Comparative accuracy of 1-hour post-load plasma glucose, glycated albumin, and conventional glycemic measures for the diagnosis of type 2 diabetes mellitus: a systematic review and network meta-analysis.

Objective: The International Diabetes Federation has proposed 1-hour plasma glucose (1-h PG) as a potential indicator for the diagnosis of type 2 diabetes mellitus (T2DM). This study aimed to systematically compare the diagnostic performance of 1-h PG, glycated albumin (GA), fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), and the combined HbA1c-or-FPG strategy for identifying T2DM using a network meta-analysis of diagnostic test accuracy. Methods: We systematically searched PubMed, Embase, Web of Science, the Cochrane Library, Scopus, and gray literature for studies evaluating the diagnostic accuracy of 1-h PG, GA, FPG ≥126 mg/dL, HbA1c ≥6.5%, and the combined HbA1c-or-FPG strategy for identifying T2DM, with 2-hour plasma glucose (2-h PG) ≥200 mg/dL during the oral glucose tolerance test (OGTT) as the reference standard. Data extraction and quality assessment were performed independently by two reviewers according to predefined criteria. Statistical analyses were conducted using the Stan package in R and Stata 14.0. Results: A total of 78 studies involving 183,902 participants were included. The network meta-analysis showed that the pooled sensitivity of 1-h PG, GA, FPG, HbA1c, and the combined HbA1c-or-FPG strategy was 0.87 [95% credible interval (CrI), 0.82-0.91], 0.53 (95% CrI, 0.36-0.71), 0.51 (95% CrI, 0.47-0.55), 0.53 (95% CrI, 0.47-0.58), and 0.64 (95% CrI, 0.54-0.73), respectively. The corresponding pooled specificity values were 0.88 (95% CrI, 0.82-0.92), 0.86 (95% CrI, 0.71-0.95), 0.96 (95% CrI, 0.95-0.97), 0.92 (95% CrI, 0.89-0.94), and 0.89 (95% CrI, 0.81-0.95). The pooled positive likelihood ratios (LR+) were 7.68 (95% CrI, 4.97-11.28) for 1-h PG, 4.39 (95% CrI, 1.86-9.30) for GA, 12.63 (95% CrI, 9.33-16.01) for FPG, 6.75 (95% CrI, 4.81-9.05) for HbA1c, and 6.28 (95% CrI, 3.25-11.26) for the combined strategy. The pooled negative likelihood ratios (LR-) were 0.15 (95% CrI, 0.11-0.20), 0.55 (95% CrI, 0.36-0.74), 0.51 (95% CrI, 0.47-0.55), 0.52 (95% CrI, 0.46-0.57), and 0.41 (95% CrI, 0.31-0.53), respectively. The pooled diagnostic odds ratios (DORs) were 52.44 (95% CrI, 30.17-84.00), 8.53 (95% CrI, 2.70-20.94), 24.94 (95% CrI, 17.90-32.30), 13.15 (95% CrI, 8.94-18.51), and 15.83 (95% CrI, 6.62-31.47), respectively. The areas under the summary receiver operating characteristic curves (SROC-AUCs) were 0.757, 0.714, 0.717, 0.706, and 0.726, respectively. Sensitivity analyses restricted to low-risk-of-bias studies and studies using a 1-h PG threshold ≥11.6 mmol/L, as well as subgroup analyses stratified by general and high-risk populations, yielded results and rankings broadly consistent with the primary analysis. Pairwise meta-analysis findings were also generally consistent with those from the network meta-analysis. Conclusions: Among the evaluated diagnostic measures, 1-h PG appeared to provide the best overall diagnostic performance for T2DM, with the highest sensitivity, lowest LR-, and highest DOR. It performed better overall than GA, FPG, HbA1c, and the combined HbA1c-or-FPG strategy. By contrast, FPG showed the highest specificity and LR +. The consistency of the findings across sensitivity analyses, subgroup analyses, and pairwise meta-analysis supports the robustness of the main results. However, given the residual heterogeneity across included studies in terms of study design, population characteristics, and diagnostic thresholds, these findings should be interpreted with caution and confirmed by further large-scale, high-quality studies.