Page 35 - Delaware Medical Journal - July/August 2019

CASE REPORT
such as HbS and HbC, can also interfere with accuracy of A1c detection assay.1
Chronic kidney disease (CKD) is yet another factor that can affect A1c measurement (Table 2). High level
of urea in CKD patients results in carbamylated hemoglobin, which falsely elevates A1c.1 Additionally, CKD patients are commonly anemic, may be on erythropoietin, and may be on dialysis, each of which can affect A1c measurement. Thus, A1c may be of limited utility in patients with CKD, which is a common complication of uncontrolled diabetes.
The case also highlights the association between diabetes and cancer as well
as cancer mortality, which has been
demonstrated by many researchers. The National Health and Nutrition Examination Survey I (NHANES I) analyzed the risk of cancers in a cohort of 14,407 subjects that were followed from the 1970s to 1987. They reported that men with diabetes had increased risk of developing cancer overall, especially colorectal and prostate cancer.4 In another study of 116,488 females that were followed from 1976 to 1998, women with type 2 diabetes had increased incidence of breast cancer compared with women without diabetes.5 The Cancer Prevention Study II (CPS II) followed a cohort
of 1,053,831 adults without cancer at baseline from 1982 to 2008. In this study, diabetes was associated with higher risk of death from cancers of
liver, pancreas, and colon in both men and women.6 A meta-analysis of 23 studies demonstrated that patients diagnosed with cancer who have pre- existing diabetes are at increased risk of all-cause mortality compared to cancer patients who are non-diabetic [HR 1.41; 95% CI 1.28-1.55].7 Therefore, diabetes may not only increase risk of various cancers, but may also increase mortality in patients with cancers.
CONCLUSION
The key learning point of the discussion above is to always consider patient factors that may be affecting A1c when interpreting it. A meticulous workup after suspicion for falsely high or low
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