Before PrEP initiation, nurses measured height and weight, conducted Cr serum testing using validated Xpress StatSensor POC machines (Nova Biomedical Cooperation, Waltham, MA),13 and estimated CrCl by the Cockcroft–Gault equation using a mobile application (MDCalc). 14 If a single estimated CrCl measurement was below the normal range (,50 mL/min according to Kenyan PrEP guidelines9), the test was repeated before excluding that client from PrEP services. Daily quality control checks were run on the StatSensor POC machines with high-, low-, and normal-range control substances. All control substances and StatSensor strips were stored in refrigerators procured and maintained by the program. In a subset, we evaluated CrCl results, the cost per test, and time to receive a result for the POC test compared with standard laboratory methods (Roche Cobas c111 Analyzer; Roche Diagnostics, Indianapolis, IN). 15 To perform the comparison, we conducted POC testing and laboratory methods on the same day among all women initiating PrEP at 1 facility over a 4-month period. Venous blood for laboratory testing was collected at the same time as POC testing. The Bland–Altman method was used to calculate the mean difference in estimated Cr between POC and laboratory-based measures.16 Overall, 4169 women interested in initiating PrEP were evaluated for PrEP medical eligibility and received POC Cr testing: 1680 (40.3%) from ANC, 2101 (50.4%) PNC, and 388 (9.3%) FP. The median age was 24 years [interquartile range (IQR) 21–28], and 205 (5%) women were aged 18 years younger. The overall median estimated CrCl was 99 mL/min (IQR 82–119): 113 mL/min (IQR 98–132) for ANC clients, 111 mL/min (IQR 93–130) for PNC, and 99 mL/min (IQR 82–120) for FP. Few women had estimated CrCl less than the CrCl cutoff for PrEP ineligibility of ,50 mL/min specified in the Kenyan national guidelines9: 8/4169 (0.2%) overall, 1 (0.06%) from ANC, 5 (0.2%) PNC, and 2 (0.5%) FP. Using a slightly higher CrCl cutoff of,60 mL/min,17 overall 122 (3%) women had an estimated CrCl ,60 mL/min, 4 (0.8%) from ANC, 91 (4.3%) PNC, and 17 (4.4%) FP. Among women with CrCl ,60 mL/min, the median age was 25 years (IQR 23–30), the median height 161 centimeters (IQR 157–165), the median weight 53 kilograms (IQR 47–60), and the median Cr 106 mmol/L (IQR 97–124). We compared estimated Cr and CrCl using duplicate POC and laboratory-based measures in a subset of women (n = 70) initiating PrEP within ANC (n = 34), PNC (n = 25) and FP clinics (n = 11). Among women with both POC and laboratory-based Cr results available (n = 70), the mean difference in estimated Cr between POC and laboratorybased tests from Bland–Altman validity The PrEP Implementation for Young Women and Adolescents (PrIYA) Program is funded by the United States Department of State as part of the DREAMS Innovation Challenge (Grant # 37188-1088 MOD01), managed by the JSI Research and Training Institute, Inc. The PrIYA Team was supported by the University of Washington’s Center for AIDS Research (CFAR) (P30 AI027757). This work was funded by a grant from the United States Department of State as part of PEPFAR’s DREAMS Partnership, managed by the JSI Research and Training Institute, Inc. (JSI). The opinions, findings, and conclusions stated in this article are those of the authors and do not necessarily reflect those of the United States Department of State or JSI. The authors have no conflicts of interest to disclose. 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