To investigate the application of flash glucose monitoring (FGM) system in liver transplant recipients during the early stage after transplantation.

Twenty-eight recipients who got allotransplantation of the liver in the Organ Transplant Center of the First Affiliated Hospital of Sun Yat-sen University from April to August 2019 were included in the study. FGM system (Abbott Laboratories, USA) was used to continuously monitor the interstitial fluid glucose concentration, and fasting blood samples of the recipients were collected in the morning, the venous blood glucose value was measured by automatic biochemical analyzer as a reference to evaluate the accuracy of clinical application of FGM blood glucose value. The R language 3.6.1 software was used for Clarke error grid analysis. Paired t-test or rank sum test was used for FGM results at 1 and 2 weeks after liver transplantation. Pearson correlation analysis was used to compare the correlation between FGM blood glucose values and venous blood glucose values. The mean absolute relative difference (MARD) and determination coefficient r² of the paired data of FGM blood glucose and intravenous blood glucose were calculated to compare the consistency of the two methods. P<0.05 was considered statistically significant.

The average wearing time of FGM system in 28 recipients was (12.5±2.4) d (7-14 d), and no adverse reactions such as allergy, itching, skin erythea, cyanosis and pain occurred during wearing, and no sensor shedding occurred. During the wearing of the FGM system, the estimated glycated hemoglobin of 28 recipients was (6.7±1.7) %, the glucose level of FGM was (8±3) mmol/L, and the time within the target range was (72±34) %, with the median time below and above the target range being 1% and 8%, respectively. The FGM blood glucose values of 3 recipients was within the target range throughout the whole process, 23 cases were once above the target range, and 14 cases were once below the target range. The blood glucose level of FGM at 2 weeks after transplantation [(8±3) mmol/L] was lower than that at 1 week [(9±4) mmol/L], and the difference was statistically significant (t=2.4, P<0.05). The median time below the target range at 2 weeks after transplantation (1%) was higher than that at 1 week (0%), and the difference was statistically significant (z=-2.5, P<0.05). During wearing the FGM system, 244 pairs of fasting FGM blood glucose values and venous blood glucose values were collected, the average blood glucose level was (7±4) and (8±4) mmol/L respectively, showing a highly positive correlation (r=0.976, P<0.05). The results of Clarke error grid analysis showed that 93% (227/244) and 7% (17/244) of FGM blood glucose values were in zone A and B respectively. MARD=9.8%, r²=0.95.

The clinical application of FGM system in liver transplant recipients during the early stage after transplantation was feasible. Compared with the conventional intermittent peripheral blood glucose monitoring, more abnormal blood glucose events and their duration could be detected. It could help to take favorable treatment to control glucose levels in the best range.