When determining whether to offer a certain treatment, some physicians may consider a patient's age group rather than the individual patient. There is an assumption that many treatments are less likely to benefit patients of advanced age. Pascual and colleagues conducted a longitudinal study to determine if advancing age should be used as a discriminating factor in treating acute renal failure in patients 80 years of age or older.
Adult patients who were treated for acute renal failure at one of 13 hospitals during a nine-month period were included in the study. Demographic information, etiology of the acute renal failure, medications, serum creatinine levels, need for dialysis and mortality rates were recorded. Patients were included in the study if they had previously normal renal function and a rise of serum creatinine to more than 2.0 mg per dL (177 mmol per L) plus one of the following conditions: normal serum creatinine level at admission; elevated serum creatinine level at admission with at least 50 percent recovery by discharge; elevation of serum creatinine level at admission without evidence of chronic renal failure; or mild chronic renal failure (baseline serum creatinine level of greater than 3.0 mg per dL [265 mmol per L] with a sudden rise in serum creatinine).
The study population included 103 patients who were 80 years or older, 256 patients between 65 and 79 years of age, and 389 patients who were younger than 65 years. The most likely cause of the acute renal failure was defined in each case. In patients 80 years of age or older, acute tubular necrosis accounted for 39 percent of the cases of acute renal failure versus 30 percent related to prerenal causes and 20 percent related to obstructive causes. Acute renal failure was preceded by a pre-renal cause with similar frequency in each of the three groups. The changes in serum creatinine were similar in all three age groups. Diuretic use was also similar among the three groups. Patients who were very elderly were less likely to have hemodialysis prescribed than were patients in the 65- to 79-year-old age group. A stratified analysis showed that age was not significantly related to mortality in any of the three groups. When the more serious cause of acute renal failure, acute tubular necrosis, was considered alone, the risk of dying was again not higher in the older patients. Poor prognosis was associated with sustained hypotension and the need for dialysis, but not with oliguria.
Although the incidence of acute renal failure is higher in very elderly patients, the clinical course and mortality rates were not different when compared with younger cohorts. The authors conclude that age alone should not be used in determining if patients with acute renal failure should receive certain treatments, such as dialysis.