Glucose patterns during an oral glucose tolerance test and associations with future diabetes, cardiovascular disease and all-cause mortality rate
In addition to blood glucose concentrations measured in the fasting state and 2 h after an OGTT, intermediate measures during an OGTT may provide additional information regarding a person’s risk of future diabetes and cardiovascular disease (CVD). First, we aimed to characterise heterogeneity of glycaemic patterns based on three time points during an OGTT. Second, we compared the incidences of diabetes and CVD and all-cause mortality rates among those with different patterns.
Our cohort study included 5861 participants without diabetes at baseline from the Danish Inter99 study. At baseline, all participants underwent an OGTT with measurements of plasma glucose levels at 0, 30 and 120 min. Latent class mixed-effects models were fitted to identify distinct patterns of glycaemic response during the OGTT. Information regarding incident diabetes, CVD and all-cause mortality rates during a median follow-up time of 11, 12 and 13 years, respectively, was extracted from national registers. Cox proportional hazard models with adjustment for several cardiometabolic risk factors were used to compare the risk of diabetes, CVD and all-cause mortality among individuals in the different latent classes.
Four distinct glucose patterns during the OGTT were identified. One pattern was characterised by high 30 min but low 2 h glucose values. Participants with this pattern had an increased risk of developing diabetes compared with participants with lower 30 min and 2 h glucose levels (HR 4.1 [95% CI 2.2, 7.6]) and participants with higher 2 h but lower 30 min glucose levels (HR 1.5 [95% CI 1.0, 2.2]). Furthermore, the all-cause mortality rate differed between the groups with significantly higher rates in the two groups with elevated 30 min glucose. Only small non-significant differences in risk of future CVD were observed across latent classes after confounder adjustment.
Elevated 30 min glucose is associated with increased risk of diabetes and all-cause mortality rate independent of fasting and 2 h glucose levels. Therefore, subgroups at high risk may not be revealed when considering only fasting and 2 h glucose levels during an OGTT.
Keywords30 minute post-OGTT glucose Cardiovascular disease Latent class modelling Mortality Oral glucose tolerance test Plasma glucose curve Type 2 diabetes
1 h plasma glucose
2 h plasma glucose
30 min plasma glucose
Fasting plasma glucose
Insulin sensitivity index
Area under the plasma glucose curve
Incremental area under the plasma glucose curve
AH and DRW are supported by the Danish Diabetes Academy. The Danish Diabetes Academy is funded by the Novo Nordisk Foundation. KF is supported by the Novo Nordisk Foundation.
The raw data underlying this study are restricted to protect participant privacy as required by data protection acts in Denmark. Data will be made available upon request to researchers who qualify for access to confidential data by contacting The Research Centre for Prevention and Health, the Capital Region of Denmark, Email: firstname.lastname@example.org.
The Inter99 study was funded by the Danish Research Councils, Health Foundation, Danish Centre for Evaluation and Health Technology Assessment, Copenhagen County, Danish Heart Foundation, Ministry of Health and Prevention, Association of Danish Pharmacies, Augustinus Foundation, Novo Nordisk, Velux Foundation, Becket Foundation, and Ib Henriksens Foundation. The sponsors were not involved in the design of the study; the collection, analysis and interpretation of data; writing the report; or the decision to submit the report for publication.
Duality of interest
The authors declare that there is no duality of interest associated with this manuscript.
AH was responsible for the data analysis with major contributions from DV. AH wrote the first draft of the manuscript with major contributions from KF. AH, DRW, KF and MB contributed to the original idea for the study. All authors contributed to the interpretation of the data, drafting and critical revision of the manuscript, and approved the final version. AH is the guarantor of this work.
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