Chronic kidney disease, diabetes increase risk for hypoglycemia

Patients with chronic kidney disease and diabetes are at increased risk for hypoglycemia, according to data from a retrospective analysis.

“Hypoglycemia should be viewed as a patient safety event in patients with chronic kidney disease, especially among those who have both CKD and diabetes,” Jeffrey C. Fink, MD, associate professor of medicine of the division of nephrology at the University of Maryland School of Medicine, told Endocrine Today. “Despite the high odds of death associated with hypoglycemia in our study, one has to interpret these findings recognizing the limitations of a secondary analysis of administrative data.”

Researchers identified 243,222 patient records representing treatment at the Veterans Health Administration between Oct. 1, 2004, and Sept. 30, 2005. They examined 2,040,206 records of individual glucose measurements for all patients. The data were linked with inpatient and outpatient information, outpatient event data sets and vital statistics for hypoglycemia or death.

Patients with CKD — defined as an estimated GFR of <60 mL/min per 1.73 m² — were more likely to be older white males and were more likely to have a diagnosis of cancer, diabetes and cardiovascular disease and a higher Charlson comorbidity index when compared with patients without the disease.

Those who experienced hypoglycemia were more likely to be older black males with a greater number of comorbidities and were more likely to have cancer, diabetes, cardiovascular disease and all stages of CKD. Hypoglycemic events were detected in nearly 4% of patients; severe hypoglycemic events were less frequent.

Although patients with CKD alone and diabetes alone had a higher adjusted rate of hypoglycemia compared with those without either disease, patients with both CKD and diabetes had significantly higher rates of hypoglycemia (P<.0001) compared with either disease alone.

Mortality within one day

Researchers said that 2.8% of patients died within one day of the blood draw that recorded glucose values. The presence of CKD with normoglycemia in the inpatient setting slightly increased one-day mortality.

With or without CKD, the odds for death within one day of a hypoglycemic event increased relative to no CKD and a normoglycemic event, for both inpatient and outpatient values. The odds increased with severity of hypoglycemia, according to the published study.

“Of note, there was the tendency of lower odds for death with a hypoglycemic event in the presence of CKD relative to the corresponding severity of hypoglycemia with no CKD,” the researchers wrote.

Classification of hypoglycemic events was higher among inpatient records (4.06%) vs. outpatient records (2.94%). However, the relative increase in the odds for death associated with hypoglycemia was higher in the outpatient setting.

“It is likely that the occurrence of hypoglycemia in patients with diabetes, with or without chronic kidney disease, is largely related to use of diabetic therapies,” the researchers wrote. “However, in the case of patients with chronic kidney disease but without diabetes, the underlying cause for hypoglycemia is not entirely clear. Although the extent to which the increased risk for hypoglycemia is iatrogenic or due to medical therapy is unknown, this metabolic disturbance should be considered an important safety outcome in chronic kidney disease or diabetes populations.” – by Jennifer Southall

Fink J. Clin J Am Soc Nephrol. 2009;doi:10.2215/CJN.00800209.