Insulin - not always a life sentence: Withdrawal of insulin therapy in non-insulin dependent diabetes

The extent of unnecessary insulin administration was assessed by reviewing the records of 350 patients with non-insulin-dependent diabetes (NIDDM). Subjects were included only if previously told that insulin therapy was to be permanent, and not if the need for insulin was known to be temporary (e.g. post-operatively). Fifty-one such patients were identified, 26 men and 25 women, mean age 59.5 (range 24-79) yr, with mean duration of diabetes 10.7 (1-34) yr. Insulin had been administered for a mean of 4.8 (0.3-34) yr in a mean daily dosage of 52.5 (12-280) units. Twenty-nine subjects (57%) were more than 110% of ideal body mass. Insulin therapy was ceased on an outpatient basis, using self blood glucose monitoring in nearly all cases. Mean duration of follow-up since ceasing insulin is 16 (3-48) months. Body mass in overmass subjects fell from (mean ± S.D.) 92.3 ± 20.5 to 82.1 ± 17.8 kg (p < 0.001). Mean HbAl level fell from 12.0 ± 2.2 to 11.0 ± 2.0% (p < 0.05). Sixteen patients are currently treated with diet, and 35 require diet and oral hypoglycemic agents. It appears that insulin therapy in NIDDM is often commenced for 'dietary failure' rather than true secondary failure of oral hypoglycemic agents. Despite progressive increase in dosage, insulin may not improve diabetic control, and may cause weight gain. A management program of diet and exercise, based on self blood glucose monitoring allows reduction in dosage and withdrawal of insulin without hospitalization. The prospect of ceasing insulin enhanced patient motivation, and although initially apprehensive, patients were delighted with the freedom from injections, weight loss and improved diabetic control. We identified 14.6% of 350 subjects with NIDDM diagnosed initially on clinical grounds, and confirmed with estimation of fasting serum C-peptide level. With more extensive use of this assay, a higher rate of unnecessary insulin therapy may emerge.