Association between serum lipoprotein (a) level and progression of non-proliferative diabetic retinopathy in Type 2 diabetes

Lipoprotein (a) as a predictor of diabetic retinopathy in patients with type 2 diabetes: A systematic review

BACKGROUND

Lipoprotein a (LP(a)), an LDL-like lipoprotein, known as a risk factor for cardiovascular diseases, has a controversial association with diabetic retinopathy in patients with type 2 diabetes-the current systematic review aimed to critically assess the association between LP(a) and diabetic retinopathy.

METHODS

A systematic review of relevant studies was conducted after a thorough search in PubMed, Scopus, and Google Scholar electronic databases. We used English observational, case-control, and prospective cohort studies published up to August 2022, including type 2 diabetic patients as the population, diabetic retinopathy as the outcome, and LP(a) as the intervention.

RESULT

17 relevant studies, including 4688 patients with diabetes, were included in this systematic review. While in 13 studies, Lipoprotein(a) was recognized as a risk factor for diabetic retinopathy, only three studies reported no evidence of a relationship between the two. Also, another study showed a mixed outcome of the relationship between LP(a) and diabetic retinopathy.

CONCLUSION

High serum lipoprotein(a) in patients with type 2 diabetes is considered a risk factor for diabetic retinopathy. However, further large-scaled cohort studies are still required to validate this finding.

Direct medical cost and medications for patient of diabetes retinopathy in Beijing, China, 2016 to 2018

AIMS

Medications and costs of drug for diabetic retinopathy in outpatient in China have not been evaluated. The purpose of this study was to evaluate the hypoglycemic drugs and medical costs of diabetic retinopathy patients in the Beijing medical insurance system, analyze the characteristics of outpatient treatment, and investigate the changes in the quantity and cost of hypoglycemic drugs from 2016 to 2018 METHODS: This is a retrospective observational study, including diabetic patients with outpatient records in Beijing medical insurance from 2016 to 2018. Data on oral hypoglycemic drugs , insulin and non-hypoglycemic drugs, complications, treatment strategies, and annual medical costs were recorded Results: A total of 2,853,036 diabetic patients in Beijing medical insurance were enrolled in this study. 4.19%-4.67% of patients were diagnosed with retinopathy. Patients with retinopathy have more diabetic complications (1.65±0.71 vs 0.18±0.44. pp<.0001),and use more drugs (5.11±2.60 vs 3.85±2.34, pp <.0001), the annual total drug cost is also higher (¥ 13836±11244 vs ¥ 10030±9375, pp <.0001). The numbers of medication in retinopathy patients increased(5.11±2.60 vs 4.95±2.57, pp <.0001), and the annual total drug cost (¥13836±11244 vs ¥15642±13344, pp <.0001)decreased in 2018 compared with 2016.

CONCLUSIONS

Patients with retinopathy were associated with more complications. Compared with patients without retinopathy, the number of medications and total medical costs were significantly increased. From 2016 to 2018, there was an increase in the number of medication treatments for patients with retinopathy, but a decrease in cost.

LPA Genotypes and Haplotypes Are Associated with Lipoprotein(a) Levels but Not Arterial Wall Properties in Stable Post-Coronary Event Patients with Very High Lipoprotein(a) Levels

Lipoprotein(a) [Lp(a)] levels are an independent risk factor for coronary artery disease (CAD). Two single-nucleotide polymorphisms (rs10455872, rs3798220) and number of KIV-2 repeats in the gene encoding Lp(a) (LPA) are associated with Lp(a) and CAD. Our aim was to investigate whether in patients with stable CAD and high Lp(a) levels these genetic variants are associated with increased Lp(a) and arterial wall properties. Blood samples underwent biochemical and genetic analyses. Ultrasound measurements for the functional and morphological properties of arterial wall were performed. Genotypes of rs10455872 and haplotypes AT and GT showed significant association with Lp(a) levels. Patients with GG showed significantly higher Lp(a) levels compared with those with AG genotype (2180 vs. 1391 mg/L, p = 0.045). Patients with no AT haplotype had significantly higher Lp(a) compared to carriers of one AT haplotype (2158 vs. 1478 mg/L, p = 0.023) or two AT haplotypes (2158 vs. 1487 mg/L, p = 0.044). There were no significant associations with the properties of the arterial wall. Lp(a) levels significantly correlated also with number of KIV-2 repeats (r = -0.601; p < 0.0001). In our patients, these two LPA polymorphisms and number of KIV-2 repeats are associated with Lp(a), but not arterial wall properties.

General health of patients with diabetic macular edema-The LIPSIA study

PURPOSE

Cardiovascular risk factors such as hypertension or dyslipidemia can influence the incidence and progression of diabetic retinopathy (DR) and diabetic macular edema (DME). The aim of this study is to describe the comorbidities in patients with DME.

METHODS

Prospective, monocentric observational study. Patients presenting for the treatment of DME received laboratory and clinical examinations including 24-hour blood pressure measurement.

RESULTS

Seventy-five consecutive patients were included in the study. The mean age was 61.0 ± 14.5 years, and 83% had type 2 diabetes. The mean body mass index (BMI) was 32.8 ± 6.0 kg/m2. Overweight (BMI ≥ 25 kg/m2) was present in 92% of all patients. HbA1c values were > 7.0% in 57%. Although 87% of the patients already received antihypertensive therapy, the blood pressure (BP) of 82% was still above the recommended target values of systolic < 140 mmHg and diastolic < 80 mmHg. An insufficient nocturnal fall of the systolic BP (< 10%, non-dipping or reverse dipping) was observed in 62%. In 83% of the patients the glomerular filtration rate was ≤ 90 ml/min/1.73m2. Despite 65% of the cohort already receiving lipid-lowering therapy, LDL cholesterol was above the target value of 1.4 mmol/l in 93%. All patients had at least one cardiovascular risk factor in addition to diabetes (overweight, hypertension, insufficient nocturnal BP fall, dyslipidemia, or renal dysfunction) and 86% had ≥ 3 risk factors.

CONCLUSION

DME patients are characterized by highly prevalent cardiovascular risk factors that are poorly controlled. These comorbidities reduce the prognosis and negatively influence existing DR and DME. The data reveal an important opportunity for improving patient care by interaction of the ophthalmologist with the general practitioner and internal specialists for the detection and treatment of these conditions.

Correlation between Imaging Morphological Findings and Laboratory Biomarkers in Patients with Diabetic Macular Edema

PURPOSE

To investigate the potential association between peripheral blood biomarkers and morphological characteristics of retinal imaging in patients with diabetic macular edema (DME).

METHODS

Participants in this cross-sectional study were 36 consecutive patients (36 eyes) with treatment-naïve DME, who underwent spectral domain-optical coherence tomography (SD-OCT), fundus photography, and fundus fluorescein angiography (FFA). In addition, peripheral blood samples were taken to evaluate full blood count and biochemical parameters. Correlation between imaging characteristics and laboratory parameters was examined.

RESULTS

Eyes with central subfield thickness greater than 405 μm presented significantly higher neutrophils/lymphocytes (p = 0.043) and higher lipoprotein (a) compared to eyes with CST < 405 μm (p = 0.003). Presence of hyperreflective foci on SD-OCT was associated with significantly higher white blood cell count (p = 0.028). Ellipsoid zone disruption was associated with significantly lower hematocrit (p = 0.012), hemoglobin (p = 0.009), and red blood cell count (p = 0.026), as well as with higher lipoprotein (a) (p = 0.015). Macular ischemia on FFA was associated with significantly higher monocytes (p = 0.027) and monocytes/HDL (p = 0.019). No significant associations were found between laboratory parameters and subretinal fluid, intraretinal fluid, exudates, cysts, disorganization of inner retinal layers, epiretinal membrane, and external limiting membrane condition.

CONCLUSION

Specific imaging morphological characteristics were found to be associated with laboratory parameters in patients with DME. These findings may shed light on the pathophysiology of DME and its correlation with the development of specific clinical signs.

Lipoprotein(a) and Apolipoproteins as Predictors for Diabetic Retinopathy and Its Severity in Adults With Type 2 Diabetes: A Case-Cohort Study

OBJECTIVES

Our aim in this study was to assess the relationship between serum lipoprotein(a) [Lp(a)] and apolipoproteins and the risk of developing diabetic retinopathy (DR).

METHODS

One thousand fifty-seven patients with type 2 diabetes were divided into 2 main groups and followed for 5 years: 637 patients without DR and 420 patients with DR. A group of patients with DR were then divided into 2 subgroups: 162 patients with nonproliferative DR (NPDR) and 163 patients with proliferative DR (PDR). The association between serum Lp(a) and apolipoproteins with NPDR and PDR was assessed using univariate and multivariate regression analyses. Receiver-operating characteristic curve analysis was performed based on the new cutoff values.

RESULTS

There was a positive relationship between Lp(a) and the presence of DR as well as a negative correlation between ApoA and DR (p<0.001 and p=0.03, respectively). We also found a positive association between ApoB and the severity of DR (p=0.008). ApoA1 had an area under the curve of 55.0% for the prediction of DR. The calculated cutoff values of ApoB/ApoA1 ratio (0.58 g/L) and ApoB (77.5 g/L) in detection of DR were lower than their standard cutoff values of 0.8 and 90 g/L, respectively. Also, the sensitivity of new cutoff values for ApoB and ApoB/ApoA1 ratio was higher than the standard value, but the specificity of the standard cutoff values for both was higher than our new cutoff value.

CONCLUSIONS

Serum Lp(a) and ApoA1 levels were independently associated with DR, and serum ApoB correlated with severity of DR. These measurements can be used for assessment and early treatment of this vision-threatening complication of diabetes.

Systemic Factors Related to Intraocular Levels of Interleukin-6 and Vascular Endothelial Growth Factor in Diabetic Retinopathy

This study is for identifying systemic factors correlating with intraocular levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in diabetic retinopathy. Forty-two consecutive patients undergoing pars plana vitrectomy (PPV) for PDR were included in this cross-sectional study. The aqueous humor was sampled just prior to PPV for assay of IL-6 and VEGF. One day before PPV, patient characteristics were recorded and a number of systemic markers were amassed, including fasting and postprandial glucose, homeostasis model assessment- (HOMA-) IR, HOMA-beta, C-peptide, insulin, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein- (Apo-) A, Apo-B, and lipoprotein A (Lp-A). Relationships between systemic determinants and intraocular cytokine levels were analyzed by regression analysis. Mean levels of IL-6 and VEGF were 15.3 pg/mL (range, 2.4–10124.5 pg/mL) and 21.1 pg/mL (range, 3.2–766.1 pg/mL), respectively. After adjustment for age, gender, duration of diabetes, and BMI, multivariate analysis showed significant association of smoking (p=0.002) and HOMA-IR (p=0.003) with intraocular IL-6 levels, while intraocular VEGF and systemic Lp-A levels correlated significantly (p=0.032). Insulin resistance and smoking status impacted intraocular levels of IL-6, while intraocular VEGF levels were influenced by Lp-A. An appreciation for the relationship between systemic factors and intraocular cytokines may help elucidate the complex pathophysiology of diabetic retinopathy.

Association Between Serum Lipoprotein(a) and Diabetic Retinopathy in Han Chinese Patients With Type 2 Diabetes

CONTEXT

Contrasting observations have been made on the relationship between lipoprotein(a) [Lp(a)] concentration and diabetic retinopathy (DR) in patients with type 2 diabetes (T2D).

OBJECTIVE

To measure serum Lp(a) concentrations in patients with T2D to investigate whether Lp(a) affects risk for DR.

DESIGN AND PATIENTS

Serum Lp(a) was determined in 377 Han Chinese patients with T2D. Demographic and clinical information, including presence of DR and vision-threatening DR (VTDR), were collected on admission. The relationship between serum Lp(a) and DR or VTDR was evaluated using univariate and multivariate regression analyses.

RESULTS

Patients with DR or VTDR had significantly higher serum Lp(a) concentrations on admission (P < 0.001). The distribution across Lp(a) quartiles ranged from 11.7% (DR) and 4.3% (VTDR) in the first quartile to 47.9% (DR) and 19.1% (VTDR) in the fourth quartile (P for trend < 0.001). Multivariate logistic regression analysis adjusted for common DR and VTDR risk factors showed that the third and fourth Lp(a) quartiles were significantly associated with DR and VTDR compared with the first Lp(a) quartile (P < 0.001). The patient group with highest concentrations of both Lp(a) (fourth quartile) and hemoglobin A1c (≥7%) had an odds ratio for DR of 5.15 [95% confidence interval (CI), 2.78 to 9.55; P < 0.001] and for VTDR of 5.32 (95% CI, 2.92 to 10.15; P < 0.001) compared with patients with lower concentrations of both factors.

CONCLUSIONS

Lp(a) concentration was independently associated with DR in patients with T2D. More frequent retinal examinations should be recommended for patients with T2D and high Lp(a) concentrations.

Clinical Course and Risk Factors of Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus in Korea

BACKGROUND

We investigated clinical course and risk factors for diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 759 patients with T2DM without DR were included from January 2001 to December 2004. Retinopathy evaluation was performed at least annually by ophthalmologists. The severity of the DR was classified into five categories according to the International Clinical Diabetic Retinopathy Severity Scales.

RESULTS

Of the 759 patients, 523 patients (68.9%) completed the follow-up evaluation. During the follow-up period, 235 patients (44.9%) developed DR, and 32 patients (13.6%) progressed to severe nonproliferative DR (NPDR) or proliferative DR (PDR). The mean duration of diabetes at the first diagnosis of mild NPDR, moderate NPDR, and severe NPDR or PDR were 14.8, 16.7, and 17.3 years, respectively. After adjusting multiple confounding factors, the significant risk factors for the incidence of DR risk in patients with T2DM were old age, longer duration of diabetes, higher mean glycosylated hemoglobin (HbA1c), and albuminuria. Even in the patients who had been diagnosed with diabetes for longer than 10 years at baseline, a decrease in HbA1c led to a significant reduction in the risk of developing DR (hazard ratio, 0.73 per 1% HbA1c decrement; 95% confidence interval, 0.58 to 0.91; P=0.005).

CONCLUSION

This prospective cohort study demonstrates that glycemic control, diabetes duration, age, and albuminuria are important risk factors for the development of DR. More aggressive retinal screening for T2DM patients diagnosed with DR should be required in order to not miss rapid progression of DR.

Lipoprotein(a) predicts the development of diabetic retinopathy in people with type 2 diabetes mellitus

BACKGROUND

Lipoprotein(a) [Lp(a)] has mainly been considered to be a predictor of the incidence of cardiovascular disease. In addition, previous studies have shown potential linkage between Lp(a) and diabetic microvascular complications.

OBJECTIVES

We investigated the incidence and risk factors for the development of diabetic retinopathy (DR) in patients with type 2 diabetes.

METHODS

A total of 787 patients with type 2 diabetes without DR were consecutively enrolled and followed up prospectively. Retinopathy evaluation was annually performed by ophthalmologists. The main outcome was new onset of DR.

RESULTS

The median follow-up time was 11.1 years. Patients in the DR group had a longer duration of diabetes (P < .001), higher baseline HbA1c (P < .001), higher albuminuria level (P = .033), and higher level of Lp(a) (P = .005). After adjusting for sex, age, diabetes duration, presence of hypertension, renal function, LDL cholesterol, mean HbA1c, and medications, the development of DR was significantly associated with the serum Lp(a) level (HR 1.57, 95% confidence interval [1.11-2.24]; P = .012, comparing the 4th vs 1st quartile of Lp(a)). The patient group with the highest quartile range of Lp(a) and mean HbA1c levels ≥7.0% had an HR of 5.09 (95% confidence interval [2.63-9.84]; P < .001) for developing DR compared with patients with lower levels of both factors.

CONCLUSIONS

In this prospective cohort study, we demonstrated that the DR was independently associated with the serum Lp(a) level in patients with type 2 diabetes.

Lipoprotein(a) and Arterial Stiffness Parameters

BACKGROUND

Circulating lipoprotein(a) [Lp(a)] and arterial stiffness are markers associated with the atherosclerotic processes. With regard to cardiovascular outcomes, the relationship between Lp(a) and arterial stiffness has not been sufficiently summarized. The present review focuses on the existing association between Lp(a) and arterial stiffness parameters.

SUMMARY

This review included human clinical studies that were published between 1980 and 2015. The metrics of arterial stiffness parameters, 'pulse wave velocity' (PWV) and 'cardio-ankle vascular index' (CAVI), were used for this search, which yielded only 4 cross-sectional studies on this topic. Of these 4 studies, 3 reports were based on the use of PWV, while 1 study was based on the use of CAVI. Three studies (including the study using CAVI) reported that high Lp(a) levels were positively associated with arterial stiffness.

CONCLUSION

The present review indicates a positive association between Lp(a) and arterial stiffness, as assessed by PWV and CAVI. To definitively establish these findings, there is a need for further prospective outcome studies that simultaneously measure Lp(a) and the oxidative form of Lp(a) (as a pathological marker) as well as PWV and CAVI.

Lipoprotein (a): gene genie

PURPOSE OF REVIEW

Despite being both the longest known and the most prevalent genetic risk marker for atherosclerotic cardiovascular disease (CVD), little progress has been made in agreeing a role for lipoprotein (a) [Lp(a)] in clinical practice and developing therapies with specific Lp(a)-lowering activity. We review barriers to progress, and discuss areas of controversy which are important to future research.

RECENT FINDINGS

Epidemiological and genetic studies have supported a causal role for Lp(a) in accelerated atherosclerosis, independent of other risk factors. Progress continues to be made in the understanding of Lp(a) metabolism, and Lp(a) levels, rather than apolipoprotein (a) isoform size, have been shown to be more closely related to CVD risk. Selective Lp(a) apheresis has offered some evidence that Lp(a)-lowering can improve cardiovascular end-points.

SUMMARY

We have acquired a great deal of knowledge about Lp(a), but this has not yet led to reductions in CVD. This is at least partially due to disagreement over Lp(a) measurement methodologies, its physiological role and the importance of the elevations seen in renal diseases, diabetes mellitus and familial hypercholesterolaemia. Renewed focus is required to bring assays into clinical practice to accompany new classes of therapeutic agents with Lp(a)-lowering effects.

Epidemiological issues in diabetic retinopathy

There is currently an epidemic of diabetes in the world, principally type 2 diabetes that is linked to changing lifestyle, obesity, and increasing age of the population. Latest estimates from the International Diabetes Federation (IDF) forecasts a rise from 366 million people worldwide to 552 million by 2030. Type 1 diabetes is more common in the Northern hemisphere with the highest rates in Finland and there is evidence of a rise in some central European countries, particularly in the younger children under 5 years of age. Modifiable risk factors for progression of diabetic retinopathy (DR) are blood glucose, blood pressure, serum lipids, and smoking. Nonmodifiable risk factors are duration, age, genetic predisposition, and ethnicity. Other risk factors are pregnancy, microaneurysm count in an eye, microaneurysm formation rate, and the presence of any DR in the second eye. DR, macular edema (ME), and proliferative DR (PDR) develop with increased duration of diabetes and the rates are dependent on the above risk factors. In one study of type 1 diabetes, the median individual risk for the development of early retinal changes was 9.1 years of diabetes duration. Another study reported the 25 year incidence of proliferative retinopathy among population-based cohort of type 1 patients with diabetes was 42.9%. In recent years, people with diabetes have lower rates of progression than historically to PDR and severe visual loss, which may reflect better control of glucose, blood pressure, and serum lipids, and earlier diagnosis.

Serum lipoprotein(a) levels are greater in female than male patients with type-2 diabetes

Women with diabetes are faced with a higher risk of dyslipidemia and cardiovascular disorders than men with diabetes. We aimed to study the role of gender and menopausal status in serum Lp(a) levels in patients with type 2 diabetes. We quantified serum Lp(a) levels in a group of 477 patients with type 2 diabetes (men, premenopausal and postmenopausal women with diabetes), as well as in 105 controls. We stratified the patients into two groups of low Lp(a) levels (Lp(a) <35 mg/dl) and elevated Lp(a) levels (Lp(a) >35 mg/dl). Patients with diabetes had higher serum Lp(a) levels than the controls. Serum Lp(a) levels was significantly higher in women with diabetes than men with diabetes. Lp(a) levels did not differ between male and females in the control group. Premenopausal and postmenopausal women with diabetes did not differ significantly in serum Lp(a) levels. The odds ratio of having a serum Lp(a) level higher than 35 was 5.85 in premenopausal women with diabetes, 5.08 in postmenopausal women with diabetes, 2.41 in men with diabetes and 1.9 in the women in the control group compared to the men in the control group, after adjustment for age and BMI. This observational study clearly indicated that serum Lp(a) levels were significantly higher in women and men with diabetes. The increase in women was independent of menopause. The level of serum Lp(a) had no correlation with lipid parameters in men or women.