Posttransplantation glomerulonephritis: risk factors associated with kidney allograft loss

AIM OF THE STUDY

Chronic glomerulonephritis (GN) is reported as a common cause of late kidney allograft loss. The aim of this study was to identify risk factors associated with kidney allograft loss in the course of posttransplantation GN.

PATIENTS AND METHODS

The study analyzed 75 kidney allograft recipients with biopsy-confirmed posttransplantation GN, including 27 cases of immunoglobulin (Ig)A nephropathy (IgAN), 30 of membranous GN (MGN), 6 of mesangiocapillary GN (MCGN); and 12 of focal segmental GN (FSGS). The risk factors for kidney allograft loss, defined as dialysis reintroduction after GN onset, were identified through are historical cohort study.

CLINICAL FINDINGS

After the onset of posttransplantation GN, the median time to dialysis introduction was 46 months. The risk factors for kidney allograft loss were as follows: male gender (hazard ratio [HR] = 1.92; 95% confidence intervall [CI] 1.0-3.70; P = .052), initial unsatisfactory kidney function (HR = 1.86 per 1 mg/dL serum creatinine increment; 95% CI 1.0-3.46; P < .05), graft dysfunction at diagnosis (HR = 1.65 per 1 mg/dL serum creatinine increment; 95% CI 1.32-2.07; P < .001), nephrotic syndrome (HR = 2.3; 95% CI 1.13-4.99; P < .05) late-onset GN (HR = 1.1 per each additional year of observation, 95% CI 1.0-1.21; P < .05), and MPGN as a type of GN. Enhanced immunosuppression increased and ACEI and/or statin treatment decreased the risk of return to dialysis, respectively: HR = 1.56, 95% CI 0.76-3.18, P = .22; HR = 0.39, 95% CI 0.16-0.98, P = .0037; and HR = 0.367, 95% CI 0.15-0.88, P = .025.

CONCLUSIONS

Identification of risk factors can help discover patients who will have a faster progression to kidney allograft loss due to GN. In posttransplantation GN, statins and/or ACEI should be prescribed, if there are no contraindications.

Detection of Clostridium difficile in stool samples from patients in the early period after liver transplantation

OBJECTIVE

We examined the frequency of detection of Clostridium difficile (CD) toxins compared with the recovery of C. difficile in stool specimen cultures among orthotopic liver transplant (OLT) patients with nosocomial diarrhea in the early period.

MATERIALS AND METHODS

The study included stool samples obtained during the first 30 days after OLT in adults who were suspected of CD-associated diseases. The identification of cultured CD strains was performed by standard microbiological methods. The presence of CD toxins was assayed using a commercial immunoassay.

RESULTS

All patients were followed prospectively for CD infections from the date of OLT for the first 4 weeks after surgery. Among 54 samples, 16.7% were culture-positive for CD. CD toxins were tested on 54 samples, yielding 63% toxin-positive samples and 30% toxin- and culture-negative results. In the first week after OLT, samples from 19 patients were subjected to CD investigation. Among 19 samples positive for toxin, 52.6% of all samples were culture-negative. We analyzed 35 samples from the second to the fourth week after OLT in 31 recipients. Among 35 samples, 68.6% and 25.7% were positive for CD toxin and for culture, while 20% of samples were negative for toxin and culture.

CONCLUSION

In our study, 63% of samples were toxin-positive with 16.7% yielding growth of CD and 30% being negative for toxins and cultures.

Serratia marcescens isolated in 2005 from clinical specimens from patients with diminished immunity

Serratia marcescens is an important agent in hospital infections. The aim of this paper was to compare the resistance patterns of S. marcescens strains isolated during 1 year from patients of various wards of the Institute of Transplantology. The mechanisms of beta-lactam antibiotic resistance were of especial interest. We investigated the 81 strains of S. marcescens, isolated during 2005 from patients on 3 wards and 1 clinic of the Transplantation Institute. An unusually high resistance to most antibiotics was observed among S. marcescens strains. Extended spectrum beta-lactamases (ESBLs) were probably produced by 63.2% to 84.6% of strains, depending on the ward. Additionally, about 30% of them were probably derepressed AmpC producers. The patterns of resistance indicated that at least 2 resistant clones of S. marcescens spread among the patients. One of the clones demonstrated both ESBL and derepressed AmpC production and was susceptible only to carbapenems. The second, producing ESBL, was susceptible to piperacillin/tazobactam and carbapenems. All investigated strains were resistant to nitrofurantoin. Strains of the second group were rarely susceptible to other antibiotics: aminoglycosides, ciprofloxacin, cotrimoxazole, or fosfomycin.

Surgical site infections in liver recipients in the early posttransplantation period: etiological agents and susceptibility profiles

OBJECTIVE

This study evaluated the frequency of microbial isolates and their susceptibility profiles from cultures at the surgical site of 83 liver recipients in the early posttransplantation period.

PATIENTS AND METHODS

We prospectively collected microbiologic culture data on 83 adult patients undergoing orthotopic liver transplantation (OLT) using standard procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was performed by the Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

All patients were followed prospectively for the first 4 weeks after surgery. Among 284 microbial isolates from clinical surgical site samples in 80 liver recipients, cultures were positive in 110 samples. The most commonly isolated species were: Gram-positive cocci (n = 222 isolates, 78%) with dominance of methicillin-resistant coagulase-negative staphylococci (MRCNS; 42%) and high-level aminoglycoside-resistant enterococci (HLAR strains; 24.3%). Gram-negative bacteria were identified in 21.5% of positive cultures, including 30 strains (24%) from the Enterobacteriaceae family, with 13.3% of extended spectrum beta-lactamase producers [ESBL(+)]. Significant differences (P = .0012) were observed during the analysis of changes in the occurrence of Gram-positive bacteria isolated from the surgical site in the first week versus the second to the end of the fourth week.

CONCLUSION

Gram-positive bacteria predominated as 78% of isolates.

Mode of delivery in women after liver transplantation

AIM

A high rate of cesarean sections has been reported among high-risk pregnancies in liver transplant recipients. The aim of this study was to analyze the course of deliveries and the indications for cesarean sections in women after liver transplantation.

MATERIALS AND METHODS

From 2001 to 2006, we noted 21 deliveries in 17 liver recipients. The mean age of women was 27.9 +/- 6.6 years and the mean time from transplantation to pregnancy was 4.3 +/- 3.6 years. Most patients were primigravidas on tacrolimus-based immunosuppressive regimens. We retrospectively analyzed obstetric data regarding the delivery and the early puerperium.

RESULTS

We noted 6 vaginal deliveries (29%) and 15 cesarean sections (71%). Mean gestational age in the group of vaginal deliveries was 37.6 +/- 2.2 weeks. No labor complications were noted. All neonates were delivered in a good state (Apgar score from 8 to 10 points) with mean birth weight of 2725 g. All cesarean sections were performed for obstetric indications: fetal distress, breech presentation, intrauterine growth retardation, or complications related to premature labor. Mean gestational age was 37.0 +/- 1.9 weeks. The Apgar scores ranged from 4 to 10 points; mean birth weight was 2787 g. The mean period of hospitalization after surgical labor was 4 days longer compared with the vaginal delivery group.

CONCLUSION

The high rate of cesarean sections (71%) in liver recipients is associated with a great incidence of obstetric complications of pregnancy. Safe and uneventful vaginal delivery is possible with growing experience in the management of pregnant transplanted women.

Quality of life after liver transplantation--preliminary report

BACKGROUND

Liver transplantation (OLTx) is an optimal method of treatment of end-stage liver failure. It gives a chance to get back to an active life. 80-90% of patients survive over 1 year after liver transplantation with a perspective of a long life.Recently more attention is being paid to health related quality of life (QoL). It is considered as a combination of physical and mental condition, social and economical state and somatic experience. The aim of the study was to analyze patient's QoL after OLTx compared to the condition before OLTx.

MATERIAL/METHODS

123 patients 1-12 years after transplantation were included in the study. The study was conducted in Outpatients Clinic of Immunology, Transplantology and Internal Medicine Department and Transplantation Medicine and Nephrology Department of Warsaw Medical University between October 2007 and January 2008. Original questionnaire was used, consisting of 8 general questions and 44 detailed questions concerning pre- and posttransplant period. Information about physical condition (health, mobility, basic functions, drug side effects), mental condition (anxiety, happiness, cognition disorders), social function (family, friends, work) and economic status were gathered. "Never, sometimes, often, very often" score was used.

RESULTS

Majority of subjects de fi ned their quality of life and physical condition before transplantation as poor, and post transplantation - as good. The respondent's mental condition didn't differ much before and after transplantation. Level of satisfaction was higher after transplantation. Health condition in some cases affected patients' family life, however it often devastated their social life before OLTx. Most patients were on disability pension and after transplantation they indicated the influence of health on their financial condition.

CONCLUSIONS

The quality of life after liver transplantation gets better and it's de fi ned as good or very good. During the analysis of QoL a difference between conditions before and after LTX wasn't observed.

[The methods of therapy ESRD patients infected with the human immunodeficiency virus-HIV]

The human immunodeficiency virus (HIV) pandemic has spread to every country in the world and has infected about 60 million persons worldwide, including 20 million who have already died. In Poland are infected 11,181 people. Highly active antiretroviral therapy (HART) has significantly prolonged the survival of HIV-positive patient. HIV infection can cause end-stage renal disease (ESRD) through both HIV-associated nephropathy (HIVAN) and antiretroviral drug toxicity. Until recently, chronic dialysis (HD or PD) was the only form of treatment available for these patients. Kidney transplantation is an alternative method to dialysis and improve the quality of life in HIV-positive ESRD patients. In this article authors present the general information about HIV infection (epidemiology, diagnosis and treatment) as well as methods of therapy ESRD like hemodialysis (HD), peritoneal dialysis (PD) and kidney transplantation.

Safety and efficacy of high dose ATG bolus administration on rewascularization in kidney graft patients--long term results

BACKGROUND

Various preparations of ALG/ATG have been used in clinical transplantation for more than 30 years. In recent years the number of high immunological risk patients has increased and biological agents are being used as induction therapy. The aim of this prospective, randomized study was to asses the safety and efficacy of a single high dose of antithymocyte globulin (9 mg/kg ATG Fresenius S) in cadaveric renal transplantation. The maintenance immunosuppressive regimen consisted of steroids, mycophenolate mofetil (converted after the fourth month to azathioprine), and cyclosporine.

MATERIAL/METHODS

Between November 1997 and April 1999, 79 recipients were included into the study. Patients were randomized to ATG (n=40) or the standard treatment group (n=39) with a follow up period of 5 years.

RESULTS

The incidence of acute rejection was lower in the ATG group--9 patients (22.5%) compared to 14 in the control group (35.9%) (p=NS). The total number of all acute rejections episodes in the ATG group was 11 and 23 in the control group. Steroid resistant rejections occurred in 4 (10%) and 8 (20.5%) patients respectively. The number of infectious complications was similar in both groups (65% - ATG, 67.5% - control, p=NS). Graft survival was 70% for the ATG and 69.23% for the control group. Death censored graft survival was 85% in the ATG and 74.43% in the control group (p=NS).

CONCLUSIONS

Induction Therapy with high single dose of ATG seems to be safe and efficacious in kidney transplantation.

Hodgkin-like lymphoma, simulating anaplastic large cell lymphoma in the patient after renal transplantation--unusual case report and literature review

We report the atypical case of posttransplant lymphoproliferative disorder (PTLD) diagnosed in 55-year men 9 years after renal transplantation. It was evaluated only by bone marrow biopsy, which showed its total involvement with malignant lymphoma. It was composed of two populations of lymphoid cells: large RS-like cells and small to medium ones, with slightly angular nuclei without visible nucleoli. Both cellpopulations did not show positive reaction for typical B cell markers (CD20, CD79a). Large RS-like cells were positive with CD30 and EBV-LMP. However, negative reaction with CD15 and positive reactions with UCHL1 and EMA were not consistent with classical type of Hodgkin lymphoma. Morphological picture and immunophenotype had suggested anaplastic T cell lymphoma. Because of negative reaction with ALK1, initial diagnosis was ALCL ALK-negative. Then, additional stains with BOB1 and Oct2 were performed, which were positive. Taking it into account the diagnosis was changed; finally Hodgkin-like B lymphoma was diagnosed. The patient was treated with CHOP regimen with good response. 5 years after primary diagnose of PTLD he is steel free of disease.

CONCLUSIONS

1. Apart from typical forms of PTLD, one may expect cases with nonspecific morphological picture and phenotype. 2. Negative reactions with typical immunohistochemical markers for lymphocytes of B cell line do not exclude the possibility of B-cell proliferation.

Renin-Angiotensin-Aldosterone system inhibitors and statins prolong graft survival in post-transplant glomerulonephritis

BACKGROUND

Novel immunosuppressives neither prevent nor attenuate post-transplant glomerulonephritis, third common cause of late allograft loss. Data addressing influence of ACEI/ARA and statins on kidney transplants survival is contradictory. The aim of this study was to evaluate efficacy of therapeutic interventions undertaken in post-transplant glomerulonephritis.

MATERIAL/METHODS

In 75 individuals with biopsy-confirmed post-transplant glomerulonephritis, engrafted in Warsaw Transplantation Institute, graft survival from index biopsy to permanent dialysis need, in regard to numerous therapeutic interventions was analysed. Evaluation of graft survival was performed using Kaplan-Meier estimator, log-rank and Wilcoxon tests. Relations between introduced treatment and time to graft loss was expressed with hazard ratio (HR), results regarded significant at p<0.05.

RESULTS

Glomerulonephritis diagnosis was established 50.2+/-39.5 months after engraftment. Maintenance immunosuppression modifications included: methylprednisolone infusions (n=28), cyclofosfamide/ chlorambucil introduction (n=10), mycophenolate mofetil addition to maintenance treatment (n=23). Immunosuppression modifications did not result in graft survival prolongation. Statins (n=20) and renin-angiotensin-system blockers (n=49) substantially diminished the risk of graft loss (respectively: HR=0.37 (95% CI 0.15-0.88), p<0.02. and HR=0.39 (95% CI 0.16-0.98; p<0.05). The effect persisted after adjustment for presentation with nephrotic syndrome, graft dysfunction, mean arterial pressure, immunosuppression enhancement with mycophenoalte mofetil. Best result was obtained with combined RAASB and statin treatment (HR=0.24; 95% CI 0.69-0.09, p=0.008).

CONCLUSIONS

According to our data statins and renal renin-angiotensin system blockers prolong graft survival in patients with posttransplant glomerulonephritis. We feel that these relatively safe agents, bringing also other pro fi ts, should be routinely applied in patients with post transplant glomerulonephritis.

Machine perfusion preservation improves renal allograft survival

Machine perfusion (MP) has been used as the kidney preservation method in our center for over 10 years. The first, small (n = 74) prospective, single-blinded randomized study comparing MP and Cold Storage (CS) showed that the incidence of delayed graft function was higher after CS. There have been no reports in the literature on the effect of storage modality on long-term function of renal allografts. This paper presents an analysis of long-term results of renal transplantation in 415 patients operated on between 1994 and 1999. Of those, 227 kidneys were MP-stored prior to KTx. The control group consisted of 188 CS kidney transplants. Kidneys were not randomized to MP or to CS. Donor demographics, medical and biochemical data, cold ischemia time, HLA match and recipient data were collected. Standard triple-drug immunosuppression was administered to both groups. Mortality, graft survival and incidence of return to hemodialysis treatment were analyzed. Despite longer cold ischemia time and poorer donor hemodynamics in MP group, 5-year Kaplan-Meier graft survival was better in MP-stored than in CS-stored kidneys (68.2% vs. 54.2%, p = 0.02).

CONCLUSION

In this nonrandomized analysis, kidney storage by MP improved graft survival and reduced the number of patients who returned to dialysis.

Primary Kidney Allograft Dysfunction Due to Myeloma-Cast Nephropathy: A Case Report

Cast nephropathy is a rare event among renal transplants, usually associated with multiple myeloma or light chain nephropathy. Herein we have reported primary graft dysfunction early posttransplantation due to cast nephropathy, associated with thrombotic microangiopathy.

Insulin resistance in kidney allograft recipients treated with calcineurin inhibitors

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is one of the main complications observed in patients after organ transplantation. The incidence of PTDM in transplant recipients is about 9 times higher than in general population. The reported incidence of PTDM varied throughout the years due to different diagnostic criteria of diabetes mellitus. Nowadays the rate of PTDM amounts to 3-19%.

MATERIALS/METHODS

1270 patients after kidney transplantation, who remained under medical care in the outpatient service at the Transplantation Institute in Warsaw, were taken into consideration. The investigated group comprised 207 patients. 133 of them developed DM that constitutes the incidence of PTDM at 10.5%.

RESULTS

In the present study several risk factors that are important for PTDM development were observed: male gender, HLA A3, family history of DM, increased body weight (rather than BMI only), tacrolimus--based immunosuppressive regimen, early hyperglycemia. Patients with PTDM developed hypertension more frequently, had higher serum triglycerides levels in the period before the onset of diabetes. The rate of acute rejection episodes in this group was higher compared with the nondiabetic transplant controls. The PTDM group presented with worse graft function and higher levels of proteinuria in 1-year observation. Tacrolimus--based therapy led to higher peripheral insulin resistance and hyperinsulinemia in comparison to cyclosporine--based regimen.

CONCLUSIONS

The proper management of the above described risk factors and the right treatment of PTDM may considerably influence life expectancy rate and quality of life in transplanted patients.

Organ donation in Poland 2006

Organ transplantation program has been slowly developing over last 30 years. The number of DD (deceased donors) stabilized on the level of approximately 13/million of population. Multiorgan donation has been 45%, due to some problems with donor management. Polish Transplant Coordinating Center POLTRANSPLANT which is responsible for organization of procurement, organ allocation and providing several registries (registry of objections, registry of transplantation, waiting lists of potential organ recipients etc). National data on organ donation and transplantation are each year submitted to the Ministry of Health and the National Transplantation Council which is the Advisory Committee to the Minister.

Assessment of cadaveric livers discarded from transplantation. A correlation between clinical and histological parameters

BACKGROUND

We designed a study with the following aims: to assess tissue quality of 100 cadaveric livers discarded from transplantation, to identify discarded organs which could have been used either for transplantation or for isolation of hepatocytes, to assess donor clinical factors which may impact the histology.

MATERIAL/METHODS

Liver wedge biopsies were performed during kidney procurement, sent for processing and data interpretation.

RESULTS

In 46% of the evaluated tissues severe changes were found; these organs according to pathologists were "not suitable for transplantation". In 19% less pronounced changes classified organs as "probably not suitable for transplantation". In 35% biopsies only minimal changes were found; these organs were classified as "probably suitable for transplantation" and could have been harvested as marginal organs or at least used for hepatocytes isolation.

CONCLUSIONS

Results of biopsies suggested that approximately in one third of livers discarded from transplantation due to clinical donor parameters could have been harvested from histological point of view. Several donor clinical risk factors (alcohol addiction, hyperbilirubinemia, increased transaminase activity) correlate with severe histological changes rending the liver "not suitable for transplantation".

Early hyperglycemia after allogenic kidney transplantation

BACKGROUND

The aim of the study was to establish the impact of early hyperglycemia on development of diabetes mellitus (DM) in patients after kidney transplantation and to evaluate possible risk factors for post-transplantation DM. We also sought to assess the impact of early hyperglycemia and DM on the renal graft function in the long term (3 year follow-up).

MATERIAL/METHODS

1200 transplant patients from one center, were followed up for 3 years. The rate of chronic rejection, CMV infection, hypertension and dyslipidemia were analyzed. The renal allograft function was examined and pancreatic function peptide C concentration was determined.

RESULTS

Early hyperglycemia (within first week after transplantation) was detected in 76 out of 1131 patients (6.7%). In this group within three years observation posttransplantation diabetes mellitus (PTDM) was observed in 57 patients (relative risk 75%). In comparison, transplanted patients with good early glucose control had 8% risk of developing DM within the same period after transplantation. In addition early hyperglycemia predisposed to worse renal graft function and higher proteinuria. The incidence of hypertension as well as the rate of CMV infection was comparable in the DM group and in non-DM patients. PTDM patients had higher values of serum peptide C concentration (p < 0.05), additionally hyperinsulinemia was observed. The kidney allograft function assessed as serum creatinine level was significantly impaired after 3 years in PTDM group compared to non-DM patients.

CONCLUSIONS

Our date show the importance of normal glucose concentration in early period after transplantation as predictive factor for diabetes mellitus development and worsening of transplanted organs.

Combined oral contraception in women after renal transplantation

AIM

To assess safety of combined low-dose oral contraceptives in women after renal transplantation.

MATERIAL AND METHODS

Twenty six female renal graft-recipients, aged from 18 to 44 (mean 31 years), who used combined low-dose oral contraceptives after renal transplantation for at least 18 months were enrolled in the study. All patients had stable graft function with mean serum creatinine of 1.3 mg/dl. In 58% of women effective contraception was the mean indication for the therapy, in the remaining group pills were indicated additionally for the development of ovarian cysts and excessive menstrual bleedings. Ethinyl estradiol dose was 20 mug in 73% of cases and 30-35 microg in the remaining group.

RESULTS

No case of pregnancy was observed. Contraceptive therapy was discontinued in two cases: for profound vein thrombosis in one and deterioration of liver function in the other case. No side effects of contraceptives were observed in the remaining group of patients within at least 18-month observational period. No case of ovarian cyst was reported. Oral contraceptives were not found to influence body mass index (BMI), mean blood pressure, serum creatinine and biochemical parameters (AST, ALT, total bilirubin, glucose and cholesterol).

CONCLUSIONS

Despite the presence of relative contraindications for hormonal drugs (arterial hypertension and deteriorated liver function) in female renal recipients, administration of combined low-dose contraceptive pill should be taken into account as highly effective contraceptive method, that additionally regulates menstrual bleeding patterns, protects from ovarian cysts development and improves life quality of the patient.

Function of the ovaries in female kidney transplant recipients

OBJECTIVES

One of the effects of an improved general health state after successful kidney transplantation in women of reproductive age is recurrence of regular menstrual function.

MATERIALS AND METHODS

Sixty-three ovarian cycles in female kidney transplant recipient, aged from 18 to 44 years, at 1.5 to 15 years after transplantation, were compared with 50 cycles of healthy women. We monitored the menstrual cycle duration as well as follicle stimulation hormone (FSH), leutinizing hormone (LH), estradiol, progesterone, prolactin, creatinine, and testosterone serum concentrations as well as hematocrit and obtained sonographic observations of ovarian follicle growth and ovulation.

RESULTS

Of the recipients, 68.1% had regular menstrual cycles. Ovulatory cycles were observed in 45% of patients. Estradiol concentration established in the first phase of the cycle was significantly higher among the transplanted group (mean value 226.86 +/- 97.45 pg/mL vs 140.00 +/- 61.00 in the controls). A significantly lower level of progesterone (15.05 +/- 17.34 ng/mL vs 30.79 +/- 18.48 ng/mL in the controls) and of testosterone were observed in kidney recipients. Other hormonal parameters did not differ significantly between the groups.

CONCLUSIONS

Similar serum FSH, LH, and prolactin concentrations as well as increased levels of estrogens were observed in kidney transplant recipients compared with healthy nonrecipients. The rate of ovulatory cycles in regularly menstruated kidney graft recipients was similar to that of healthy women. Stabilization of graft function resulted in restoration of normal ovarian hormone metabolism and ovulatory cycles in female kidney transplanted recipients.

Influence of pancreas and kidney transplant function on recipient survival

The aim of this study was to evaluate long-term survival after simultaneous pancreas and kidney (SPK) transplantation in relation to function of both grafts. Among 67 recipients who received SPK transplants between 1988 and 2004, 35 had follow-up longer than 18 months, and were divided into: group I (n = 20), recipients with good function of both grafts; group II (n = 7), patients who had lost transplanted pancreas but had still good kidney graft function; group III (n = 8), patients who had lost both grafts. Comparison of survival rates and analysis of the reason of mortality among groups was performed. The cumulative survival rate was significantly higher in group I than in group III (after 3, 5, 10 years: 100%, 100%, 80% vs 75%, 50%, 37%, respectively). Cumulative survival rate for group II after 3, 5, 10 years was 100%, 100%, 33%, respectively. There were no significant differences in survival rates between groups I and II and between groups II and III. In group I deaths for cardiovascular event and for leukemia were noted. In group II deaths due to cardiovascular event and sepsis were observed. In group III all patients died due to cardiovascular events and the mean time from loss of pancreas and kidney graft function to death was: 75 +/- 51 months (range from 19 to 142), and 49 +/- 26 months (range 19 to 99), respectively. Good pancreas and kidney graft functions prevent death due to cardiovascular event.

The weight of pharmacokinetic parameters for mycophenolic acid in prediction of rejection outcome: the receiver operating characteristic curve analysis

Often the clinical researcher is confronted with the question of how accurate a particular laboratory test is to identify disease. To confirm the ability of pharmacokinetic (PK) parameters to discriminate between patients with or without acute rejection after kidney transplantation, an analysis of receiver operating characteristic (ROC) curves was performed in 51 adult patients, among whom nearly 50% experienced biopsy-proven acute rejection episodes during the first 90 days posttransplant. All patients received cyclosporine or tacrolimus, prednisone, and mycophenolate mofetil (MMF). The following PK variables were determined for mycophenolic acid, an active metabolite of MMF: predose (C(0)), maximum concentration (C(max)), and area under the concentration-time curve (AUC(0-12h)). ROC plots of sensitivity versus 1-specificity were generated to determine whether a particular PK parameter could discriminate renal transplant recipients with an acute rejection from those who experienced no rejection. Area under the ROC curves and the 95% confidence interval limits were calculated using the method of Hanley and McNeil. The C(0) and C(max) were less predictive values for acute rejection than AUC(0-12h). The AUC parameter appeared the most effective to discriminate an acute rejection episode during MMF therapy. This study indicated the utility of ROC curve analysis to select PK parameters to predict acute rejection episodes.