Data-entropy analysis of renal transplantation data.

INTRODUCTION: The terms entropy and robustness are currently used by biomedical investigators to predict the risk of change in a system. The former is the mathematical identification of uncertainty about a system, while the latter is the likelihood of system stability. We conducted an entropy-based analysis of our renal transplantation data set. MATERIALS AND METHODS: The input variables in our model included donors and recipients, past medical history, and other clinical data. The output variables were 6- month, 1-year, and 2- year patient and graft survivals. Data-entropy analysis was performed with Ontonix s.r.l. software (www.ontonix.com). RESULTS: The total input and output entropy was 13.14 and 1.54, respectively. The mean input and output robustness was 39.14% and 29.54%. The robustness amplification index was 0.75. The minimum entropy of the input variables was reported for a history of myocardial infarction (0.07), vascular disease (0.1), bladder residual (0.13), or urologic surgery (0.15). The minimum entropy of the output variables was 0.20 for 6-month patient survival; 0.22 for 1-year patient survival; 0.25 for 6-month graft survival; 0.27 for 1-year graft survival; 0.28 for 2-year patient survival; and 0.32 for 2-year graft survival. CONCLUSION: Data-entropy analysis demonstrated a high stability of our transplantation data set. Nevertheless, long-term outcomes, especially those of graft survival, were slightly more unpredictable.

Diabetes as the cause of end-stage renal disease affects the pattern of post kidney transplant rehospitalizations.

INTRODUCTION: Although there are reports that link diabetes-induced end-stage renal disease (ESRD) with several post renal transplantation complications and conditions, few studies have directly focused on this issue. This study compared the pattern of rehospitalizations after renal transplantation among diabetic versus nondiabetic ESRD patients, measuring causes, length of stay, outcomes and costs. METHODS: We retrospectively reviewed 366 randomly selected rehospitalization records of kidney transplant recipients between 1994 and 2006, including 69 who underwent renal transplantation due to diabetic nephropathy and 297, due to nondiabetic ESRD. We compared the two groups with respect to demographic and clinical variables: donor source, readmission pattern, rehospitalization cause, time interval between transplantation and hospitalization (T-H time), length of hospital stay (LOS), and intensive care unit (ICU) admission, hospital charges, and inpatient outcomes of graft loss and mortality. RESULTS: The diabetes group, compared with nondiabetic group, had a greater mean age (53 +/- SD vs. 39 +/- SD years), proportion of admissions due to infections (44.9% vs. 32%) or renal dysfunction (14.5% vs. 29.6%), mean hospital charges ($5056 vs. $3046), and hospital mortality (18% vs. 4.3%; P<.05). Diabetic patients were readmitted sooner after transplantation than nondiabetic patients (11 vs. 18 months; P<.05). There was no difference between the groups with regard to gender, donor source, LOS, ICU admission, and graft loss. CONCLUSION: The etiology of ESRD should be considered for scheduling post renal transplantation follow-up. Renal transplant recipients with diabetes-induced ESRD need further attention in follow-up programs.

Prediction of inpatient survival and graft loss in rehospitalized kidney recipients.

INTRODUCTION: Despite a sizeable amount of research conducted hitherto into predictors of renal transplantation outcomes, there are scarce, data on predictors of in-hospital outcomes of post-kidney transplant rehospitalization. This study sought to provide a user-friendly prediction model for inpatient mortality and graft loss among rehospitalized kidney recipients. METHOD: This retrospective review of 424 consecutive kidney recipients rehospitalized after kidney transplantation between the years 2000 and 2005 used multiple logistic regression analysis to evaluate predictors of hospitalization outcomes. RESULTS: Multivariate analysis showed that age at admission, diabetes mellitus as the cause of end-stage renal disease (ESRD), admission due to cerebrovascular accident (CVA), surgical complications were predictors of in-hospital death; age at transplantation, surgical complications, and rejection were predictors of graft loss. Equation for prediction of in-hospital death was Logit(death) -0.304 * age at transplantation (year) + 0.284 age at admission (year) + 1.621 admission for surgical complication + 4.001 admission for CVA-ischemic heart disease + 2.312 diabetes as cause of ESRD. Equation for prediction of in-hospital death was Logit(graft loss) = 0.041 age at transplantation (year) + 1.184 admission for graft rejection + 1.798 admission for surgical complication. CONCLUSIONS: Our prediction equations, using simple demographic and clinical variables, estimated the probability of inpatient mortality and graft loss among re-hospitalized kidney recipients.

Hospitalization databases: a tool for transplantation monitoring.

INTRODUCTION: We sought to account for changes in posttransplant hospitalization patterns in terms of the changes in demographic and transplantation-related variables. METHODS AND MATERIALS: We retrospectively analyzed 1860 cases of kidney transplantation performed between 1992 and 2004 in terms of demographic and transplantation-related variables. Of the 1860 cases, rehospitalization records in the first year posttransplantation were available for 1152 cases, which were assessed for causes of admission, mortality, graft loss, length of stay, and hospital charges. RESULTS: The pattern of rehospitalizations showed the following trends: (1) Increased rate of infection; (2) Decreased rate of graft rejection; and (3) Peak costs of rehospitalization between 1999 and 2000. CONCLUSION: We believed that the increased infection rate and decreased rejection rate may have been related at least partly to the shift in the treatment protocol from azathioprine-based to mycophenolate mofetil regimens in 2000. Furthermore, the peak in the relative frequency of diabetes mellitus and hypertension as the etiology of end-stage renal disease among those having undergone transplantation between 1999 and 2000 may have been responsible for the peak in rehospitalization costs and length of hospital stay. We are strongly of the opinion that hospital statistics are a valuable tool for health care policymakers to monitor transplantation outcomes.

The outcome of diverticulosis in kidney recipients with polycystic kidney disease.

INTRODUCTION: Diverticulosis is a common finding in autosomal-dominant polycystic kidney disease (ADPKD). To avoid the serious complications of diverticulosis after kidney transplantation, some policies have recommended aggressive actions, such as elective colectomy. These policies are not widely agreed upon. This controversy led us to investigate the serious complications and the outcome of diverticulosis in ADPKD kidney recipients to see whether such therapies are justified. MATERIALS AND METHODS: From 2002 to 2006, we followed 18 ADPKD kidney recipient patients with barium enema-documented diverticulosis. All subjects were asymptomatic for diverticulosis at the time of transplantation. The mean value +/- SD of follow-up duration was 25.4 +/- 28.5 months. We documented demographic data, familial history of ADPKD, barium enema findings, and complications as well as graft and patient survivals. RESULTS: Hepatic flexure was the most prevalent site for diverticula. The mean (SD) of diverticular count was 6 +/- 5.1. Patients with a familial history of ADPKD showed a higher number of diverticular (P=.01). Diverticulitis occurred in three patients, all of whom died. CONCLUSION: Diverticulitis is a fatal and not rare complication in ADPKD patients. The rate of complications in our study was similar to previous findings, but we observed serious complications even among patients asymptomatic at the time of transplantation. The decision to take aggressive action such as elective colectomy is still a matter of debate that needs further evaluation.

Are all domains of quality of life poor among elderly kidney recipients?

BACKGROUND: This study sought to answer whether all domains of HRQoL are low among elderly kidney recipients. METHODS: A cross-sectional study of 162 renal transplanted subjects included group I (age<40 years, n=85), group II (age between 40 and 55 years, n=55), and group III (age >55 years, n=22). We compared the total score of the Short Form health survey (SF-36) and its eight subscales, including physical functioning (PF), social functioning (SF), role limitations due to physical health problems (RPh), role limitations due to emotional problems (REm), mental health (MH), vitality (VT), bodily pain (BP), and general health perceptions (GH) between the study groups. RESULTS: As compared to groups II and I, group III, showed significantly lower scores of REm (49.12 +/- 23.22, 63.03 +/- 26.33, 64.36 +/- 26.54, P=.08), PF (48.94 +/- 27.41, 72.69 +/- 25.54, 72.14 +/- 22.79, P=.001) and SF-36 total score (46.79 +/- 10.52, 54.77 +/- 10.66, 54.09 +/- 9.35, P=.01). There were no significant differences among SF, RPh, MH, VT, and BP. Group III reported better GH than groups II and I (52.36 +/- 9.18, 48.71 +/- 12.01, 43.50 +/- 14.81, P=.020). CONCLUSIONS: Increasing age did not result in poor health-related quality of life in all domains. The general health perception was better in the elderly, which might be due to their better coping ability.

Outcome of living kidney transplant: pediatric in comparison to adults.

BACKGROUND: Renal transplantation is the most optimal way to manage children with end-stage renal disease. Despite its benefits, pediatric renal transplantation is a challenge for several transplantation centers in terms of achieving a satisfactory outcome. We sought to compare the long-term outcome of pediatric versus adult recipients who underwent renal transplantation. METHOD: We examined, 2631 recipients of a first kidney from a living donor between 1982 and 2002. The two groups were matched for immunosuppressive therapy and number of HLA mismatches. The patients were divided into a pediatric (n=301; age 18 years) to compare 5-year patient and graft survivals. RESULTS: The mean ages of the pediatric and adult groups were 40 +/- 13 and 14 +/- 13 years, respectively. The 5-year graft survival was lower among the pediatric versus the adult group (56% vs 68%; P=.015) with no difference in patient survival (88% vs 86%; P>.05). CONCLUSION: The poorer graft survival in pediatric transplantation may be due to the nature of pediatric transplantation, in terms of inconsistent adherence to medication regimens, worse side effects of medications, higher rate of graft rejection due to recurrent disease, and more intense immunoreactivity of children.

Severity of chronic pain affects health care utilization after kidney transplantation.

BACKGROUND: While the association between chronic pain and high health care utilization is a known issue in the general population, this relation has not been well studied among kidney transplantation patients. METHODS: The subjects were first-time kidney transplant recipients engrafted between 2003 and 2006 and 6 months to 5 years postoperatively. Using SF-36 Bodily Pain Scale, patients were categorized in three groups: group I, those with scores over 66.6; group II, between 66.6 and 33.3; and group III, over 33.3. The subjects' health care utilization was prospectively assessed by recording the number of hospital admission days and the frequency of home nurse visits, outpatient physician visits, and emergency department visits for any medical reason in a 6-month period. RESULTS: A stepwise increase in the frequency of patients admitted to the hospital (P=.017), and those referred to emergency departments (P=.007) was correlated with greater severity of pain in the three groups. However, the frequency of patients having outpatient physician visits (P=.30) or home nurse visits (P=.387) did not vary significantly. Similarly, with increased pain severity, an increase was observed in the number of emergency department visits (P=.005) and duration of hospital stays (P=.049), but not in the number of home nurse (P=.890) or physician visits (P=.112). CONCLUSION: The severity of pain seems to increase the amount of health care use among kidney transplant patients. To minimize associated costs, appropriate pain rehabilitation programs are suggested.

Changing treatment protocol from azathioprine to mycophenolate mofetil: decrease in renal dysfunction, increase in infections.

INTRODUCTION: Immunosuppression for renal transplantation has shifted from azathioprine (AZA) regimens to those containing mycophenolate mofetil (MMF). This study investigated the impact of this change on the causes for rehospitalization as well as on graft and patient survival. METHODS: In this retrospective cohort study, we reviewed long-term patient and graft survivals as well as the causes of posttransplant admissions for 893 kidney recipients. Data on survival and readmissions were available for 811 subjects, who were divided to into the AZA cohort (n=289, transplantation between 1998 and 1999) and the MMF cohort (n=567, transplantation between 2000 and 2001). Survival, the cause for readmission, time interval between transplantation and readmission, intensive care unit (ICU) admission, mortality, and graft loss were compared between the two cohorts. RESULTS: Five-year patient and graft survival rates were 85% and 67% for the AZA cohort and 91% and 68% for the MMF cohort (P=.013). There were 202 (71%) and 371 (72%) readmissions registered for the AZA and MMF groups, respectively. In comparison with the AZA cohort, while readmissions secondary to graft rejection showed a significant decrease in the MMF cohort (62% vs 35%, P=.000), readmissions secondary to infections exhibited a significant increase (37% vs 50%, P=.002). A marginally significant increased mortality rate (2% vs 5%, P=.087) and ICU admission rate (3% vs 6%, P=.062) were also observed in the MMF cohort by comparison with the AZA cohort. CONCLUSION: The shift in the immunosuppression protocol from AZA to MMF, albeit advantageous in many instances, can sometimes undermine the outcome by giving rise to such complications as high infection rates.