1Black N.Why we need observational studies to evaluate the effectiveness of health careBritish Medical Journal,1996.
2UK Prospective Diabetes Study (UKPDS) group.Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33),1998(9131).
3Cryer PE;Davis SN;Shamoon H.Hypoglycemia in diabetes,2003.
4Patel A;MacMahon S;Chalmers J.Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes,2008.
5DT Gold,B McClung.Approaches to patient education: emphasizing the long-term value of compliance and persistence. The American Journal of Medicine . 2006
6Desouza CV,Bolli GB,Fonseca V.Hypoglycemia,diabetes,andcardiovascular events. Diabetes Care . 2010
7Brierley EJ,Broughton DL,James OFW, et al.Reduced awareness of hypoglycaemia in the elderly despite an intact counterregulatory response. Quarterly Journal of Medicine . 1995
8SL Silverman.From randomized controlled trials to observational studies. The American Journal of Medicine . 2009
9Concato J,Shah N,Horwitz RI.Randomized, controlled trials, observational studies and the hierarchy of research designs. The New England Quarterly . 2000
10UK Prospective Diabetes Study Group.Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. British Medical Journal . 1998
