Table A2.
Limitations on the Evidence of the Comparative Effectiveness of MDI Versus CSII in Pregnant Women with Preexisting Type 1 Diabetes
| Outcome | Precision | Consistency | No. of studies/No. of good quality studies | Main findings |
|---|---|---|---|---|
| Cesarean section rates | Precise | Consistent | 6 (All OBS)/0 | Meta-analysis of three retrospective cohort studies comparing CSII with MDI that used insulin analogues in the MDI arm showed a combined relative risk of 1.01 (95% CI, 0.90 to1.14; see Fig. 2a).18,19,21 Including studies that allowed regular insulin to be used in the MDI arm did not change the results. |
| Maternal hypoglycemia | Imprecise | Consistent | 4 (All OBS)/0 | Meta-analysis of two retrospective cohort studies showed no difference in the rate of maternal hypoglycemia for CSII compared with MDI: combined relative risk of 0.77 (95% CI, 0.18 to 3.34).18,19 Including studies that allowed regular insulin to be used in the MDI arm did not change the results. |
| Maternal weight gain | Cannot determine | Consistent | 3 (All OBS)/0 | There was no difference in weight gain between the CSII and MDI intervention groups in all three reported studies. The mean between-group difference in weight gain was 1.9 kg (95% CI, −0.9 to 4.7 kg) in one study.18 The other study reported a median weight gain of 13.5 kg in the CSII group and 13.9 kg in the MDI group.20 |
| Ketoacidosis | Imprecise | Unknown | 1 (All OBS)/0 | One study reported that there were two episodes of ketoacidosis (4.7%) in the MDI arm and one episode (1.1%) in the CSII arm.19 |
| Other maternal outcomes | NA | NA | 0/0 | We did not include any studies that evaluated maternal mortality, microvascular or macrovascular disease, QOL, or any of the process measures. |
| Gestational age at delivery | Cannot determine | Consistent | 5 (All OBS)/0 | Gestational age at delivery ranged from 36.3 weeks to 38 weeks for MDI and from 36.3 weeks to 38 weeks for CSII, and there was no significant difference between the MDI and CSII groups.16–19,21,22 |
| Neonatal hypoglycemia | Imprecise | Consistent | 6 (All OBS)/0 | Meta-analysis of three retrospective cohort studies that used only insulin analogues in the MDI arm for frequency of neonatal hypoglycemia showed a combined relative risk of neonatal hypoglycemia for CSII compared with MDI of 0.97 (95% CI, 0.51 to 1.84; see Fig. 3a).18,19,21 Meta-analysis of three retrospective cohort studies that allowed regular insulin in the MDI arm showed a combined relative risk for neonatal hypoglycemia for CSII compared with MDI of 1.19 (95% CI, 0.65 to 2.17; see Fig. 3a).17,20,22 |
| Birth weight | Cannot determine | Unknown | 5 (All OBS)/0 | Meta-analysis of three retrospective cohort studies that used only insulin analog in the MDI arm showed a combined mean between-group difference in birth weight for CSII compared with MDI of 91.52 g, but this difference was not statistically significant (95% CI, −73.28 to 256.31 g; see Fig. 3b).18,19,21 Meta-analysis of two retrospective cohort studies that allowed regular insulin in the MDI arm showed a combined mean between-group difference in birth weight for CSII compared with MDI of −24.80g, but this difference was not statistically significant (95% CI, −245.58 to 195.99 g; see Fig. 3b). |
| Major congenital anomalies | Imprecise | Unknown | 2 (All OBS)/0 | Meta-analysis for only two retrospective cohort studies for major congenital anomalies showed a pooled RR of 2.12 favoring MDI that was not significant (95% CI, 0.38 to 11.77).19,20 |
| Minor congenital anomalies | Cannot determine | Unknown | 3 (All OBS)/0 | Three studies found no difference in minor congenital anomalies between the MDI and CSII groups. There were no minor congenital anomalies in either group in two studies,16,18 and rates of minor congenital anomalies and pregnancy termination rates were 2.3% (2/86 patients) in the MDI group and 13% (4/30 patients) in the CSII group (p=0.05).17 |
| NICU admissions | Imprecise | Unknown | 2 (All OBS)/0 | Meta-analysis on two retrospective cohort studies for admission to the neonatal intensive care unit showed a pooled RR of 0.84 that was not significant (95% CI, 0.43 to 1.68).18,19 |
| Preterm delivery | Imprecise | Unknown | 6 (All OBS)/0 | Meta-analysis of the three retrospective studies comparing CSII with MDI with insulin analogues showed a combined relative risk of 0.91 (95% CI, 0.59 to 1.39; see Fig. 3e).18,19,21 Meta-analysis of the three retrospective studies comparing CSII with MDI with regular insulin showed a combined relative risk of 1.21 (95% CI, 0.69 to 2.13; see Fig. 3e).17,20,22 |
| Still birth rates | Cannot determine | Unknown | 4 (All OBS)/0 | Four studies reported on still birth rates. Three reported that there were no still births in either group,16,18,20 and one study reported having one still birth in MDI group.17 |
| Neonatal mortality | Cannot determine | Unknown | 3 (All OBS)/0 | Three studies reported on neonatal mortality rate. Each group had one neonatal death in one study,17 no neonatal deaths in either group in another,16 and a 0% neonatal mortality rate in the MDI group and 2.7% rate in the CSII group in a third study.20 |
| Perinatal mortality | Cannot determine | Unknown | 1 (All OBS)/0 | One study reported a 0% perinatal mortality rate in MDI group and a 2.7% rate in CSII group.20 |
| Birth trauma | NA | NA | 0 | We did not include any studies that reported on birth trauma. |
CI, confidence interval; CSII, continuous subcutaneous insulin infusions; g, grams; HbA1c, hemoglobin A1c; kg, kilograms; MDI, multiple daily injections; NICU, neonatal intensive care unit; OBS, observational study; QOL, quality of life; RR, relative risk.
The strength of the evidence was defined as follows: High, high confidence that the evidence reflects the true effect. Further research is unlikely to change our confidence in the estimate of the effect. Moderate, moderate confidence that the evidence reflects the true effect. Further research may change our confidence in the estimate of the effect and may change the estimate. Low, low confidence that the evidence reflects the true effect. Further research is likely to change our confidence in the estimate of the effect and is likely to change the estimate. Insufficient, evidence is unavailable.