Table 2.
Hemoglobin A1c Outcomes and Number and Duration of Hypoglycemic, Hyperglycemic, and Normoglycemic Eventsa
| Outcome | SMBG | CGM | Meta-estimate | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| HbA1c baseline | HbA1c study end | ∆ HbA1c from baseline | p value ∆ HbA1c from baseline | HbA1c baseline | HbA1c study end | ∆ HbA1c from baseline | p value ∆ HbA1c from baseline | p value CGM versus SMBG | ∆ HbA1c from baseline (%) [95% CI]b | p value absolute ∆ HbA1c from baseline | |
| All studies, n = 14 | 8.3 ± 0.7 | 8.0 ± 0.6 | -0.2 ± 0.3 | 0.006 | 8.3 ± 0.8 | 7.8 ± 0.6 | -0.5 ± 0.5 | 0.002 | 0.006 | -0.3[-0.3, -0.2] | <0.0001 |
| Duration of intervention | |||||||||||
| 4–8 weeksc | 8.9 ± 0.7 | 8.6 ± 0.8 | -0.3 ± 0.2 | 0.04 | 9.0 ± 0.8 | 8.6 ± 0.7 | -0.5 ± 0.2 | 0.03 | 0.1 | -0.2[-0.3, 0.01] | 0.06 |
| 12–16 weeksc | 8.2 ± 0.7 | 7.9 ± 0.6 | -0.3 ± 0.4 | 0.02 | 8.3 ± 0.8 | 7.7 ± 0.6 | -0.6 ± 0.5 | 0.01 | 0.01 | -0.3[-0.3, -0.2] | <0.0001 |
| 24–26 weeksc | 8.0 ± 0.6 | 7.8 ± 0.5 | -0.2 ± 0.2 | 0.04 | 8.1 ± 0.5 | 7.7 ± 0.4 | -0.4 ± 0.3 | 0.05 | 0.1 | -0.2[-0.3, -0.1] | <0.0001 |
| Age group (years) | |||||||||||
| <25c | 7.8 ± 0.6 | 7.8 ± 0.4 | -0.1 ± 0.2 | 0.003 | 7.8 ± 0.9 | 7.5 ± 0.6 | -0.3 ± 0.4 | 0.05 | 0.04 | -0.2[-0.3, -0.2] | <0.0001 |
| ≥25c | 8.9 ± 0.6 | 8.5 ± 0.8 | -0.4 ± 0.2 | 0.2 | 9.0 ± 0.4 | 8.3 ± 0.6 | -0.7 ± 0.4 | 0.02 | 0.01 | -0.3[-0.4, -0.2] | <0.0001 |
| Monitoring scheme | |||||||||||
| Intermittentc | 8.7 ± 0.6 | 8.4 ± 0.6 | -0.3 ± 0.2 | 0.02 | 8.7 ± 0.8 | 8.2 ± 0.6 | -0.6 ± 0.4 | 0.03 | 0.04 | -0.3[-0.4, -0.2] | <0.0001 |
| Continuousc | 8.0 ± 0.8 | 7.8 ± 0.4 | -0.2 ± 0.4 | 0.06 | 8.0 ± 0.8 | 7.6 ± 0.6 | -0.6 ± 0.5 | 0.02 | 0.03 | -0.4[-0.5, -0.2] | <0.0001 |
| Type of CGM | |||||||||||
| Retrospective CGMc | 8.6 ± 0.5 | 8.3 ± 0.5 | -0.3 ± 0.3 | 0.03 | 8.7 ± 0.8 | 8.1 ± 0.5 | -0.5 ± 0.4 | 0.04 | 0.06 | -0.3[-0.4, -0.2] | <0.0001 |
| Real-time CGMc | 8.0 ± 0.8 | 7.9 ± 0.7 | -0.2 ± 0.4 | 0.06 | 8.0 ± 0.8 | 7.6 ± 0.7 | -0.4 ± 0.5 | 0.02 | 0.03 | -0.3[-0.5, -0.2] | <0.0001 |
| Outcome | Mean SMBG value | Mean CGM value | p value CGM versus SMBG | p value weighted mean difference [95% CI]d | p value weighted mean difference |
|---|---|---|---|---|---|
| Hypoglycemic events (episodes/day BG ≤ 70 mg/dl)c | 0.52 ± 0.63 | 0.52 ± 0.52 | 0.5 | 0.01 [-0.21,0.23] | 0.1 |
| Duration of hypoglycemia (min/day BG ≤ 80 mg/dl)c | 89.53 ± 19.22 | 75.34 ± 39.21 | 0.1 | -15.2 [-20.3, -10.1] | <0.0001 |
| Duration of profound hypoglycemia (min/day BG ≤55 mg/dl)c | 30.63 ± 14.09 | 27.65 ± 31.10 | 0.2 | -8.8 [-11.8, -5.7] | <0.0001 |
| Duration of normo-glycemia (min/day BG = 71–180 mg/dl)e | 751.44 ± 263.67 | 810.06 ± 286.40 | 0.05 | 67.17 [24.06, 107.49] | <0.0001 |
| Duration of hyperglycemia (min/day BG ≥ 240 mg/dl)e | 217.53 ± 152.94 | 172.26 ± 125.90 | 0.04 | -45.3 [-65.5, -25.0] | <0.0001 |
a
Data are weighted mean ± standard error of the mean.
b
Meta-estimate is the absolute ∆ HbA1c generated from the difference between end of study HbA1c and baseline HbA1c for CGM and SMBG groups where the value for each study is weighted by the inverse variance.
c
Based on random effects meta-analysis.
d
Weighted mean difference is generated from the difference between the CGM and SMBG groups weighted by inverse variance.
e
Based on fixed effects meta-analysis.