Diabetes screening in dialysis populations with a glucose challenge test and continuous glucose monitoring-DIGEST...

People on dialysis are at a higher risk of diabetes mellitus. The oral glucose tolerance test (OGTT) is the gold standard for detecting dysglycaemia, but is cumbersome. This study investigates the OGTT in comparison to the glucose challenge test (GCT) and continuous glucose monitoring (CGM) as a simpler screening tool for people on dialysis.

This single-centre prospective diagnostic cohort study included adults on dialysis at the Antwerp University Hospital without a diabetes history or glucose-lowering therapy. Participants underwent a 50 g-GCT followed by a 75 g-OGTT 8-10 days later, with CGM conducted in between.

Of 50 eligible individuals, 27 declined participation due to the OGTT burden. Thirteen out of 23 participants had dysglycaemia (2 -hr OGTT ≥140 mg/dL or ≥7.8 mmol/L). Those with dysglycaemia had a higher BMI (26.2 ± 3.9 vs. 22.8 ± 3.3 kg/m², p = 0.039), longer dialysis vintage (4.5 ± 2.9 vs. 1.6 ± 1.4 years, p = 0.009), and were less often waitlisted for transplantation (5/13 vs. 10/10, p = 0.005). Fasting glycaemia levels were similar between groups. Dysglycaemia was more common in haemodialysis (HD) than in peritoneal dialysis (PD) (12/14 vs. 1/9, p < 0.001). CGM showed a lower time in range (95 ± 3% vs. 98 ± 3%, p = 0.020) and a higher coefficient of variation (24% vs. 16%, p < 0.001) in those with dysglycaemia. The GCT had an 85% sensitivity and a 70% specificity for dysglycaemia detection. A two-step approach using GCT as a screening tool could avoid 40% of OGTTs while missing 15% of cases. The 5% TATR (time above tight range) revealed a good sensitivity of 92%, but unfortunately, a specificity of 12%.

The GCT may be a practical alternative for dysglycaemia screening in the dialysis population. The 5% TATR showed good sensitivity but poor specificity.