Random Blood Glucose Estimation in Type 2 Diabetes: Does it Reflect Overall Glycaemic Control?

The relationship between clinic‐measured random blood glucose and glycated haemoglobin was investigated in 204 non‐insulin‐dependent diabetic patients to determine the value of random blood glucose on management decisions in these patients. Treatment was with diet alone in 104 patients (51%: Group 1), and diet and oral hypoglycaemic agents in 100 patients (49%: Group 2). Random blood glucose and glycated haemoglobin were lower in Group 1 than Group 2 (10.9 ± 4.0 vs 13.0 ± 4.0 mmol l−1, p < 0.001, and 8.5 (7.8–10.2) vs 9.6 (8.1–11.0)%, p < 0.01, respectively), and there was a positive correlation between random blood glucose and glycated haemoglobin in both groups (rGroup1 = 0.76, and rGroup2 = 0.54, both p < 0.001). In Group 1, 48 (46%) patients had a random blood glucose < 10 mmol l−1 and all but 2 of these had a glycated haemoglobin of < 10%. Thus, random blood glucose < 10 mmol l−1 was 96% sensitive for glycated haemoglobin < 10%. In Group 2 the same sensitivity was 92%. These data suggest that clinic‐measured random blood glucose levels below 10.0 mmol l−1 predict acceptable overall glycaemic control in non‐insulin‐dependent diabetic patients, particularly in those on diet alone. However, a clinic‐measured random blood glucose above 10 mmol l−1 was of limited value in predicting glycated haemoglobin values above 10% and a blood glucose cut‐off of 14 mmol l−1 appeared more useful. Where resources are limited, clinic random blood glucose estimation may allow clinicians to use glycated haemoglobin measurements more discriminately.