血液透析患者に対する簡便な内因性インスリン分泌能検査法の検討 A simple method of evaluating endogenous insulin secretory function during hemodialysis session

糖尿病性腎症による透析患者は近年増加が著しく，これらの患者の糖代謝動態を把握する上で，内因性インスリン分泌能を評価することは重要である．経静脈内ブドウ糖負荷による急性インスリン分泌反応の測定により，患者自身の内因性インスリン分泌能を評価することはすでに確立された方法であるが，今回われわれはこれを血液透析施行中に行うことで同様に評価可能か否か検討した．血液透析患者19名に対し，非透析日の早朝空腹時に50％ブドウ糖20mLを1分間で静注負荷し，静注前，5分後，15分後の血糖（GLU）と血清インスリン（IRI）およびC-ペプチド（CPR）を測定した．同一患者で血液透析施行中の昼食前，または夕食前に体外循環回路より同様に行い，ブドウ糖負荷前後のGLUとIRIおよびCPRの濃度変化（5′Δ，15′Δ）を両者で比較した．その結果，血液透析施行中検査と非透析日早朝空腹時検査の相関関係は，5′ΔIRI（r＝0.952，p<0.0001），15′ΔIRI（r＝0.827，p<0.0001），5′ΔCPR（r＝0.781，p<0.0001），15′ΔCPR（r＝0.725，p<0.001）といずれも良好であり，とりわけ5′ΔIRIが最も強い相関を示した．また，糖尿病透析患者では非糖尿病患者にくらべ，5′ΔIRIは有意に低値であった（p＝0.002）．以上より，血液透析患者の内因性インスリン分泌能は，透析施行中の簡便な検査で評価可能と考えられる．

The number of diabetic dialysis patients have remarkably increased in recent years, and the evaluation of endogenous insulin secretory function is important to realize glucose metabolism in these patients. Observation of insulin secretion response after rapid intravenous injection of glucose has already been established as a method of evaluating endogenous insulin secretory function. We studied whether endogenous insulin secretory function can be evaluated by intravenous glucose tolerance test performed during a hemodialysis session. Nineteen patients with end-stage renal disease receiving maintenance hemodialysis were administered 10g of glucose intravenously over 1 minute in the fasting state on the early morning of a non-dialyzing day, and blood glucose (GLU), serum insulin (IRI) and C-peptide (CPR) were measured before and 5 and 15 minutes after the glucose load. Similarly, the test was carried out in the same patients during a hemodialysis session just before lunch or supper, using an external circulation circuit, and the values were compared with those obtained in the early morning of a non-dialyzing day. There were good correlations between the values of 5′ΔIRI (r=0.952, p<0.0001), 15′ΔIRI (r=0.827, p<0.0001), 5′ΔCPR (r=0.781, p<0.0001) and 15′ΔCPR (r=0.725, p<0.001) obtained by the test in the early morning of a non-dialyzing day and those during the hemodialysis session. Among those, 5′ΔIRI showed the strongest correlation. The mean 5′ΔIRI in diabetic dialysis patients was significantly lower than that of non-diabetics. In conclusion, endogeneous insulin secretory function in dialysis patients can be evaluated by simply performing the test during a hemodialysis session.