Diagnostic accuracy of fasting plasma glucose as a screening test for gestational diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE: Fasting plasma glucose (FPG) is suggested as a potential screening test for further confirmatory testing by oral glucose tolerance test (OGTT) for diagnosing gestational diabetes mellitus (GDM). The diagnostic accuracy of FPG has been investigated in several studies with varying results. This meta-analysis is done to evaluate the diagnostic accuracy of FPG for the screening of GDM. MATERIALS AND METHODS: We conducted a systematic search for all studies reporting the diagnostic accuracy of FPG with OGTT as the reference standard in the databases of Medline, Scopus, Cochrane and Embase from inception till January 2020. Quality assessment of diagnostic accuracy studies-2 tool was used to assess the quality of trials. RESULTS: 29 studies with 74.481 patients were included. Eleven studies used the cut-off values of 92mg/dl for FPG to diagnose GDM, whereas 10 studies used the value of 92 mg/dl. The pooled sensitivity and specificity of FPG for cutoff a92 mg/dl was 68.6% (95% CI: 51.8%-81.9%), and 93.2% (95% CI: 80.5%-97.8%) respectively. The AUC was 0.88 (95% CI: 0.79-0.94). The pooled sensitivity and specificity of FPG for cutoff >= 90 mg/dl was 58.5% (95% CI: 41.1%-73.9%), and 89.2% (95% CI: 78.5%-94.9%) respectively. The AUC was 0.83 (95% CI: 0.75-0.91). The overall quality of studies was moderate. CONCLUSIONS: To summarize, our study found that FPG may have a role in the screening of GDM among pregnant women with satisfactory sensitivity and specificity at a cut-off of 92 mg/dl. Further studies exploring its accuracy in different ethnic populations in reference to a standard OGTT are required to strengthen the evidence.