Occurrence of late specific complications in type II (non-insulin-dependent) diabetes mellitus

Abstract

The objective of the present study was to determine the occurrence of late specific complications, i.e., nephropathy, retinopathy, and autonomic neuropathy, in type II (non-insulin-dependent) diabetic subjects with a recent onset and with a disease duration of at least 5 years. The study design comprised of a population-based controlled cross-sectional survey of middle-aged type II diabetic subjects in the City of Tampere, Southwest Finland. The mean (SD) albumin excretion rate per 24 h was found to have increased in recently diagnosed diabetic subjects, i.e., 54 (111) mg ( p < 0.0001), and in long-term diabetic subjects, 134 (479) mg ( p < 0.0001), compared to nondiabetic controls, 16 (19) mg. Microalbuminuria (30 mg/24 h ≤ albumin excretion rate ≤ 300 mg/24 h) was detected in 8% of nondiabetic subjects and in 29% of recently diagnosed subjects and 27% of long-term diabetic subjects. The prevalence of clinical nephropathy (albumin excretion rate > 300 mg/24 h) was 7% in long-term and 4% in recently diagnosed diabetic subjects and zero in nondiabetic subjects. The differences between diabetic and nondiabetic subjects tested for microalbuminuria and clinical nephropathy were significant ( p = 0.02-0.0001) exempting the difference between recently diagnosed female diabetic subjects and nondiabetic female subjects tested for clinical nephropathy. Seventy-five percent of biopsied diabetic subjects with an albumin excretion rate exceeding 100 mg/24 h were found to have diabetic glomerulosclerosis, while the rest had a normal finding. In long-term diabetic subjects the prevalence of nonspecific, background and proliferative retinopathies were present in 40%, 31%, and 8%, respectively. The prevalences for recently diagnosed diabetic subjects were 17%, 6%, and 0%. Nondiabetic subjects displayed some nonspecific retinopathy, i.e., in 6%, and in one subject preretinal hemorrhage and lipid exudates were found, i.e., background retinopathy. The differences for the retinopathies between all the study groups were significant ( p = 0.03-0.0000) except between recent diabetic and nondiabetic subjects for proliferative retinopathy. The mean (SD) values for the age-corrected cardiovascular reflex tests (Valsalva, deep breathing, and orthostatic tests) were for recently diagnosed diabetic subjects 1.48 (0.31), 1.22 (0.15), and 1.21 (0.14) and for long-term diabetic subjects 1.44 (0.27), 1.18 (0.10), and 1.20 (0.15). Nondiabetic subjects had higher values, i.e., 1.58 (0.33), 1.22 (0.12), and 1.24 (0.14), respectively. The differences between the long-term diabetic and nondiabetic subjects were significant ( p = 0.01-0.0001). The difference for the Valsalva test between recently diagnosed diabetic and nondiabetic subjects was also significant ( p = 0.0087). Using cut-off points appearing in the literature for the three tests, “definite or possible” autonomic neuropathy was diagnosed in 12% of long-term, in 8% of recently diagnosed diabetic and in 2% of nondiabetic control subjects. In conclusion, specific diabetic complications were present in a substantial number of cases among recently diagnosed type II diabetic subjects when sensitive tests were utilized. After one decade of diabetes the complications appeared to be even more frequent and severe.