Discussion
Our study found that half of our childhood AML patients developed acute
kidney injury during their course of chemotherapy. AKI most commonly
occurs in the early stages after the beginning of treatment, with a
median time to first episode within one month of treatment initiation.
Age at diagnosis ≥ 10 years, impaired renal function at AML diagnosis,
and septic shock were independent risk factors for AKI.
Pediatric data on the epidemiology of AKI in AML are limited, to our
knowledge, to only two previous reports.10,19 In one
study, the incidence of acute renal failure was found to be
16.2%19; however, since acute renal failure does not
include severe cases of AKI, the incidence of AKI may have been
underreported. The high incidence of AKI found in our study is
consistent with a study by Du Plessis et al, who also used the KDIGO
criteria for defining AKI.10
In studies in both adulthood and childhood AML, one of the common
findings was that older age (more than 10 years in children and more
than 55-60 years in adults) was a significant independent risk factor
for AKI.10,19–21 These results correlated with the
finding of other studies which found that the prognosis of AML gets
worse with increasing age.22,23
We also found impaired initial renal function was strongly associated
with a higher likelihood of one or more AKI incidents during admission
in our study, consistent with a previous report in pediatric cancer
patients from Korea.1 We found 15 AML patients with
impaired initial eGFR at their first AML diagnosis, 12 of whom developed
at least 1 episode of AKI. There were no significant differences in
white blood cell counts or occurrence of tumor lysis syndrome that may
have contributed to kidney damage between patients with impaired eGFR
and patients with normal initial renal function. None of the patients in
our study had had previous investigations for preexisting renal tract
anomalies, so we did not know the exact cause of impaired renal function
in these patients. However, due to the high risk of developing AKI in
impaired renal function patients, nephrotoxic medications should only be
prescribed with caution and renal function should be closely monitored
during treatment in these patients.
Regarding infections, the most common treatment-related toxicity and
main cause of death was sepsis, which has been commonly associated with
AKI in both noncancer and cancer patients.8,24–26 Our
study confirmed a strong association between septic shock and AKI during
the course of chemotherapy, consistent with a previous pediatric AML
study.10 In terms of overall treatment outcomes in our
study, the proportion of patients entering remission was significantly
lower in the AKI group. This finding might be explained by a dose
adjustment of chemotherapy in patients who developed AKI. However, there
were no differences in either relapse or mortality rates between the two
groups. As the only known effective regimens for treating childhood AML
involve aggressive treatment, lowering the intensity of chemotherapy may
be beneficial in some patients, as this should lead to a decrease in
associated infections and subsequent organ dysfunction, including AKI,
and hopefully lead to decreased mortality, which is often related to
organ-failure caused by sepsis rather than AML itself.
In conclusion, half of our childhood AML patients developed AKI during
their chemotherapy treatment. Age ≥ 10 years at diagnosis, impaired
renal function before treatment, and septic shock were independent risk
factors for developing AKI.
Conflict of Interest Disclosure: The authors have no conflicts
of interest relevant to this article to disclose.