HbA1c is not a valid surrogate marker for all-cause mortality in people with type 2 diabetes, according to a German study.
The research by Heinrich-Heine-University based in Düsseldorf was based on the results of more than 200 randomised trials.
The study published by Acta Diabetologica aimed to validate the HbA1c value as a surrogate for all-cause mortality in people with type 2 diabetes because the measurement of blood glucose levels has been “repeatedly questioned as a valid surrogate marker”.
The effect estimates for HbA1c lowering after treatment as well as reductions in all-cause mortality of randomised trials were extracted from a systematic review and updated.
For the measurement of actual surrogacy, weighted linear regression models with a random intercept for the study effect were used with the all-cause mortality estimate (risk difference and log relative risk) as the outcome and the estimate for HbA1c difference as the covariate.
A total of 346 HbA1c-mortality-pairs from 205 single randomised trials were included in the analysis.
According to the results, the study found: “Regarding the risk difference of all-cause mortality, there was no evidence for surrogacy of the HbA1c value. For the log relative risk, a small positive association between HbA1c and the all-cause mortality estimate (slope 0.129 [95% confidence interval −0.043; 0.302]) was observed. However, there was no sign of valid surrogacy.”
The researchers concluded: “Based on the results of more than 200 randomized trials, HbA1c is not a valid surrogate marker for all-cause mortality in people with type 2 diabetes.”
To access the study, click here.