Prevalence of visible retinopathy in Saudi diabetics and its correlation with plasma viscosity and histocompatibility antigens

ABSTRACT

Of 2341 Saudi diabetic patients registered with the Diabetic Centre at the Ministry of Health in the eastern province of Saudi Arabia, 957 consecutive patients [IDDM = 87, NIDDM = 870] were examined for evidence of retinal changes. One hundred and fifty three [16%] had background retinopathy; maculopathy was seen in eight cases [1%] and 25 patients [3%] had proliferative retinopathy. Thus the combined prevalence of retinopathy in the present series [i. e. IDDM + NIDDM] was approximately 20%. In IDDM, however, it was seen in 32% cases whereas only 18% of the non-insulin dependent group showed these changes. This is in contrast to two previous reports from this country. Highest incidence of retinopathy [68%] was seen only in those who had the disease for 15 years or more. Furthermore, 43% of all diabetics had raised plasma viscosity [ie > 1.73CP]. A greater proportion of patients with retinopathy had increased plasma viscosity as compared with those who had apparently normal retina suggesting its complementary pathogenetic role. Moderately raised plasma viscosity [1.93 - 2.12CP] was however, seen in association with maculopathy in patients with IDDM. However, 15 of the 17 cases with proliferative retinopathy and all 5 cases with maculopathy in patients with NIDDM had moderately raised plasma viscosity. Two cases with proliferative retinopathy in this group had normal viscosity whereas 5 patients with only background retinopathy had moderately raised plasma viscosity. Similarly 7 cases with no retinal changes had for unknown reasons moderately raised plasma viscosity. In 85% of Saudis with IDDM the disease was associated with either HLA DR3, DR4 or both. The prevalence of HLA DR3 appeared more frequent [65%] in Saudi diabetics than their caucasian counterpart [46%] but it was not significantly associated with the prevalence or the severity of retinopathy