Tan, KCB

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Title Clinical challenge: DiabetesAuthor(s) Tan, KCBCitation Hong Kong Practitioner, 1999, v. 21 n. 8, p. 386-387Issued Date 1999URL http://hdl.handle.net/10722/45095Rights Creative Commons: Attribution 3.0 Hong Kong LicenseCLINICAL CHALLENGEDiabetesQuestion:I read in the British Medical Journal that the UKProspective Diabetes Study Group recently announced theresults of their extensive long term studies on type 2diabetics. What were their main f indings? Are thereimplications for primary care doctors?Comments:The Uni ted K ingdom Prospective Diabetes Study( U K P D S ) was a randomised c o n t r o l l e d t r i a l w h i c hcompared the effects of in tensive glucose control wi thc o n v e n t i o n a l t r e a t m e n t on the r i sk of micro- andmacrovascular complicat ions of type 2 diabetes. Ashypertension was recognized to be an equally importantrisk factor, the effects of t ight blood pressure control wasalso examined in the study. The UKPDS started in 1977and went on for 20 years and the main f ind ings werepublished in four papers in September 1998.1-4The part icipants of the UKPDS were 3867 newlydiagnosed patients with type 2 diabetes who, after threemonths of dietary t reatment , had fas t ing glucose of6 .1-15 mmol/1. They were randomly assigned to anintensive policy with either a sulphonylurea or insulin, orto a conventional policy with diet. During the tr ial , astepwise addition of hypoglycaemic agents was requiredin many patients in the intensive treatment group in orderto ma in ta in fast ing glucose <6.0mmol/l. The dietarypolicy also allowed patients to be given hypoglycaemicagents when the i r g lycaemic goal ( f a s t i ng p lasmaglucose <15 mmol/1) was not met. The failure of diet andthe gradual fa i lures of the hypoglycaemic agents tom a i n t a i n g lycaemic goals resu l ted in s u b s t a n t i a ltherapeutic overlap between comparison groups whichmade subsequent comparisons of the different types oftherapy more difficult. In the blood pressure study, 1148h y p e r t e n s i v e p a t i e n t s w i t h type 2 d iabe tes wererandomised to either tight blood pressure control (targetBP<150/85 mmHg wi th the use of an angio tens inconverting enzyme inhibitor or a beta blocker) or to lesstight control (BP< 180/105 mmHg). For both the diabetesand hypertension management protocols, the primaryoutcomes were "hard" c l in ica l end points , inc lud ingsevere cardiovascular events, vision loss and renal failure.During the trial, HbA,c was reduced by 11% (from7.9 to 7.0) in the intensive treatment group compared toconventional treatment. The reduction was smaller thanthat in DCCT where a reduction of 20% was achieved.5An increased inc idence of hypoglycaemia and moreweight gain were observed in the in tens ive treatmentgroup but in t ens ive t r ea tmen t was associated wi th asignificant reduction of 12% in the risk for any diabetesrelated end points. The observed decrease, however, wasin fact mainly due to the 25% reduction in the risk ofmicrovascular events. There was no effect on diabetes-related mor ta l i ty or all cause morta l i ty . The bloodglucose s tudy therefore shows that t igh t ly controllingblood glucose concentration in type 2 diabetes reduces therisks of microvascular complications but the evidence onmacrovascular complications is inconclusive. As for thebeneficial effects of the different types of treatment,sulphonylureas and insulin seem to produce equally goodresults. The data on metformin is controversial. Forreasons that remain unclear, metformin was effective inreducing impor tant end points in obese pat ients butappeared to work less well in combination with otherdrugs.The blood pressure study showed that tight bloodpressure control in hypertensive patients with type 2diabetes resulted in a s ignif icant reduction in bothdiabetes related end points and diabetes related deaths.Not only was there a significant reduction in the risk ofmicrovascular end points, there was also a 44% decreasein the risk of stroke. Both angiotensin converting enzymeinh ib i to r and beta blocker appeared to be s imilar lye f f ec t i ve in r e d u c i n g the i n c i d e n c e of d iabe t i ccomplications. The study also highlighted the fact thatadditional antihypertensive agents were often required and386Hong Kong Practitioner 21 (8) August 1999CLINICAL CHALLENGEabout one-third of the patients in the tight blood pressurecontrol group required three or more antihypertensiveagents to maintain blood pressure below the target levels.In summary, tight glucose and blood pressure controlin patients with type 2 diabetes is important as it cans i g n i f i c a n t l y reduce the r i sk of the long termcomplications of diabetes. Based on the findings of theUKPDS, it has been suggested that glycaemic goal shouldbe aimed at HbA ) C 7% or lower, taking into account thecondition of the patients, and any reduction of HbA t cfrom a high va lue is impor t an t . In pat ients wi thhypertension, the suggested goal of blood pressure isaround 140/85 mmHg or lower. •References1. UK Prospective Diabetes Study Group. Intensive blood glucose control withsulphonylureas or insulin compared with conventional treatment and risk ofcomplications in patients with type 2 diabetes (UKPDS 33). Lancet 1998;352:837-853.2. UK Prospective Diabetes Study Group. Effect of intensive blood glucosecontrol with metformin on complications in overweight patients with type 2diabetes (UKPDS 34). Lancet 1998:352:854-865.3. UK Prospective Diabetes Study Group. Tight blood pressure control and riskof macrovascular and microvascular complications in type 2 diabetes: UKPDS38. BMJ 1998:317:703-713.4. UK Prospective Diabetes Study Group. Efficacy of atenolol and captoprilin reducing risk of macrovascular and microvascular complications in type2 diabetes: UKPDS 39. BMJ 1998:317:713-720.5. DCCT Research Group. The effect of intensive diabetes treatment on thedevelopment and progression of long-term complications in insulin-dependentdiabetes mellitus: The Diabetes and Complications Trial. N Engl J Med1993:329:978-986.The comments havebeen prepared by Dr. K.C.B. Tan, MD. FRCP(Edin).FHKCP. FHKAM(Med)Associate Professor,Department of Medicine,The University of Hong Kong.ir Clinical Challenges.willorsend your question to:. :; . ''..,, ; • ' . . • T h e Hong K o n g C o l l e g e o f F a m i l y Physicians7th Floor, HKAM Jockey Club Building, 99 Wong Chuk Hang Road, Aberdeen, Hong Kong;:•>.';'.',,..'.-;• ?: Tel : 2528-6618 (4 lines) Fax : 2866-0616387

Clinical challenge: Diabetes

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