Is There a Clear Threshold for Fasting Plasma Glucose That Differentiates Between Those With and Without Neuropathy and Chronic Kidney Disease?

Recent studies suggest that no distinct glycemic threshold consistently differentiates individuals with or without retinopathy. The authors sought to determine whether the same was true for other microvascular complications. They studied 5,094 participants with fasting plasma glucose values and concurrent microvascular complications from 4 previous cross-sectional surveys carried out in Singapore (1982-1998) who attended a follow-up examination in 2004-2007. Peripheral neuropathy was diagnosed based on abnormal responses to a 10-g monofilament or neurothesiometer test. Chronic kidney disease was defined in various ways by using albuminuria (urine albumin:creatinine ratio > 30 mu g/mg) and estimated glomerular filtration rate, alone and in combination. Prevalence of peripheral neuropathy was 7.5%. For chronic kidney disease, prevalence of albuminuria only was 10.5%, estimated glomerular filtration rate of < 60 mL/minute per 1.73 m(2) only was 4.1%, and both was 2.1%. Prevalence of peripheral neuropathy and chronic kidney disease gradually increased in relation to fasting plasma glucose, beginning at levels below the existing diagnostic threshold for diabetes mellitus of 7.0 mmol/L (126 mg/dL). For chronic kidney disease, these associations persisted after adjustment for age, gender, ethnic group, and hypertension. Current diagnostic thresholds for diabetes mellitus have limited sensitivity for identifying individuals with these microvascular complications. Ascertaining these individuals may require development and application of novel screening strategies.