A Cluster Randomized Noninferiority Field Trial of Gestational Diabetes Mellitus Screening

CONTEXT

Although it is well-acknowledged that gestational diabetes mellitus (GDM) is associated with the increased risks of adverse pregnancy outcomes, the optimal strategy for screening and diagnosis of GDM is still a matter of debate.

OBJECTIVE

This study was conducted to demonstrate the noninferiority of less strict GDM screening criteria compared with the strict International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria with respect to maternal and neonatal outcomes.

METHODS

A cluster randomized noninferiority field trial was conducted on 35 528 pregnant women; they were scheduled to have 2 phases of GDM screening based on 5 different prespecified protocols including fasting plasma glucose in the first trimester with threshold of 5.1 mmol/L (92 mg/dL) (protocols A, D) or 5.6 mmol/L (100 mg/dL) (protocols B, C, E) and either a 1-step (GDM is defined if one of the plasma glucose values is exceeded [protocol A and C] or 2 or more exceeded values are needed [protocol B]) or 2-step approach (protocols D, E) in the second trimester. Guidelines for treatment of GDM were consistent with all protocols. Primary outcomes of the study were the prevalence of macrosomia and primary cesarean section (CS). The null hypothesis that less strict protocols are inferior to protocol A (IADPSG) was tested with a noninferiority margin effect (odds ratio) of 1.7.

RESULTS

The percentages of pregnant women diagnosed with GDM and assigned to protocols A, B, C, D, and E were 21.9%, 10.5%, 12.1%, 19.4%, and 8.1%, respectively. Intention-to-treat analyses satisfying the noninferiority of the less strict protocols of B, C, D, and E compared with protocol A. However, noninferiority was not shown for primary CS comparing protocol E with A. The odds ratios (95% CI) for macrosomia and CS were: B (1.01 [0.95-1.08]; 0.85 [0.56-1.28], C (1.03 [0.73-1.47]; 1.16 [0.88-1.51]), D (0.89 [0.68-1.17]; 0.94 [0.61-1.44]), and E (1.05 [0.65-1.69]; 1.33 [0.82-2.00]) vs A. There were no statistically significant differences in the adjusted odds of adverse pregnancy outcomes in the 2-step compared with the 1-step screening approaches, considering multiplicity adjustment.

CONCLUSIONS

The IADPSG GDM definition significantly increased the prevalence of GDM diagnosis. However, the less strict approaches were not inferior to other criteria in terms of adverse maternal and neonatal outcomes.

Comparative induction of controlled circulation by magnesium and remifentanil in spine surgery

AIM: To evaluate the efficacy of magnesium sulfate (MGS) in comparison with remifentanil for induction of relative hypotension in posterior fusion of spine (PSF).

METHODS: In this randomized clinical trial, 40 patients with the American Society of Anesthesiologists I and II physical status undergoing lumbar PSF were randomized to receive remifentanil (REM) 0.15 μg/kg or MGS 50 mg/kg for controlled hypotension. The administering anesthesiologist was blinded to the medication. Continuous infusion was maintained at a fixed volume rate to deliver precalculated doses of either study drugs. All other aspects of anesthesia and surgery were similar in the two groups. The target mean arterial pressure (MAP) range used in this study was 60-70 mmHg. In the course of surgery, the hemodynamic variables, volume of blood loss, urine output, fluid intake and surgeon’s satisfaction were recorded. Data was analyzed with SPSS version 13.0 and P values less than 0.05 were considered significant.

RESULTS: Twenty patients in the MGS group and 19 patients in the REM group were studied. There was no difference between the two groups in the hemodynamic variables, blood loss, urine output, fluid requirement and surgeon’s satisfaction for exposure. The target MAP was achieved in 75% of Mg and 58% of remifentanil groups. Although a higher number of patients in the REM group required nitroglycerin (42.1%) to reach the target MAP than those in the MGS group (25%), this difference was not statistically significant (P = 0.32).

CONCLUSION: Our findings showed that in patients undergoing lumbar PSF surgery, remifentanil and MGS have a similar hypotensive effect and comparable amount of blood loss without any significant adverse effects.