An HbA1c level of more than 9% is associated with worse clinical outcomes in patients with chronic kidney disease who are not dependent on hemodialysis, according to data from a recent study.
The researchers from the University of Alberta in Edmonton, Canada, also found that HbA1c levels of less than 6.5% are associated with excess mortality.
“Our findings are consistent with the hypothesis that better glycemic control in patients with stage III to IV chronic kidney disease tends to improve clinical outcomes, but overly intensive therapy may be harmful,” the researchers wrote.
The study included 23,296 participants with diabetes who also had an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2. All of the participants had a serum creatinine measurement taken as part of routine care in Alberta from 2005 to 2006. They were classified in groups by their first HbA1c measurement: HbA1c level of less than 7%; HbA1c level from 7% to 9%; and HbA1c level of more than 9%. The researchers used Cox regression models to assess associations between HbA1c level and death, progression of kidney disease, new end-stage renal disease, cardiovascular events and all-cause hospitalization.
A higher HbA1c level was strongly and independently associated with all of the outcomes (P<.001). A lower HbA1c level was also associated with an increased risk of mortality. Among those with a baseline eGFR of 30 mL/min/1.73 m2 to 59.9 mL/min/1.73 m2, the risk for end-stage renal disease increased by 22% in those with an HbA1c level of 7% to 9% and by 152% in those with an HbA1c level of more than 9% (P<.001).