Research Article: Combined poor diabetes control indicators are associated with higher risks of diabetic retinopathy and macular edema than poor glycemic control alone

Date Published: June 29, 2017

Publisher: Public Library of Science

Author(s): Eva K. Fenwick, Jing Xie, Ryan E. K. Man, Charumathi Sabanayagam, Lyndell Lim, Gwyn Rees, Tien Y. Wong, Ecosse L. Lamoureux, Andrew W. Taylor.

http://doi.org/10.1371/journal.pone.0180252

Abstract

To examine the association of individual and combined indicators of diabetes control with diabetic retinopathy and diabetic macular edema.

In this clinical, cross-sectional study, 613 adults with type 2 diabetes (372 any diabetic retinopathy; 183 any diabetic macular edema) were examined. Diabetic retinopathy was assessed from fundus photographs; diabetic macular edema from Ocular Coherence Tomography scans; and HbA1c and serum lipid values from fasting blood samples. Poor glucose control was defined as HbA1c≥7%; poor blood pressure control as SBP≥130/DBP≥80; and poor lipid control as total cholesterol:HDL ratio≥4.0. The association of poor glucose control, poor blood pressure control and poor lipid control alone and in combination (poor glucose & blood pressure control; poor glucose & lipid control; poor blood pressure & lipid control; and poor glucose, blood pressure & lipid control) with diabetic retinopathy/diabetic macular edema was examined using multiple logistic regression models.

Patients’ mean±standard deviation age was 64.9±11.6 years (57% male). In adjusted models, compared to those with good control of all indicators (n = 99, 18.3%), the odds ratio (95% Confidence Interval) of having any diabetic retinopathy was 2.44 (1.34–4.46), 3.75 (1.75–8.07), 4.64 (2.13–10.12) and 2.28 (1.01–5.16) for poor glucose control only; poor glucose & blood pressure control; poor glucose & lipid control; and poor glucose, blood pressure & lipid control, respectively. Correspondingly for diabetic macular edema, they were 3.19 (1.55–6.59); 3.60 (1.58–8.22); 2.76 (1.18–6.44); and 3.01 (1.18–7.67), respectively. Odds were not significantly increased for other indicators.

Compared to individual indicators of poor diabetes control, risk of diabetic retinopathy and diabetic macular edema increased three to fourfold with a combination of these indicators. Targeting combined diabetes control indicators is important to reduce risk of diabetic retinopathy/diabetic macular edema.

Partial Text

Diabetic retinopathy (DR) is a common microvascular complication of diabetes that affects about a third of all people with diabetes[1] and, together with diabetic macular edema (DME), which can occur at any stage of DR,[2] is accountable for 4.8% of the 37 million cases of blindness worldwide.[3] DR can significantly affect quality of life, particularly at the vision-threatening stages (i.e. severe non-proliferative DR, proliferative DR, and clinically significant DME),[4] with substantial public health implications in terms of resources allocated to screening and management.[5]

Of the 613 patients (mean±SD age 66.0±10.5 [range 26–89] years and 57% male), 372 (60.1%) had any DR and 181 (30.5%) any DME. Of those with DR, 213 (57.3%) and 159 (42.7%) had mild/moderate NPDR and severe NPDR/PDR, respectively. Compared to patients without DR, those with the condition were more likely to be male, younger, have longer duration of diabetes, use insulin, have at least one other diabetes complication, and at least one comorbidity (all p<0.05, Table 1). Those with DR (Table 1) and DME (S1 Table) were more likely to have poor glucose control, poor BP control and poor lipid control, individually as well as in combination (all p<0.05) compared to those without these conditions. A total of 542 (88.4%) patients had complete data for all three indicators of diabetes control. Of these, less than one fifth (n = 99; 18.3) had good control of all three indicators (HbA1c<7%, SBP/DBP<130/80 and TC:HDL<4.0, Fig 1). Our study found that less than one in five persons attending a tertiary eye care facility achieved the combination of optimal glucose control, BP control and lipid control. In contrast, nearly one in ten participants had poor control of all three indicators of diabetes control, and nearly two thirds had poor glucose control, suggesting that diabetes control in adults with type 2 diabetes in Australia remains extremely poor, consistent with other studies.[22, 23] Compared to those with good control of all three indicators, persons with suboptimal BP control and glucose control; and those with suboptimal lipid control and glucose control were nearly four to five times more likely to have DR, respectively, while those with poor glucose control only were 2.5 times more likely. Similarly, the odds of having DME were significantly higher in those with poor glucose control and poor lipid control compared to those with poor glucose control alone. Our study suggests that while poor BP control or poor lipid control on their own do not greatly increase risk of DR, they amplify the risk when combined with poor glucose control. These findings support the current guidelines that suggest a multifactorial systemic management plan for people with diabetes is needed to manage DR and DME.   Source: http://doi.org/10.1371/journal.pone.0180252

 

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