Year : 2016 | Volume
: 29 | Issue : 3 | Page : 593--596
Study of relation between serum lipids and loss of vision in patients with diabetic retinopathy
Hoda M Kamel Elsobky1, Nermeen M Badawi1, Ahmed A El-Hagaa1, Walid E Nasef2,
1 Department of Ophthalmology, Faculty of Medicine, Menoufia University, Shibin Elkom, Egypt
2 Department of Ophthalmology, Faculty of Medicine, Tanta University, Gharbia Governorate, Egypt
Walid E Nasef
Department of Ophthalmology, Faculty of Medicine, Tanta University, Gharbia Governorate, 31511
The aim of this study was to evaluate the association of serum lipids with vision loss in diabetic retinopathy (DR) patients and the effect of lipid-lowering agents.
Elevated serum lipids such as total cholesterol and triglycerides lead to vision deterioration through affection of retina in diabetic patients.
Patients and methods
Forty type 2 diabetic patients were evaluated for serum lipids, diabetic retinopathy (DR) and macular oedema from January 2013 to September 2013 in Menoufia University Hospital, Menoufia, Egypt. Antilipid therapy was administered to hyperlipidaemic patients with DR or macular oedema for 9 months and re-evaluated.
Of the 40 diabetic patients, 65% were male and 35% were female, and the mean age was 50.5 years (range = 20-80 years). An overall 75% of patients had DR and 25% of patients did not have DR. Various grades of clinically significant macular oedema (CSME) were detected in 42.5% of diabetic patients. Duration of diabetes ranged from 5 to 25 years. Dyslipidaemia was found in 70% of DR patients. Of the 25 dyslipidaemic patients, 12 patients (48%) had CSME. Total cholesterol, low-density lipoprotein, very-low-density lipoprotein and triglyceride level were elevated in DR and CSME. Hard exudate was present in 70% of DR patients with total cholesterol level above 230 mg/dl, and was present in 80% of DR patients with the ratio of total cholesterol level to high-density lipoprotein above 4.5. Retinal hard exudate decreased after antilipid therapy.
Dyslipidaemia is associated with an increased risk of development and progression of retinopathy and maculopathy in diabetic patients.
|How to cite this article:|
Kamel Elsobky HM, Badawi NM, El-Hagaa AA, Nasef WE. Study of relation between serum lipids and loss of vision in patients with diabetic retinopathy.Menoufia Med J 2016;29:593-596
|How to cite this URL:|
Kamel Elsobky HM, Badawi NM, El-Hagaa AA, Nasef WE. Study of relation between serum lipids and loss of vision in patients with diabetic retinopathy. Menoufia Med J [serial online] 2016 [cited 2020 Jul 6 ];29:593-596
Available from: http://www.mmj.eg.net/text.asp?2016/29/3/593/198721
Diabetic patients with retinopathy showed significantly high serum cholesterol levels compared with diabetic patients without retinopathy  , and it is the principle cause of vision impairment in the world  . The risk factors for diabetic retinopathy (DR) are degree of glycaemic and blood pressure control, duration of diabetes, presence of nephropathy and raised serum lipids. Elevated lipid concentrations may be an additional risk factor for diabetic macular oedema (DME), particularly the deposition of hard exudates (HEs) in the retina  .
As the density of these HEs increases, they tend to migrate towards the foveal centre where their deposition predisposes to the development of subfoveal fibrosis leading to irreversible visual loss  .
The vast majority of patients who develop DR have no symptoms until the very late stages by which time it may be too late for effective treatment  .
We performed a retrospective study to evaluate the effect of dyslipidaemia on the progression and development of DR and clinically significant macular oedema (CSME). The purpose of this study was to evaluate the outcome of antilipid therapy on HE at Menoufiya University Hospital, Menoufiya, Egypt. The aim of this work was to assess and evaluate dyslipidaemic effect on the retina and thus on vision, as well as antilipid therapy effect on HE.
Patients and methods
This retrospective study was conducted in the Ophthalmology Department in Menoufiya University Hospital, Menoufiya, Egypt, from 1 January 2013 to 30 September 2013.
A total number of 40 patients with more than 5 years of diagnosed diabetes type 2 and between 20 and 80 years of age were included in the study. Duration of diabetes ranged from 5 to 25 years. There were 26 male and 14 female patients. Patients with history less than 5 years of diagnosed diabetes, ocular surgery less than 6 months, those with accelerated hypertension, active ocular infection, coexisting ocular disorders such as uveitis, opaque or hazy media, retinal disorders such as retinal vein or artery occlusions or retinitis pigmentosa, vitreoretinal degenerations, dystrophies, high myopia, glaucoma and cataract were excluded from the study.
Of the 40 patients included in the study, 30 (75%) had DR and 10 (25%) did not have DR. Various grades of CSME were detected in 17 patients (42.5%).
Patients were divided into four groups as follows.
Group 1 included patients with no DR (the control group); group 2 included patients with mild-to-moderate nonproliferative DR with or without HEs; group 3 included patients with severe nonproliferative DR with small HEs; and group 4 included patients with proliferative DR with massive HEs.
All patients were subjected to the following:
Full history taking: age of the patient, type of diabetes, duration of diabetes, mode of diabetic control, family history of diabetes mellitus and history of known ocular or medical diseasesClinical examination, including assessment of visual acuity, refraction, tonometry using applanation tonometer, complete ophthalmological examination including slit-lamp biomicroscopy for anterior segment examination and using 78-D lens with it or indirect ophthalmoscope with 20-D lens for fundus examinations and best-corrected visual acuity using illuminated Landolt chartInvestigations: Ocular: fundus fluorescein angiography and optical coherent tomography Systemic: lipid profile measurements using fasting samples, fasting and postprandial blood sugar and haemoglobin A1c.
Serum lipid measurements were carried out using fasting samples. For the purpose of analysis, dyslipidaemia was defined as serum total cholesterol greater than 160 mg/dl, triglyceride levels greater than 150 mg/dl, low-density lipoprotein (LDL) levels greater than 100 mg/dl, and high-density lipoprotein (HDL) less than 40 mg/dl for men and less than 50 mg/dl for women  .
Patients were given antilipidaemic therapy according to the type of lipid elevated by medical specialist as follows. Simvastatin 20 mg tablet was given daily after dinner for 2 weeks to patients with high total cholesterol or high cholesterol components [LDL and very-low-density lipoprotein (VLDL)]. Ezetimibe 10 mg once daily may be added to simvastatins to inhibit cholesterol absorption in some resistant cases.
Fenofibrate 300 mg tablet (lipase stimulant drug) was given once daily with or after meal for 3 weeks to patients with high triglyceride levels. Patients with high total cholesterol or its components (LDL and VLDL) together with triglycerides were given simvastatin 20 mg tablet daily after dinner with fenofibrate 300 mg tablet once daily with or after meal for 1 month. All doses were repeated until normal levels were gained. Ophthalmological examinations and follow-up every 45 days were carried out.
After 9 months, the investigations were repeated again to see the effect of treatment.
Between January 2013 to September 2013, 40 diabetic patients underwent this study, of whom 26 (65%) were male and 14 (35%) were female, and the mean age was 50.5 years (range = 20-80 years). Duration of diabetes ranged from 5 to 25 years. Thirty (75%) patients had DR and 10 (25%) patients did not have DR. Various grades of CSME were detected in 12 diabetic patients (42.5%).
Prevalence of DR is significantly increased with increasing age (P < 0.05). Various stages of CSME were significantly increased with increasing age (P < 0.05). Prevalence of DR is significantly increased with increased duration of diabetes. Various stages of CSME were significantly increased with increased duration of diabetes (P < 0.05).
No significant relationship between sex and various stages of DR was found. Moreover, there was no significant relationship between sex and CSME (P > 0.05). Dyslipidaemia was found in 25 (62.5%) diabetic patients. Dyslipidaemia was found in 21 (70%) DR patients.
Twelve patients (48%) out of the 25 dyslipidaemic patients had CSME.
Serum lipid profile, including total cholesterol, LDL, VLDL and triglyceride level were elevated in DR and CSME.
The incidence of patients with elevated total cholesterol and triglycerides was 33% of all DR patients. The incidence of patients with elevated LDL and triglycerides was 23.5% of all DR patients. The incidence of patients with elevated LDL and VLDL was 20% of all DR patients. An overall 23.5% of all DR patients had normal lipid profile.
The percentage of patients with elevated total cholesterol and triglycerides was 30% of all CSME patients. The percentage of patients with elevated LDL and triglycerides was 23.5% of all CSME patients. The percentage of patients with elevated LDL and VLDL was 18% of all CSME patients. An overall 29% of all CSME patients had normal lipid profile.
HE was present in 21 (70%) DR patients with total cholesterol level above 230 mg/dl. In addition, HE was present in 80% of DR patients with the ratio of total cholesterol level to HDL above 4.5.
Retinal exudate decreased in patients who had exudative DR and took antilipid therapy regularly by about 60% in all DR patients.
Mean visual acuity was 6/12 in group 1 (the control group), 6/18 in group 2, 6/36 in group 3 and below 6/60 in group 4.
Mean visual acuity improved one to two lines on Landolt chart to be 6/12 in group 2, 6/18 in group 3 and 6/60 in group 4.
It is observed that as the duration of diabetes increases, the chances of having DR and CSME also increase. Various studies have shown an association of dyslipidaemia with macrovascular complications of diabetes (e.g. coronary artery disease), but few have studied the association of serum lipids with microvascular complications such as DR and the available results are conflicting , .
Early Treatment Diabetic Retinopathy Study (ETDRS) and Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) showed a stronger evidence for the role of serum lipids in exudative maculopathy. In the ETDRS, it was also reported that higher baseline total and LDL-cholesterol levels increased the risk for retinal exudation by two-fold. Dornan et al.  found that there is an association between total serum cholesterol and DR.
This study was conducted on 40 patients with type 2 diabetes who came to Menoufiya University Hospital for the evaluation and management of DR from January 2013 to September 2013. In this study, we found a significant association between dyslipidaemia and DR (70%), as well as a significant association between dyslipidaemia and CSME (48%).
In our study, we found that total serum cholesterol level is directly associated with the severity of retinal HEs in patients with DR and dyslipidaemia. These results were nearly similar to the results gained by Rema et al.  , who found that individuals with elevated total serum cholesterol, LDL-cholesterol, or triglyceride levels are more likely to have or develop retinal HEs, which can be associated with risk for vision loss, independent of the extent of macular oedema. Patients with a total cholesterol/HDL-cholesterol ratio of 4.5 or greater were almost twice as likely to have retinal HEs compared with those with a ratio less than 4.5. Patients with a higher quartile of total cholesterol or LDL-cholesterol levels were 5-6 times more likely to have retinal HEs than those with lowest quartiles. Moreover, patients with elevated total cholesterol (240 mg/dl or 6.21 mmol/l) were twice as likely to have retinal HEs at baseline (odds ratio = 2.00; 99% confidence interval = 1.35-2.95).
Similar results were found when comparing the elevated LDL levels (160 mg/dl or 1.14 mmol/l) with the lowest level of LDL (130 mg/dl or 3.37 mmol/l) and the odds ratio was 1.97 (99% confidence interval = 1.3-2.96).
Patients with elevated cholesterol and triglyceride levels were 50% more likely to develop retinal HEs. Elevated serum cholesterol at baseline also increased the risk for visual loss by 50% compared with lower serum cholesterol levels. Independent of the accompanying macular oedema, the severity of retinal HEs at baseline was associated with decreased visual acuity  . Lowering serum lipids has shown a benefit on both proliferative disease and maculopathy besides their lipid-lowering effect. Independent of accompanying macular oedema, the severity of retinal HEs at baseline was associated with decreased visual acuity. Similar results were seen in ETDRS and WESDR studies , .
Actions to Control Cardiovascular Risk in Diabetes (ACCORD)  is a randomized controlled clinical trial with three components, determining the effects of lowering blood glucose, lowering blood pressure, and using fibrates to lower serum triglycerides and raise serum HDL-cholesterol levels (on a background of statin treatment) on cardiovascular disease in patients with type 2 diabetes, and a subset of participants with this study will be evaluated with a standardized protocol for comprehensive eye examinations and fundus photography consisting of the seven stereoscopic fields. An important association of DR with total cholesterol and serum triglycerides was showed  .
High serum triglycerides have also been shown to be associated with the increased risk of the development and progression of retinopathy by Hadjadj et al.  .
There has been increasing interest in the link between serum lipids and maculopathy in view of the evolving medical treatment. In type 2 diabetic patients, DME showed an association with increased LDL levels  . Elevated serum cholesterol at baseline also increased the risk for visual loss by 50% compared with lower serum cholesterol levels  .
This association was maintained even after adjusting for age, as age by itself is a significant risk factor for hyperlipidaemia. The other significant finding in type 2 diabetes was that DME also showed a strong correlation with high LDL levels in the same study  .
We also found that the risk for visual acuity loss was associated with both the presence and increasing severity of HE at baseline, adjusted for the presence and increasing severity of macular oedema.
This is in agreement with ETDRS  , which detected that in a period of 5 years of follow-up the intensive treatment of hyperglycaemia substantially reduces the DR development and progression. The investigators evaluated the correlation of serum lipids and the incidence of macular oedema and retinal HEs. Elevated LDL was associated with an increased risk for macular oedema. These findings were similar to those found in the ETDRS  .
DR is one of the most important causes of vision loss worldwide. Serum lipid levels have a significant effect on the severity of retinal HEs. As the density of these HEs increases, they tend to migrate towards the foveal centre where their deposition predisposes to subfoveal fibrosis. Lowering serum lipids has shown benefit on both proliferative DR and maculopathy.
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Conflicts of interest
There are no conflicts of interest.
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