Value of Cystatin C-Based e-GFR Measurements to Predict Long-Term Tenofovir Nephrotoxicity in Patients With Hepatitis B. Am J Ther. 2019;26:e25-e31. [PMID: 27753647 DOI: 10.1097/mjt.0000000000000518]

Comparison of renal safety and bone mineral density of tenofovir and entecavir in patients with chronic hepatitis B: A Systematic Review and Meta-analysis

OBJECTIVE

Tenofovir disoproxil fumarate (TDF) and entecavir (ETV) are recommended as first-line treatments for chronic hepatitis B (CHB). However, the safety of these two drugs remains controversial. This study aims to evaluate and compare renal function and bone mineral density in CHB patients who took TDF or ETV.

METHODS

The electronic databases of the Cochrane Library, PubMed, and Embase were searched. The key words were: "CHB," "tenofovir," and "entecavir". Heterogeneity and subgroups were analyzed.

RESULTS

16 studies met the inclusion criteria. There was no significant difference in serum creatinine levels between the TDF and the ETV group. There was a significant standardized mean difference in serum estimated glomerular filtration rate (eGFR) between months (12 months: SMD [95%CI] = -0.07 [-0.12, -0.01]; 18-24 months: SMD [95%CI]=-0.11[-0.17],-0.05]), but no significant difference emerged in the long-term drug use for over 24 months. There was no significant difference in the incidence of osteopenia/osteoporosis (I²=41%, RR [95%CI]=1.29[0.93,1.77], p=0.13>0.05).

CONCLUSIONS

Compared with the ETV group, a greater reduction in eGFR and serum phosphorus levels was observed in the TDF group. There was no significant difference in the incidence of osteopenia/osteoporosis between the two groups.

Long-term renal safety between patients with chronic hepatitis B receiving tenofovir vs. entecavir therapy: A multicenter study

Renal safety is a critical issue in chronic hepatitis B (CHB) patients receiving long-term entecavir (ETV) or tenofovir disofuroxil fumarate (TDF) therapy. We investigated their effects on estimated glomerular filtration rate (eGFR). Treatment-naive CHB patients receiving ETV or TDF for ≥1 year were recruited. The eGFR was assessed using the Chronic Kidney Disease Epidemiology Collaboration equation. We calculated average annual percent change (AAPC) in eGFR using Joinpoint regression. At the beginning of the observation, the ETV group had more unfavorable conditions than the TDF group: lower eGFR and higher FIB-4 and APRI than the TDF group (all p < .001). After 6 years of antiviral therapy, the mean eGFR in the ETV group (n = 1793) was maintained (96.0 at first year to 95.6 ml/min/1.73 m2 at sixth year; AAPC -0.09%; p = .322), whereas that in the TDF group (n = 1240) significantly decreased annually (101.9 at first year to 96.9 ml/min/1.73 m2 at sixth year; AAPC -0.88%; p < .001). Notably, in the TDF group, even patients without diabetes (AAPC -0.80%; p = 0.001) or hypertension (AAPC -0.87%; p = .001) experienced significant decrease in eGFR. Expectably, accompanying diabetes (AAPC -1.59%; p = .011) or hypertension (AAPC -1.00%; p = .002) tended to accelerate eGFR decrease. TDF treatment (odds ratio 1.66, p < .001), along with eGFR<60 ml/min/1.73 m2 , serum albumin<3.5 mg/dl, and hypertension, were independently associated with ongoing renal dysfunction, defined as a negative slope of the mean eGFR change. In conclusion, compared with ETV, long-term TDF treatment induced slow, but progressive renal dysfunction. Although the annual eGFR change by TDF was small, careful monitoring is necessary, especially in patients requiring life-long therapy.

Pathway Association Studies Reveal Gene Loci and Pathway Networks that Associated With Plasma Cystatin C Levels

As a marker for glomerular filtration, plasma cystatin C level is used to evaluate kidney function. To decipher genetic factors that control the plasma cystatin C level, we performed genome-wide association and pathway association studies using United Kingdom Biobank data. One hundred fifteen loci yielded p values less than 1 × 10⁻¹⁰⁰, three genes (clusters) showed the most significant associations, including the CST8-CST9 cluster on chromosome 20, the SH2B3-ATXN2 gene region on chromosome 12, and the SHROOM3-CCDC158 gene region on chromosome 4. In pathway association studies, forty significant pathways had FDR (false discovery rate) and or FWER (family-wise error rate) ≤ 0.001: spermatogenesis, leukocyte trans-endothelial migration, cell adhesion, glycoprotein, membrane lipid, steroid metabolic process, and insulin signaling pathways were among the most significant pathways that associated with the plasma cystatin C levels. We also performed Genome-wide association studies for eGFR, top associated genes were largely overlapped with those for cystatin C.

Is urinary β2-microglobulin a reliable marker for assessment of renal tubular dysfunction in chronic hepatitis B patients receiving tenofovir therapy?

BACKGROUND AND AIM

Urinary β2-microglobulin (β2-M) is a marker for renal tubular dysfunction. The current study aimed to assess urinary β2-M as a reliable marker for early prediction of tenofovir disoproxil fumarate (TDF)-related nephrotoxicity among hepatitis B virus (HBV) patients.

METHODS

Forty-two HBV patients who were a candidate for TDF therapy or have recently started it (for less than 6 months) were enrolled and subjected to demographic, clinical, laboratory assessment, abdominal ultrasound and transient elastography. The glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault equation. Also, urinary β2-M was measured by the ELISA method within 6 months after the introduction of TDF treatment and 6 months later.

RESULTS

Mean age was 41.8 (9.55) years, 27 were males and 59.5% of patients have elevated urinary β2-M after 6 months follow-up of TDF therapy. Urinary β2-M was 0.07 ± 0.07 μg/ml at baseline and insignificantly increased up to 0.09 ± 0.08 μg/ml after 6 months follow-up. Despite the insignificant increase in serum creatinine from 0.85 ± 0.23 mg/dl at baseline to 0.9 ± 0.21 mg/dl after 6 months and the insignificant decrease in eGFR from 126.2 ± 39.72 ml/min at baseline and 117.64 ± 42.23 ml/min at 6 months follow-up. No correlation was found between the changes in urinary β2-M and the changes in other renal function indices at baseline and 6 months follow-up.

CONCLUSIONS

Short-term TDF therapy is associated with nonsignificant changes either in eGFR or urinary β2-M; these changes are not clinically relevant that indicates disease progression. Therefore, the suitability of urinary β2-M as a screening tool for tenofovir induced tubular dysfunction should be further.

Comparison of renal safety of tenofovir and entecavir in patients with chronic hepatitis B: Systematic review with meta-analysis

BACKGROUND

Recently, the American Association for the Study of Liver Disease suggested no preference between tenofovir (TDF) and entecavir (ETV) regarding potential long-term risks of renal complications. Over the years, renal safety has become a critical concern in nucleos(t)ide analog-treated patients due to the long-term use of these drugs. However, existing studies do not show significant differences in renal dysfunction between these two drugs. Further, there is a paucity of studies comparing the long-term renal effects of TDF and ETV.

AIM

To investigate the effects of TDF and ETV on renal function, we performed systematic review and meta-analysis.

METHODS

Two investigators independently searched the Cochrane Library, MEDLINE, and Embase databases for randomized controlled trials and nonrandomized studies (NRSs) using the keywords “CHB”, “Tenofovir”, and “Entecavir”, and additional references were obtained from the bibliographies of relevant articles published through December 2017. The quality of each study was assessed using the Newcastle-Ottawa scale and the Grading of Recommendations Assessment, Development and Evaluation criteria. The primary outcome was the change in serum creatinine level in the TDF and ETV groups at baseline, 6 mo, 12 mo and 24 mo.

RESULTS

Nine NRSs comprising 2263 participants met the inclusion criteria. Changes in creatinine levels were higher in the TDF group than in the ETV group at 6 mo [mean difference (MD) = 0.03 mg/dL; 95%CI: 0.02-0.04; I² = 0%], 12 mo (MD = 0.05 mg/dL; 95%CI: 0.02-0.08; I² = 78%), and 24 mo (MD = 0.07 mg/dL; 95%CI: 0.01-0.13; I² = 93%). The change in estimated glomerular filtration rate (eGFR) was significantly higher in the TDF group than in the ETV group at 6 mo [standardized mean difference (SMD), -0.22; 95%Cl: -0.36--0.08; I² = 0%], 12 mo (SMD = -0.24; 95%Cl: -0.43--0.05; I² = 50%), and 24 mo (-0.35; 95%Cl: -0.61- -0.09; I² = 67%).

CONCLUSION

TDF statistically significantly increased serum creatinine levels and decreased the eGFR in 6-24 mo compared to ETV, with moderate to low quality of evidence. However, the differences are negligible.

Nephrotoxicity: Role and significance of renal biomarkers in the early detection of acute renal injury

Nephrotoxicity is defining as rapid deterioration in the kidney function due to toxic effect of medications and chemicals. There are various forms, and some drugs may affect renal function in more than one way. Nephrotoxins are substances displaying nephrotoxicity. Different mechanisms lead to nephrotoxicity, including renal tubular toxicity, inflammation, glomerular damage, crystal nephropathy, and thrombotic microangiopathy. The traditional markers of nephrotoxicity and renal dysfunction are blood urea and serum creatinine which are regarded as low sensitive in the detection of early renal damage. Thus, the detection of the initial renal injures required new biomarkers which are more sensitive and highly specific that gives an insight into the site of underlying renal damage. Kidney injury molecule-1, Cystatin C, and neutrophil gelatinase-associated lipocalin sera levels are more sensitive than blood urea and serum creatinine in the detection of acute kidney injury during nephrotoxicity.

Renal safety of tenofovir and/or entecavir in patients with chronic HBV monoinfection

Background

Tenofovir disoproxil fumarate (TDF) and entecavir (ETV) are recommended as the first-line therapy for chronic hepatitis B (CHB) due to their genetic barrier to resistance and effectiveness of virological suppression. TDF and ETV may cause renal toxicity through various mechanisms such as renal tubular injury, apoptosis, and mitochondrial toxicity. The aims of the current review were to assess the potential renal toxicity associated with the use of TDF and ETV in patients infected with chronic hepatitis B virus (HBV) and to provide clinical perspectives on these two agents in the treatment of CHB.

Methods

A literature search of clinical studies published in PubMed and posted on ClinicalTrials.gov website was implemented to find studies evaluating the potential renal toxicity of TDF and ETV.

Results

Twenty-one studies were examined in this review. The TDF dose used in the studies was 245 or 300 mg/day and that of ETV was 0.5 or 1 mg/day. Based on the markers of renal function, patients treated with TDF were not more likely to show changes in renal function than those treated with ETV; however, the estimated glomerular filtration rates (eGFRs) of patients receiving TDF tended to be more clearly reduced than those of patients receiving ETV. The eGFRs of patients treated with TDF decreased in a time-dependent manner, whereas those of patients treated with ETV increased or decreased across various time points.

Conclusion

The data shown in this study suggest that use of TDF and ETV could be at least associated with reductions in renal function in patients with chronic HBV infection. However, various risk factors, such as pre-existing renal failure and comorbidities, are also associated with decreased renal function during the treatment of TDF and ETV. Thus, studies of management strategies for HBV-infected patients with these risk factors are necessary in the near future.