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.

Primary kidney disease and post-renal transplantation hospitalization costs.

BACKGROUND AND AIM: This study sought to assess posttransplantation hospitalizations costs in diabetic and nondiabetic subjects to see whether diabetes mellitus (DM) as a primary cause of end-stage renal disease (ESRD) increased posttransplantation hospitalization costs. METHODS: From 2000 to 2005, the hospitalization costs of 387 consecutive rehospitalizations of kidney recipients were retrospectively compared for two groups: patients with ESRD due to DM (n=71) and those with ESRD of non-DM etiologies (n=316). The hospitalization costs included the costs of hotel, medications, surgical procedures, paraclinical tests, imaging tests, health personnel time, special services (ie, patient transportation by ambulance), and miscellaneous costs. Societal perspective was used with costs expressed in PPP$ purchase power parity dollars (PPP$) estimated to be equal to 272 Iranian rials. RESULTS: Compared with the non-DM group, DM patients experienced significantly higher median costs both in total (1262 vs 870 PPP$, P=.001) and in cost components related to hotel (384 vs 215 PPP$, P=.001), health personnel time (235 vs 115 PPP$, P<.001), paraclinical tests (177 vs 149 PPP$, P=.012), and special services (100 vs 74 PPP$, P=.041). The mean of age was higher (P<.001), and the transplantation hospitalization time interval was also shorter in the DM group (median: 2.7 vs 12, P=.025). CONCLUSIONS: Considering DM as a leading cause of ESRD and its increasing prevalence in some countries, the association between hospitalization costs of posttransplant patients and DM may be of great economic importance to many transplantation centers.

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.

Medical comorbidities after renal transplantation.

BACKGROUND: Despite the amount of evidence regarding the negative impact of medical comorbidities after transplantation, little attention has been directly paid to the pattern of somatic comorbidities in renal transplant recipients. The aim of this study was to assess the prevalence of medical comorbidities after kidney transplantation. METHODS: In a cross-sectional study during 2006, we evaluated 119 kidney transplant recipients for somatic comorbidities by using the Ifudu comorbidity index, which evaluated the presence of 14 chronic illnesses among patients undergoing maintenance hemodialysis. Correlations of the Ifudu score with demographic and clinical data were also studied. RESULTS: Eighty-three (90.4%) subjects had at least one medical comorbidity. The mean comorbidity score was 5.17 +/- 4.50. The most frequent comorbidities were nonischemic heart diseases including hypertension (n=75; 63%), visual disturbances (n=42; 35.2%), low back pain and spine and joint disorders (n=30; 25.21%), and musculoskeletal disorders (n=28; 23.5%). A higher comorbidity score was significantly correlated with lower economic status (P<.05), but not with age, gender, marital status, educational level, cause, or duration of end-stage renal disease. CONCLUSION: The prevalence of medical comorbidities among kidney transplant recipients seems to be high, with the highest prevalence due to nonischemic heart diseases, visual disturbances, and musculoskeletal disorders. This highlighted the necessity of providing posttransplant care by a multidisciplinary team of specialists.

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.

Pain affects health-related quality of life in kidney transplant recipients.

BACKGROUND: Chronic pain is prevalent in end-stage renal disease patients undergoing chronic hemodialysis. We do not fully know the intensity of chronic pain experienced by kidney recipients in comparison to those on chronic hemodialysis and healthy controls. Moreover, the effect of chronic pain on kidney recipients' health-related quality of life (HRQoL) is yet to be comprehensively addressed. We designed this study to find an answer to these questions. METHODS: In this case control study, we studied 205 kidney recipients, 69 hemodialysis patients, and 100 healthy controls, who were matched for age, sex, monthly family income, and educational level. The patients were evaluated for the intensity of chronic pain by Visual Analogue Scale (VAS). HRQoL was measured with Short Form 36 (SF-36) in the kidney recipients. Chronic pain intensity was compared in the study groups, and in the kidney recipients the correlation between SF-36 subscores and severity of pain was assessed. RESULTS: Severity of pain in the kidney recipients was lower than the hemodialysis patients, but more than the healthy controls (P=.001). The VAS pain score negatively correlated with the scores of SF- 36 total (r=-.329, P=01), mental health (r=-.190, P=07), physical health (r=-.275, P=.001), physical function (r=-.339, P=.001), role limitation due to physical problems (r=-.478, P=.001), role limitation due to emotional problems (r=-.326, P=.001), and bodily pain (r=-.894, P=.001). DISCUSSION: The intensity of chronic pain experienced by the kidney recipients is less than that experienced by patients under chronic hemodialysis, but higher than healthy subjects. Focusing on chronic pain as a cause of post-renal transplantation morbidity is expected to improve post-renal transplantation quality of life.