Developing a Risk Stratification Tool to Predict Patients with Gestational Diabetes Mellitus at Risk of Insulin Treatment: A Cohort Study

TL;DR

This study created a tool to predict which pregnant women with gestational diabetes will need insulin treatment, validated with high accuracy.

Contribution

A novel risk stratification tool for gestational diabetes mellitus patients requiring insulin treatment was developed and validated.

Findings

Higher fasting blood glucose and BMI increase insulin treatment likelihood.

Later diagnosis gestational weeks reduce insulin treatment risk.

The tool has a 94% negative predictive value in identifying low-risk patients.

Abstract

Objectives: We aimed to develop and validate a simple, easy-to-use risk stratification tool to use in the diagnosis of gestational diabetes mellitus (GDM) to triage those more likely to require insulin treatment. Methods: Using an audit of patients with GDM in 2019, multivariable logistic regression was used to select variables and develop a prediction model for insulin requirement. A stratification tool was developed by dichotomising these selected variables; its performance was assessed with an internal cohort from 2021 and externally from patients managed at a separate hospital. Results: Patients with a higher fasting blood glucose concentration (OR 2.41, 95% CI 1.84–3.15) and higher booking body mass index (OR 1.48, 95% CI 1.07–2.03) were more likely to require insulin therapy whilst a later gestational-weeks-at-diagnosis value gave a lower risk of insulin therapy (OR 0.71, 95% CI 0.62–0.81 per week). The low-risk group for insulin requirement was defined thus: fasting blood glucose < 5.6 mmol/L, booking BMI < 30 kg/m2, and gestational weeks at diagnosis ≥ 24 weeks. This classification had a negative predictive value (NPV) of 94% for insulin requirement, with a sensitivity of 84% and specificity of 56% in the development cohort. Similarly, in the internal and external validation cohorts, the NPVs were 93 and 90%, with sensitivity values of 77 and 78%, respectively. Conclusions: This study developed a pragmatic tool with three criteria for stratifying the GDM group not requiring insulin treatment, with successful validation for clinical use.

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