Association of transcription factor 7-like 2 gene (TCF7L2) polymorphisms with stress-related hyperglycaemia (SRH) in intensive care and resulting outcomes: The READIAB study

Objective: The study aimed to evaluate the impact of the single nucleotide polymorphism (SNP) rs7903146 on the transcription factor 7-like 2 (TCF7L2) gene in stress-related hyperglycaemia (SRH), defined as blood glucose≥11mmol/L in at least two blood samples during the first 3 days in the intensive care unit (ICU), and on 28-day and 1-year mortality, and incidence of type 2 diabetes (T2D) at 6 months and 1 year in patients hospitalized in the ICU.

Methods: This prospective observational (non-interventional) multicentre READIAB study, carried out during 2012-2016 in six French ICUs, involved adult patients admitted to ICUs for at least two organ failures; patients admitted for<48h were excluded. During the 3-day ICU observational period, genetic testing, blood glucose values and insulin treatment were recorded.

Main results: The association of rs7903146 with SRH was assessed using logistic regression models. Cox proportional hazards regression models assessed the associations between rs7903146 and mortality and between SRH and mortality, both at 28 days and 1 year. A total of 991 of the 1000 enrolled patients were included in the READIAB-G4 cohort, but 242 (24.4%) had preexisting diabetes and were excluded from the analyses. SRH occurred within the first 3 days in the ICU for one-third of the non-diabetes patients. The association between the rs7903146 polymorphism and SRH did not reach significance (P=0.078): OR_{(peroneTcopy)}: 1.24, 95% CI: 0.98-1.58. A significant association was found between rs7903146 and 28-day mortality after adjusting for severity scores (P=0.026), but was no longer significant at 1 year (P=0.61). At 28 days, mortality was increased in patients with SRH (HR: 2.09, 95% CI: 1.43-3.06; P<0.001), and remained significant at 1 year after adjusting for severity scores (HR: 1.73, 95% CI: 1.32-2.28; P<0.001). On admission, non-diabetes patients with SRH had a higher incidence of T2D at 6 months vs. those without SRH (16.0% vs. 7.6%, RR: 2.11, 95% CI: 1.07-4.20; P=0.030). At 1 year, these figures were 13.4% vs. 9.2%, RR: 1.45, 95% CI: 0.71-2.96; P=0.31). Moreover, the rs7903146 polymorphism was not significantly associated with T2D development at either 6 months (P=0.72) or 1 year (P=0.64).

Conclusion: This study failed to demonstrate any significant association between rs7903146 and SRH. Nevertheless, the issue remains an important challenge, as SRH may be associated with increased rates of both mortality and T2D development.