Changes Of Blood Lactate Levels And Related Influencing Factors In Diabetes Mellitus Patients Before And After Treatment With Metformin

Objective Metformin is the first-line medication for diabetics.Previous studies have suggested that lactate levels are higher in high-altitude and low-oxygen environments than in low-altitude areas.Then,whether the use of metformin at high oxygen altitudes will increase the patient’s blood lactate level and even cause lactic acid.The risk of acidosis.To this end,we determined changes in blood lactate levels before and after metformin treatment in Tibetan patients with type 2diabetes in Lhasa,and analyzed the influencing factors to provide a theoretical basis for the safety of metformin use in type 2 diabetic patients in high altitude areas.Methods Patients with type 2 diabetes mellitus who were hospitalized in the Department of Endocrinology and Metabolism（average altitude 3 600 m）in the People’s Hospital of Tibet Autonomous Region from November 2016 to December 2017 were selected for the initial diagnosis of type 2 diabetes or those who had not taken metformin before March 3 Metformin treatment was started during hospitalization for 1 week to 1 month（according to patient’s degree of tolerance and drug metabolism,metformin tablets were taken as 0.425 g orally twice daily,and after 2 days it was changed to 0.85 g 2 times/day）,and metformin was measured and analyzed.Before and after the blood lactate levels and the related factors affecting blood lactate levels after taking metformin.Result 1.A total of 132 patients were enrolled in this study,including 98 males and 34 females,with an average age of 52±12 years.The baseline blood lactate level of all subjects was 2.65（1.99 to 4.03）mmol/L;mean blood before and after metformin treatment was used.There was no significant change in lactate levels（2.64（1.98,4.03）mmol/L vs 2.74（1.87,3.97）mmol/L,Z=-0.887,P=0.375）;2.According to the young,middle-aged and old people,the enrolled group was divided into groups.There was no significant difference in blood lactate levels between the groups before and after treatment（all P>0.05）.The blood lactate levels before treatment were divided into normal lactic acid levels（LA<2 mmol/L）,hyperlactatemia（2.00≤LA<4.00 mmol/L）,and severe lactic acidosis（LA≥4.00 mmol/L）.When LA is less than 4.00mmol/l,blood lactic acid increases gradually after taking medicine,and when LA≥4.00 mmol/L,blood lactate level increases after taking medicine when blood lactic acid level rises before taking medicine.The level gradually decreased.With increasing body weight,blood lactate levels increased（r=0.181,P=0.038）.According to the baseline blood oxygen saturation,the enrolled patients were divided into hypoxic group（SpO₂≤90%）and non-hypoxia group（SpO₂>90%）.There was no significant change in blood lactic acid levels before and after taking metformin.3.There were 73 patients（55.3%of the total）with elevated blood lactic acid levels after medication,including baseline blood lactate levels（P<0.001,OR=0.019,95%CI 0.002-0.159）and baseline oxygen saturation（P=0.04,OR=1.092,95%CI 1.004-1.187）is the relevant influencing factor for the increase of blood lactic acid level after taking medicine.Conclusion There was no significant increase in blood lactic acid level after taking metformin in patients with diabetes in Lhasa area.There was no significant increase in blood lactic acid level in patients with advanced age and hypoxia.Changes in blood oxygen saturation and blood lactic acid before administration were the influencing factors.This study shows that the use of metformin to treat type 2 diabetes in highland areas will have no effect on blood lactate levels.