Only one in four diabetic patients participating in the Malay Eye Study achieved optimal glycemic control and one in eight achieved optimal blood pressure controls, and these numbers were even lower in individuals with diabetic retinopathy, according to a report in the September 2010 issue of Archives of Ophthalmology.
Olivia S. Huang, B.Sc, of the University of New South Wales, in Kensington, Australia, and her colleagues measured glycemic and blood pressure control among a population-based sample of patients with diabetes and, specifically, those patients with diabetic retinopathy.
Previous studies have predicted that the prevalence of diabetes in Asia will increase from 240 million in 2007 to 380 million in 2025.
The cross-sectional study is based on a population of 3,280 Malay adults aged 40-80 years in Singapore from 2004 to 2006. The researchers identified 768 patients with diabetes, which they defined as non-fasting glucose level of 200 mg/dL or greater, use of diabetic medication, or physician diagnosis. Nearly 1 in 10 had severe diabetic retinopathy.
Overall, the mean glycated hemoglobin (HbA1c) level was 8.0% (range of 4.5%-15.1%) with only 26.9% having an optimal HbA1c level, defined as less than 7%. This number dropped to 17.4% among participants with diabetic retinopathy.
HbA1c of greater than 8% was present in 49.1% of the overall sample, but rose to 61.9% of patients with diabetic retinopathy. Patients who had HbA1c levels greater than 8% were more likely to have diabetic retinopathy vs. those with an HbA1c lower than 8%.
Factors associated with higher odds of suboptimal glycemic control included higher serum cholesterol levels, being previously undiagnosed with diabetes, being treated with oral hypoglycemic agents, and having diabetic retinopathy, the researchers found. Older age, however, was associated with decreased odds of suboptimal control.
Mean systolic and diastolic blood pressure levels were 154.6 mm Hg and 79.2 mm Hg, respectively. Only 13.4% of the overall patients and 10.3% of diabetic patients had optimal blood pressure, defined as 130/80 mm Hg or lower, were achieved in 13.4% patients. In those with diabetic retinopathy, the number dropped to 10.3% (Arch. Ophthalmol. 2010;128:1185-90 [doi:10.1001/archophthalmol. 2010.168]).
Patients with systolic pressure greater than 150 mm Hg were more likely to have diabetic retinopathy than were those with 150 mm Hg or less. A total of 57.3% of the overall sample had optimal diastolic blood pressure levels.
Factors associated with higher odds of suboptimal blood pressure included older age, higher total serum cholesterol levels, higher body mass index, diabetic retinopathy, and posterior subcapsular cataract. Patients who had a previous acute myocardial infarction were less likely to have suboptimal blood pressure control.
Other socioeconomic factors, namely education and income, as well as ocular and systemic factors were not significantly associated with suboptimal blood pressure or glycemic control, the researchers said.
“Our findings present a challenge to health-care policy makers and professionals regarding effective implementation of diabetes care in Asia,” the researchers wrote. Specifically, they need to devise strategies to improve awareness and implement evidence-based guidelines in order to reduce diabetic complications, they added.
Strengths of the study include the population-based sample, masked external grading of retinal photographs with higher proportions of gradable photographs, and standardized measurement of HbA1c and blood pressure, the investigators said. A limitation, they added, was a definition of diabetes based on random blood glucose levels instead of oral glucose tolerance tests.
The authors have no financial disclosures. The study was supported by grants from the National Medical Research Council and Biomedical Research Council and by the Ministry of Health, all in Singapore.