Thomas et al. report on the value of early detecting impaired renal function. This excellent article clarifies how often chronic renal failure is underestimated and that early diagnosis of renal function by measuring serum creatinine alone is low in sensitivity, but is none the less important to recognize in an early, easily treatable stage. The authors refer to the most important causes of renal function impairment, such as hypertension and diabetes. We wish to emphasize the value of recognizing renal impairment also in tumor patients, in whom it is necessary to diagnose this condition as early as possible due to our administration of nephrotoxic chemotherapy agents. Owing to our increasing life expectancy, tumor patients constitute an important and increasing larger growing patient cohort.
We examined renal function in 167 hematology and oncology patients by measuring serum creatinine, Cystatin-C, and estimated glomerular filtration rate (eGFR according to the Cockcroft-Gauld [CG] equation and the MDRD [modification of diet in renal disease] equation). We found mild renal failure (eGFR <90mL/min/1.73m2) in 52% and chronic kidney disease (CKD) stages 3–5 in 22% of patients. The MDRD equation had higher accuracy than the CG equation, which confirms that the MDRD formula has advantages also in cancer patients with often impaired renal function. Measuring Cystatin-C did not add much to our sensitive assessment of renal function measurement provided by the eGFR. In patients with impaired renal function, additional comorbidities and cardiovascular risks were identified (1). These results were verified in 198 patients with multiple myeloma in whom mild, moderate (eGFR <60mL/min/1.73m2), and severe renal failure (CKD stages 4 and 5) was present in 58%, 29%, and 12%, respectively. A deterioration in renal function was also clearly associated with impaired progression free survival and overall survival (OS). Multivariate analysis confirmed the eGFR as an important risk factor, this allowing to create a new risk stratification model with broad availability and cost efficacy: combination of eGFR – as the most essential multivariate risk factor – and ß2-microglobulin (ß2-MG) permitted to define three groups: with 0, 1 or 2 risk factors, median OS was largely different with 71, 48 and 24 months, respectively. This suggests that this new MM-score may be useful to improve risk prediction in MM which was tested in another data set of 127 and subsequently 466 consecutively treated myeloma patients, again confirming the relevance of assessing the eGFR and eGFR-ß2-MG score (3).
Prof. Dr. med. Monika Engelhardt
Dr. med. Martina Kleber
79106 Freiburg, Germany
|1.||Kleber M, Cybulla M, Bauchmüller K, Ihorst G, Koch B, Engelhardt M: Monitoring of renal function in cancer patients: an ongoing challenge for clinical practice. Ann Oncol 2007; 18: 950–8. MEDLINE|
|2.||Kleber M, Ihorst G, Deschler B, et al.: Detection of renal impairment as one specific comorbidity factor in multiple myeloma: multicenter study in 198 consecutive patients. Eur J Haematol 2009; Jul 14. [Epub ahead of print.] MEDLINE|
|3.||Terhorst M, Kleber M, Ihorst G, De Pasquale D, Engelhardt M: Comparison of 4 previously established, but highly different comorbidity scores (Kaplan Feinstein Index [KF], Charlson-Comorbidity Index [CCI], Satariano Index [SI], Hematopoietic cell transplantation-specific comorbidity index [HCT-CI]) identifies the KF and HCT-CI as most relevant, but use of an easily applied 3-risk-factor (Kleber)-score suggests to even more effectively predict progression-free- and overall-survival differences in multiple myeloma (MM) patients (pts). Blood 2009; 114: 1797. MEDLINE|
|4.||Thomas C, Thomas L: Renal failure-measuring the glomerular |
filtration rate [Niereninsuffizienz – Bestimmung der glomerulären Funktion]. Dtsch Arztebl Int 2009; 106(51–52): 849–54.