LAS VEGAS – Patients with chronic kidney disease appear to be at increased risk for cancer, a study showed.
A retrospective analysis of data on 31,896 participants in ALLHAT (the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) showed that during a mean 4.9 years of in-trial follow-up, 2,529 subjects were diagnosed with various cancers.
Dr. Dhruti P. Chen
The 5-year rate of incident cancer was 7.24 cases per 100 person-years among subjects with a baseline normal estimated glomerular filtration rate (eGFR) greater than 90 mL/min per 1.73 m2. The cancer rate rose with decreasing renal function: 8.38 cases per 100 person-years in patients with a baseline eGFR of 60-89.9, 9.18 per 100 person-years in those with an eGFR of 45-59.9, and 11.58 per 100 person-years in patients with an eGFR below 45 mL/min per 1.73 m2, Dr. Dhruti P. Chen reported at a meeting sponsored by the National Kidney Foundation.
An additional 4 years of follow-up for mortality due to cancer was available through national databases after ALLHAT ended. During the mean total 8.9 years of follow-up, there were 2,338 cancer-related deaths. The 10-year rate of cancer mortality was 7.90 cases per 100 person-years in patients with an eGFR greater than 90; 7.71 in those with an eGFR of 60-89.9; 10.11 per 100 person-years with an eGFR of 45-59.9; and 13.19 per 100 person-years in patients with an eGFR below 45 mL/min per 1.73 m2, added Dr. Chen of the department of medicine at Case Western Reserve University, Cleveland.
In a multivariate analysis adjusted for demographics, body mass index, diabetes, cardiovascular risk factors, blood glucose level, and the antihypertensive agent to which a patient was randomized, the association between chronic kidney disease and incident cancer was attenuated. Nonetheless, having a baseline eGFR below 45 mL/min per 1.73 m2 was independently associated with an adjusted 28% increased risk of incident cancer during 4.9 years of follow-up, compared with those with an eGFR greater than 90, as well as with a 55% increased risk of cancer mortality during 8.9 years of follow-up.
Colon cancer was the only common type of malignancy whose incidence was significantly increased in patients with chronic kidney disease, although Dr. Chen said she didn’t attach much significance to this finding, given the limited number of cancers that accrued.
In an interview, she observed that a post hoc analysis such as this can’t establish causality or the mechanisms involved. She speculated that the most likely explanation for the findings is that patients with impaired kidney function have incomplete removal of various toxins, some of which are oncogenic.
ALLHAT was funded by the National Heart, Lung, and Blood Institute. Dr. Chen reported having no financial conflicts of interest.