Excessive HbA1c Testing
Current clinical guidelines for the care of patients with stable type 2 diabetes recommend measuring hemoglobin A1c (HbA1c) once or twice per year. More frequent treatment might result in overtreatment and hypoglycemia.
A study of newly diagnosed diabetes in the Veterans Affairs Administration revealed that 38% of patients were tested at least three times and 4% were tests at least five times per year during the year following a new diagnosis (Laxmisan A, Vaughan-Sarrazin M, Cram P. Repeated hemoglobin A1C ordering in the VA health system. Am J Med 2011;124:342-9). ?
A more recent retrospective study of 31,545 individuals with stable diabetes who were enrolled in commercial insurance and Medicare Advantage between 2001 and 2014 also revealed overtesting for HbA1c ( McCoy RG, HbA1c overtesting and overtreatment among US adults with controlled type 2 diabetes (BMJ 2015;351:h6138 doi: 10.1136/bmj.h6138).
Patients included in the study had two consecutive HbA1c results below 7.0% within a 24 month period. One third of these patients did not receive any glucose lowering drugs. Others were treated with one to three drugs, but none required insulin. More than half of these patients were tested three to four times per year and 5.8% were tested more than five times per year. Patients who were overtested tended to be older, have more comorbid conditions and prescribed more glucose lowering medications.
Most patients (81.6%) did not have their treatment altered after the index HbA1c result. However, 13% of patients who were tested three to four times per year and 7% who were tested more than 5 times per year received intensified treatment including additional non-insulin glucose lowering drugs or insulin. These outcomes suggest that patients whose HbA1c was already less than 7% were overtreated. Intensive glucose lowering treatment has been linked to adverse health outcomes including hypoglycemia, cardiovascular events and mortality.
