A cross-sectional population study was performed in a cohort of 890
non-insulin-dependent diabetes mellitus (
NIDDM) patients residing in the greater Denver metropolitan region. Its purpose was to evaluate the relationship between
insulin and oral
hypoglycemic agents (OHAs) with regard to metabolic control and
diabetic complications. The mean
glycosylated hemoglobin for patients treated with
insulin was 12.0 +/- 0.15% versus 11.4 +/- 0.14% (p < .03) for OHA. The difference in fasting
blood sugar for the
insulin-treated group (195.0 +/- 3.5 mg/dl) versus the OHA-treated group (194.0 +/- 2.9 mg/dl) was not statistically significant. Categorical increases in urinary
albumin excretion were associated positively within
insulin versus OHA
therapy (p < .0001). Patients treated with
insulin therapy had a higher frequency of
peripheral vascular disease (
insulin therapy, 14%; OHA
therapy, 10%; p < .05); neuropathy (
insulin therapy, 55%; OHA
therapy, 37%; p < .0001); and retinopathy (
insulin therapy, 71%; OHA
therapy, 45%; p < .0001). The frequency of
cardiovascular disease was equivalent in the two groups (17% versus 13%). In protocols correcting for diabetes duration,
glycosylated hemoglobin, and gender in a multivariate model, the use of
insulin still was related significantly to increases in urinary
albumin excretion (p < .01), retinopathy (p < .0001), and neuropathy (p < .0008). In a subgroup of individuals with diabetes duration > 10 years (n = 211 for
insulin treatment, n = 118 for OHA treatment), the frequency of neuropathy still was significantly higher in the
insulin group (63% vs 49%; p < .016) as was retinopathy (85% vs 58%; p < .0001). Overt
albuminuria also was more significant in the
insulin-treated patients (p < .04). In summary, the
NIDDM patients treated with
insulin had more nephropathy, retinopathy, and neuropathy than did
NIDDM patients treated with OHA, independent of duration of diabetes, fasting
blood glucose,
glycosylated hemoglobin, age, and blood pressure level. These results in
NIDDM patients may be due to contributions from worse
blood glucose control at an earlier stage in the patients' diabetes and/or the mitogenic, atherogenic, thrombogenic, and vascular permeability effects of
insulin.