Blood thiamine levels in outpatients with diabetes mellitus.

In 46 diabetic outpatients consisting of 20 males and 26 females not given thiamine treatment, the blood thiamine level was 46.9 +/- 28.5 ng/ml (mean +/- SD) and only 23.9% of all cases had a value of more than the normal lower limit (50 ng/ml). Erythrocyte transketolase activity was 443.8 +/- 107.7 micrograms/ml/h and only 20.9% had a value of ore than the normal lower limit (50 micrograms/ml/h), and the erythrocyte TPP effect was 16.6 +/- 13.2%. Moreover, there was a significant positive correlation (r = 0.97) between the blood thiamine level and erythrocyte transketolase activity, and a significant inverse correlation (r = -0.525, r = -0.576) between blood thiamine level and/or erythrocyte transketolase activity and the erythrocyte TPP effect. In 24 diabetic outpatients consisting of 14 males and 10 females given thiamine treatment, the blood thiamine level was 96.5 +/- 44.5 ng/ml/h excluding one case (621.7 ng/ml), and it was higher than the normal lower limit in 83% of all cases. Erythrocyte transketolase activity was 513.9 +/- 133.4 micrograms/ml/h and it was higher than the normal lower limit in 58.3%. Erythrocyte TPP effect was 5.84 +/- 8.39%. There was also a significant positive correlation (r = 0.663) between blood thiamine level and erythrocyte transketolase activity, and a significant inverse correlation (r = 0.0668, r = 0.834) between blood thiamine level and/or erythrocyte transketolase activity and erythrocyte TPP effect. Blood thiamine level and erythrocyte transketolase activity were significantly higher in diabetic outpatients given thiamine treatment than in diabetic outpatients not given thiamine treatment, while the erythrocyte TPP effect was significantly lower in diabetic outpatients given thiamine treatment than in diabetic outpatients not given thiamine treatment. There was no direct relationship between the lowered response of patellar tendon reflex and the biochemical status of thiamine. From the above findings it was concluded that diabetic outpatients tend to have a low blood thiamine level, with low erythrocyte transketolase activity and high erythrocyte TPP effect, and showed marginal thiamine deficiency.