Relationship of Serum Cystatin C with C-Reactive Protein and Apolipoprotein A1 in Patients on Hemodialysis

HAART induced inflammation, toxicity and its determinants among HIV positive children in Addis Ababa, Ethiopia

Background

Highly Active Antiretroviral therapy (HAART) plays significant role in reduction of mortality among children infected with HIV. Despite the inevitable impact of HAART on inflammation and toxicity, there is limited evidence on its impact among children in Ethiopia. Moreover, evidence on contributing factors to toxicity has been poorly described. Hence, we evaluated HAART induced inflammation and toxicity among children taking HAART in Ethiopia.

Method

This cross-sectional study was conducted among children (<15 years old) taking HAART in Ethiopia. Stored plasma samples and secondary data from a previous study on HIV-1 treatment failure were used for this analysis. By 2018, a total of 554 children were recruited from randomly selected 43 health facilities in Ethiopia. The different levels of liver (SGPT), renal (Creatinine) and hematologic toxicity (Hemoglobin) toxicity were assessed using established cut-off value. Inflammatory biomarkers (CRP and vitamin-D) were also determined. Laboratory tests were done at the national clinical chemistry laboratory. Clinical and baseline laboratory data were retrieved from the participant's medical record. Questionnaire was also administered to study guardians to assess individual factors to inflammation and toxicity. Descriptive statistics was used to summarize the characteristics of the study participants. Multivariable analysis was conducted and considered significant at P < 0.05.

Result

Overall 363 (65.6%) and 199 (36%) of children taking HAART in Ethiopia developed some level of inflammation and vitamin-D in-sufficiency, respectively. A quarter of the children 140 (25.3%) were at Grade-4 liver toxicity while renal toxicity were 16 (2.9%). A third 275 (29.6%) of the children also developed anemia. Children who were on TDF+3 TC + EFV, those who were not virally suppressed and children with liver toxicity were at 17.84 (95%CI = 16.98, 18.82), 2.2 (95%CI = 1.67, 2.88) and 1.20 (95%CI = 1.14, 1.93) times risk of inflammation, respectively. Children on TDF+3 TC + EFV, those with CD4 count of <200 cells/mm³ and with renal toxicity were at 4.10 (95%CI = 1.64, 6.89), 2.16(95%CI = 1.31, 4.26) and 5.94 (95%CI = 1.18, 29.89) times risk of vitamin-D in-sufficiency, respectively. Predictors of liver toxicity were history of HAART substitution (AOR = 4.66; 95%CI = 1.84, 6.04) and being bedridden (AOR = 3.56; 95%CI = 2.01, 4.71). Children from HIV positive mother were at 4.07 (95%CI = 2.30, 6.09) times risk of renal toxicity while the different type of HAARTs had different level of risk for renal toxicity AZT+3 TC + EFV (AOR = 17.63; 95%CI = 18.25, 27.54); AZT+3 TC + NVP (AOR = 22.48; 95%CI = 13.93, 29.31); d4t+3 TC + EFV (AOR = 4.34; 95%CI = 2.51, 6.80) and d4t+3 TC + NVP (AOR = 18.91; 95%CI = 4.87, 27.74) compared to those who were on TDF+3 TC + NVP. Similarly, children who were on AZT+3 TC + EFV were at 4.92 (95%CI = 1.86, 12.70) times risk of anemia compared to those who were on TDF+ 3 TC + EFZ.

Conclusion

The high level of HAART induced inflammation and liver toxicity among children calls for the program to consider safer regimens for pediatric patients. Moreover, the high proportion of vitamin-D in-sufficiency requires program level supplement. The impact of TDF+3 TC + EFV on inflammation and vitamin-D deficiency calls for the program to revise this regimen.

The role of serum cystatin C in estimation of renal function in survivors of critical illness

PURPOSE

Estimating renal function by serum creatinine after critical illness is a challenging problem. However, the role of cystatin C for estimation of the renal function in survivors of critical illness is unknown. We aimed to compare the performance of serum cystatin C- and serum creatinine-based eGFR against a reference GFR using ^99mTc-diethylenetriaminepentaacetic acid (^99mTc-DTPA) in survivors of critical illness.

MATERIAL AND METHODS

Survivors of critical illness with stable hemodynamics and renal functions were recruited. Their serum creatinine and cystatin C levels were measured. eGFR were calculated by using various equations: 1)CKD-EPI SCysC; 2) Thai eGFR SCysC; 3)CKD-EPI SCr; 4)Thai eGFR SCr; 5)MDRD Caucasian SCr; 6)CKD-EPI SCr-SCysC. The ^99mTc-DTPA plasma clearance was used as a standard eGFR.

RESULTS

Forty-two patients were included. The bias (median percentage difference) between standard GFR and SCysC-based eGFR were 41.97% (95%CI 33.1% to 48.5%) for CKD-EPI SCysC and 31.72% (95%CI 21.1% to 34.9%) for Thai eGFR SCysC. While, the bias between standard GFR and SCr-based eGFR were -11.37 (95%CI -20.9 to 1.6) for CKD-EPI SCr, -18.30 (95%CI -26.3 to -10.6) for Thai eGFR SCr, and -27.17 (-43.7 to -19.1) for MDRD Caucasian SCr.

CONCLUSION

In survivors of critical illness, we demonstrated limitations of estimating GFR by both currently available SCysC and SCr-based equations. Therefore, further studies are still needed to develop better eGFR equations.

The influence of hemodialysis on FibroTest parameters

Chronic hepatitis C viral infection is an important cause of morbidity and mortality in patients with end-stage renal disease treated with hemodialysis. Liver fibrosis represents a main determinant of liver disease prognosis and clinical management, and its assessment by liver biopsy can decide treatment allocation. Although liver biopsy is the gold standard for staging liver fibrosis, it is an invasive procedure associated with complications that are more prevalent in patients with end-stage renal disease. FibroTest represents a surrogate marker of fibrosis which evaluates the levels of apolipoprotein A1, total bilirubin, haptoglobin, gamma-glutamyltransferase and α2-macroglobulin, generating a score that indicates the level of fibrosis. Discrepancies were observed in clinical practice between FibroTest score and histopathological findings. The aim of this study was to evaluate how hemodialysis influences the level of each FibroTest parameter and the final score. The systematic literature review conducted by us suggests that hemodialysis induces a reduction in apolipoprotein A1, haptoglobin and bilirubin levels, with an increase in gamma-glutamyltransferase and alpha-2-macroglobulin levels. In conclusion, hemodialysis modifies the levels of FibroTest parameters, suggesting that it may also have an impact on the accuracy of liver fibrosis assessment in hemodialysis patients.

How should procalcitonin and C-reactive protein levels be interpreted in haemodialysis patients?

BACKGROUND

Procalcitonin (PCT) and C-reactive protein (CRP) are used most widely in the diagnosis/treatment of bacterial infections. These are not infection-specific and may also show increases in other inflammation-causing cases.

AIM

To establish a new cut-off value for PCT and CRP to eliminate confusion in the diagnosis and treatment of bacterial infections in haemodialysis (HD) patients.

METHODS

A total of 1110 patients, 802 with undocumented infection and 308 with documented infection, was included in the study.

RESULTS

A total of 802 patients with undocumented infection had a mean CRP value of 12.2 ± 9.6 mg/dL and a mean PCT value of 0.51 ± 0.96 ng/mL and the 308 patients with documented infection had a mean CRP value of 125.9 ± 83.3 mg/dL and a mean PCT value of 13.9 ± 26.9 ng/mL at the time of admittance. In HD patients, the cut-off values for CRP was determined as 19.15 mg/dL and for PCT as 0.685 ng/mL in the presence of infection. The use of these two parameters in combination (CRP ≥19.15 mg/dL and PCT ≥ 0.685 ng/mL) was found to have 95% positive predictive value (PPV) and 93% negative predictive value (NPV) for the diagnosis of infectious diseases in HD patients. When CRP ≥100 mg/dL and PCT ≥5 ng/mL, this was found to have 100% PPV and 94% NPV for the diagnosis of sepsis in HD patients.

CONCLUSION

We specified PCT and CRP cut-off values with high PPV and NPV for revealing the presence of bacterial infection and sepsis in HD patients.

Plasma cystatin-C and risk of developing gestational diabetes mellitus

AIMS

Cystatin-C, a low molecular weight protein, is effectively applied to evaluate the risk of developing renal insufficiency, cardiovascular disorders, neural defects, and inflammatory states. However, the role of this biomarker to monitor different pregnancy-related complications remains controversial.

MATERIALS AND METHODS

In the present study, we compared serum cystatin-C concentration between pregnant women with gestational diabetes mellitus (GDM) and healthy pregnant women to assess value of this biomarker to predict presence of GDM in these women. The study consisted of 60 consecutive pregnant women (30 women suffered GDM and 30 healthy pregnant women) enrolled in Afzalipour hospital in Kerman, Iran in 2012. Fasting blood sample was collected to perform measurements on plasma glucose, lipids, serum creatinine, and C-cystatin. Serum cystatin-C level was quantified using ELISA techniques.

RESULTS

Unadjusted comparison of cystatin-C level between the two study group showed no significant discrepancy between them so that the level of this biomarker in GDM group was 593.00±204.81 mg/L and in healthy group was 531.67±87.52 mg/L (P=0.137); while in multivariable linear model with the presence of associated variables, GDM was a main determinant for increased level of cystatin-C (standardized beta of 0.355, P-value of 0.014).

CONCLUSION

Gestational age was also identified to be another indicator of elevated cystatin-C. In final, our study showed that cystatin-C can be a reliable, useful and promising marker of GDM appearance in pregnant women.

Serum cystatin C as a predictor for cardiovascular events in end-stage renal disease patients at the initiation of dialysis

BACKGROUND

There has been no study to investigate whether cystatin C could predict cardiovascular events in incident dialysis patients. We aimed to delineate the role of serum cystatin C and cystatin C-based estimated glomerular filtration rate (eGFR(cysC)) for prediction of cardiovascular events.

METHODS

This study included 66 end-stage renal disease patients who survived for >3 months after the start of dialysis, and serum cystain C levels were measured at the point of dialysis initiation.

RESULTS

Serum cystatin C was correlated with blood urea nitrogen (r = 0.537, p < 0.001), serum creatinine (r = 0.480, p < 0.001) and smoking (r = 0.284, p = 0.021). Cystatin C was inversely correlated with age (r = -0.316, p = 0.01) and eGFR(Cr) by modification of diet in renal disease (r = -0.533, p < 0.001). Kaplan-Meier analysis for cardiovascular events revealed that patients in the group with lower cystatin C levels (<4.14 mg/L) had a better event-free survival rate than patients in the group with higher cystatin C levels (≥4.14 mg/L) (p = 0.039). In univariate analysis, cystatin C (hazard ratio (HR) 2.62, p = 0.011) and eGFR(cysC) (HR 0.64, p = 0.004) were significant factors for the prediction of cardiovascular events. After multivariate adjustment, serum cystatin C and eGFR(cysC) were independent determinants of cardiovascular events (HR 3.952, p = 0.001 and HR 0.640, p = 0.004, respectively).

CONCLUSION

Serum cystatin C might be an independent marker of cardiovascular events in incident dialysis patients. Furthermore, eGFR(cysC) based on measured serum cystatin C could have a new role in predicting cardiovascular events beyond the estimation of true GFR.

Evaluation of cystatin C with iohexol clearance in cardiac surgery

BACKGROUND

Post-operative renal dysfunction after cardiac surgery is not uncommon and can lead to adverse outcome. The ability to accurately monitor renal function is therefore important. Cystatin C is known to be a sensitive marker of the glomerular filtration rate (GFR), but it has not been fully evaluated in cardiac surgery. Iohexol clearance is considered a reliable reference method for the determination of GFR. The aim of this study is to, for the first time, evaluate the diagnostic accuracy of plasma cystatin C compared with iohexol clearance in cardiac surgery.

METHODS

Twenty-one patients scheduled for elective coronary artery bypass grafting were prospectively enrolled in the study. Before surgery and on the second post-operative day, an iohexol clearance was performed. Plasma cystatin C, plasma creatinine and plasma C-reactive protein were determined before surgery and on the first, second, third and fifth post-operative day. Estimated creatinine and cystatin C clearances were determined.

RESULTS

Post-operative cystatin C and 1/cystatin C correlated strongly to iohexol clearance (r=-0.90 and 0.86) and so did creatinine and 1/creatinine (r=-0.83 and 0.78). Estimated creatinine clearance differed from iohexol clearance (P<0.01), whereas estimated cystatin C clearance did not differ from iohexol clearance (P=0.81). No correlation was found between C-reactive protein and cystatin C.

CONCLUSION

This study indicates that clearance estimations based on cystatin C are more accurate compared with estimations based on creatinine in determining GFR in cardiac surgery. Cystatin C has, in this study population, a stronger correlation to iohexol clearance than creatinine.

Cystatin C as a Marker of Renal Function is Affected by HIV Replication Leading to an Underestimation of Kidney Function in HIV Patients

Background

Broad use of tenofovir and an ageing HIV-infected population have created an interest in renal function in HIV patients. Serum cystatin C is a newer marker of renal function and might be more sensitive than creatinine.

Methods

Patients were enrolled consecutively in an observational study. HIV-seropositive patients naive to antiretroviral therapy ( n=261) were compared with healthy volunteers undergoing check-up procedures ( n=193). Estimated glomerular filtration rate (eGFR) was derived using creatinine-based Modification of Diet in Renal Disease (MDRD) and Cockcroft–Gault formulas or cystatin C-based calculations. HIV-seropositive patients starting antiretroviral therapy ( n=92) were followed prospectively after enrolment.

Results

MDRD showed a higher median eGFR in antiretroviral- naive HIV-seropositive patients compared with controls (104 versus 93 ml/min; P<0.001). Cockcroft–Gault gave similar results (118 versus 106 ml/min; P<0.001). By contrast, cystatin C levels in HIV-seropositive individuals were higher, resulting in a lower median eGFR compared with controls (99 versus 120 ml/min; P<0.001). Cystatin C was positively correlated with HIV RNA ( r=0.33, P<0.01) and inversely correlated with CD4+ T-cell count ( r=-0.29, P<0.01). Initiating antiretroviral therapy ( n=92) decreased cystatin C levels and led to an increased cystatin C-based eGFR from median 84 to 103 ml/min at week 24 ( P<0.001). Serum creatinine was not substantially altered.

Conclusions

Correlation of cystatin C with HIV RNA and CD4+ T–cell count, plus decrease of cystatin C after suppression of HIV replication, suggest an increase of cystatin C levels by active HIV infection. This might result in overestimation of renal impairment, particularly in treatment-naive patients. Therefore, use of cystatin C to calculate GFR in HIV-seropositive individuals should not be recommended without further validation.