Tight glycemic control in type 1 diabetes (T1D) is limited by hypoglycemia, while glycemic variability (GV) confers independent risk for the development of diabetes-related complications. We aimed to establish the values for indices of hypoglycemia and GV in T1D Singaporean subjects. One-hundred and thirty one subjects (73% Chinese, 11% Malay, 12% Indian; 48% male) were recruited from a single center. Eighty subjects submitted glucose records performed over 4 weeks. Ryan lability index and HYPO score were calculated in subjects with at least 3 glucose readings/day. Key characteristics, indices of hypoglycemia and GV are summarized in the table.
Hypo score and LBGI were significantly correlated (r=0.63). ADRR and mLI correlated with each other (r=0.79), and with LI (ADRR r=0.72, mLI r=0.93), S.D.(r=0.78 and 0.79), %CV (r=0.45 and 0.56) and HbA1c (r=0.53 and 0.44). LI correlated with S.D. (r=0.58) but not %CV or HbA1c
Our results indicate differences compared to other populations. There were fewer subjects with hypoglycemia than Edmonton (85%), or Korean T1D subjects (71%), with much lower Hypo scores in our cohort (90th percentile of 76 vs. 1047 in Edmonton and 377 in Korean subjects). Ryan LI was comparable to the Edmonton cohort, but ADRR, LI and mLI were lower than Korean T1D subjects. Population-specific values should be established, to determine appropriate cut-offs for access to treatments such as islet transplantation.
Clinical characteristics and glycemic indices
| Characteristic | Results | Glycemic parameters | Results | Hypoglycemia awareness Scores | Results | Glycemic variability Indices | Results |
| Age of diagnosis, years | 19 (12 – 27) | Average HbA1c (%) | 8.2 (7.3 – 9.2) | Clarke score ≥4 | 24.6% | Average daily risk range (ADRR) (n=53) Median (Interquartile range), 90th percentile | 25.0 (17.7 – 37.0), 40.6 |
| Duration of diabetes, years | 14 (8 – 19) | Average Glucose (mmol/L) | 9.2 (8.0 – 11.2) | Gold score ≥4 | 28.3% | Ryan lability index (n843) Median (Interquartile range), 90th percentile | 168.5 (93.3 – 333.6), 432.8 |
| Insulin use (units/kg/day) | 0.77 (0.61 – 0.91) | S.D. (mmol/L) | 4.4 (3.5 – 5.2) | Hypoglycemia Indices | Ryan lability index/no. of BG readings/day (modified Li, mLI) Median (Interquartile range), 90th percentile | 44.6 (27.0 – 63.1), 83.7 | |
Type of insulin regimen (twice daily, 3 times/day, 4 or more/day, insulin pump) (%) | 6.5/17.7/59.7/16.1 | %CV | 37.9 (9.9 – 44.5) | Ryan Hypo score (n=43) Median (Interquartile range), 90th percentile | 13 (0 – 25), 76 | ||
Low blood glucose index (LBGI) (n=80) Median (Interquartile range), 90th percentile | 1.1 (0.5 - 2.1), 3.5 | ||||||
| % patients with at least 1 episode of hypoglycemia < 3 mmol/L | 38.8 |
| Characteristic | Results | Glycemic parameters | Results | Hypoglycemia awareness Scores | Results | Glycemic variability Indices | Results |
| Age of diagnosis, years | 19 (12 – 27) | Average HbA1c (%) | 8.2 (7.3 – 9.2) | Clarke score ≥4 | 24.6% | Average daily risk range (ADRR) (n=53) Median (Interquartile range), 90th percentile | 25.0 (17.7 – 37.0), 40.6 |
| Duration of diabetes, years | 14 (8 – 19) | Average Glucose (mmol/L) | 9.2 (8.0 – 11.2) | Gold score ≥4 | 28.3% | Ryan lability index (n843) Median (Interquartile range), 90th percentile | 168.5 (93.3 – 333.6), 432.8 |
| Insulin use (units/kg/day) | 0.77 (0.61 – 0.91) | S.D. (mmol/L) | 4.4 (3.5 – 5.2) | Hypoglycemia Indices | Ryan lability index/no. of BG readings/day (modified Li, mLI) Median (Interquartile range), 90th percentile | 44.6 (27.0 – 63.1), 83.7 | |
Type of insulin regimen (twice daily, 3 times/day, 4 or more/day, insulin pump) (%) | 6.5/17.7/59.7/16.1 | %CV | 37.9 (9.9 – 44.5) | Ryan Hypo score (n=43) Median (Interquartile range), 90th percentile | 13 (0 – 25), 76 | ||
Low blood glucose index (LBGI) (n=80) Median (Interquartile range), 90th percentile | 1.1 (0.5 - 2.1), 3.5 | ||||||
| % patients with at least 1 episode of hypoglycemia < 3 mmol/L | 38.8 |
A. Koh: None. S.N. Fun: None. E. Yeoh: None.
