The ability to predict the outcome in acute tubular necrosis (ATN) remains elusive despite considerable efforts. Accurate prediction is a crucial priority and has large economical and ethical implications, mainly to judge when treatment is futile and further efforts only prolong miserable agony. To analyze the influence of risk factors in the prognosis of ATN, we applied, in an initial phase, a prospective protocol of demographic data, cause of renal failure, diuresis, need of dialysis and clinical conditions in 228 patients using multiple linear and logistic regression models. In a control phase with 100 consecutive patients, we checked the accuracy of the results previously obtained, evaluating further the overall population of 328 patients in a synthetic phase. Finally, the validation of the equations obtained was verified in 25 patients from another hospital. As a complement of this 4-phase study, detailed statistical comparisons between both linear and logistic multiple regression models were undertaken. Correlation between probability of death obtained with equations from the initial phase applied to control patients and real evolution of these patients, survival or death, was excellent. The study of the synthetic phase revealed coma, assisted respiration, hypotension, oliguria and jaundice as having an independent positive influence on mortality and nephrotoxic etiology and normal consciousness on good prognosis. For the linear model, the same cut-off point of discriminant score (0.9) above which there were no chances for survival could be established in the 4 phases. With the logistic model, it only was found at later phases. The multiple linear was better than the logistic regression model in terms of better correlation with real mortality, better sensitivity and specificity intervals, easier use of discriminant cut-off point and better adjustment of distribution of standardized residuals to expected normal function. Early prognosis of ATN is possible and can be given using simple clinical features. A discriminant score allows to distinguish patients without chances for survival. The multiple linear is better than the logistic regression model in the prediction of the outcome in ATN.

A prospective study on hypotension in hemodialysis was performed in 60 nondiabetic patients at two different dialysate temperatures during 12 months. A 37 °C bath (3,723 sessions) was used and after the first 6 months the temperature was changed to 35 °C (4,019 sessions). The prevalence of symptomatic hypotension was 15.3% and it was closely correlated with the presence of other symptoms. The most affected populations were women, patients over 55 years of age, patients with low body surface area and patients with a cardiovascular disease. A slight but significant decrease of symptomatic hypotension was seen by using a 35 °C dialysate (16.4 vs. 14.3%, p < 0.01). In patients with frequent hypotension (in up to 30% of sessions), cool dialysate significantly reduced the incidence of the symptom (44.2 vs. 34.1 %, p < 0.001). These results were obtained in spite of a greater interdialysis weight gain at low temperature (2 ± 0.6 vs. 1.9 ± 0.7 kg, p < 0.001). We consider that low-temperature dialysis is a simple, useful and economic procedure, especially for highly symptomatic patients. The association of cooling dialysate with higher sodium concentration, bicarbonate and special membranes could reduce dialysis symptoms dramatically.

This study showed that DGF did not adversely affect kidney graft survival in patients without rejection. However, it increased the length of hospitalization and the number of graft biopsies, thus increasing the cost of transplantation. Moreover, rejection was more frequent in patients with DGF, and it had a negative impact on graft outcome. Because the association of DGF and rejection gave the poorest outcome, an effort should be made to prevent both complications.

Few studies have assessed the prevalence and outcome of acute renal failure (ARF) in the elderly. Among 437 ARF cases prospectively studied during a nine-year period in a nephrology department, 152 (35%) occurred in patients over 70 years of age (Group 1). Patients over 70 account for only 10.5% of all hospital admissions in our country, and prevalence of ARF was 3.5 times higher in these patients than in younger people. Acute tubular necrosis (ATN) was diagnosed in 40% of Group 1 and 52% of the younger patients (Group 2) (P less than .05), whereas prerenal ARF was found in 47% and 32%, respectively (P less than .001). Dehydration was the most frequent cause of prerenal ARF in the elderly (51%). The etiological distribution of ATN was similar in both groups, being of multifactorial origin in most cases. Oliguria was present in 49% of ATN in Group 1 and in 66% of Group 2 (P less than .05). There were no significant differences in dialysis needs. Mortality was higher in the elderly in all types of ARF, although differences did not reach statistical significance. Need for dialysis, mechanical respiration, decreased level of consciousness, and hypotension were associated with poor prognosis in both groups. Total recovery from ARF in older persons was less frequent and slower than in younger patients. It may be concluded that patients over 70 years of age are at high risk for developing ARF; nevertheless, age should not be used as a discriminating factor in therapeutic decisions concerning ARF.

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The prevalence of hyperuricemia was investigated in 214 kidney allograft recipients, 81 were on azathioprine and steroids and 133 on cyclosprine (CyA) and low-dose steroids or on triple therapy. All had stable renal function, serum creatinine < 2.5 mg/dl, and a follow-up between 12 and 120 months. At the time of the study, blood and urine samples were obtained to perform tests of renal function. The renal handling of urate was evaluated by a combined pyrazinamide and probenecid test in 35 selected patients (12 normouricemic on azathioprine, 9 normouricemic on CyA and 14 hyperuricemic on CyA). The prevalence of hyperuricemia was higher in the group of patients on CyA (19.7 vs. 66.9%, p < 0.001), as well as the concentration of serum urate (6.1 ± 1.9vs.7.6 ± 1.7, p < 0.001), and serum creatinine (1.2 ± 0.3 vs. 1.4 ± 0.4, p < 0.001). In patients on CyA, multivariate analysis showed that the most important predictive variables of hyperuricemia were: serum creatinine, FE_urate, diuretic use and CyA blood levels (r = 0.73, p < 0.0001). Thirteen patients on CyA (9.9%) had at least one episode of gouty arthritis. Those patients were older than the hyperuricemic patients without gout (45.7 ± 6.7 vs. 37.1 ± 13.5 years, p < 0.01), had worse renal function (serum creatinine 1.9 ± 0.4 vs. 1.5 ± 0.4 mg/dl, p < 0.01), and higher prevalence of hypertension (100 vs. 63.1%, p < 0.05). The combined pyrazinamide-probenecid test showed a lower FE_urate during the maximal probenecid-induced uricosuria (p < 0.05) and a lower urate secretion (p < 0.05) in hyperuricemic patients on CyA than in normouricemic on azathioprine or normouricemic on CyA. There were no differences either in the presecretory reabsorption or in the postsecretory reabsorption. According to the previous results, 20 hyperuricemic patients (11 with gouty arthritis) were treated with benziodarone (50-100 mg/day). At 1 month, there was a decrease in the serum urate (10.1 ± 1.8 vs. 5.1 ± 1.4 mg/dl, p < 0.01), and a parallel increase in FE_urate (7.1 ± 2.4 vs. 25.4 ± 7.4%, p < 0.001), that persisted after 1 year of follow-up. The drug was well tolerated, and we did not observe side effects. The serum creatinine, CyA dose and CyA blood levels remained unchanged. In conclusion, hyperuricemia is a frequent complication in transplant patients on treatment with CyA. Our data suggest that the disorder could be due to an impairment of the tubular secretion of urate. Benziodarone is an alternative to allopurinol for the treatment of this complication, which does not have important side effects.

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