Study of possible risk factors for severe retinopathy in non-insulin dependent diabetes

The association of smoking and risk of diabetic retinopathy in patients with type 1 and type 2 diabetes: a meta-analysis

PURPOSE

To clarify the relevance between smoking and diabetic retinopathy in patients with type 1 and type 2 diabetes mellitus.

METHODS

Published evidence were searched in MEDLINE and EMBASE from the databases began until Feb. 2017. Studies evaluating the association between smoking and diabetic retinopathy or evaluating the risk factors of diabetic retinopathy including smoking were included.

RESULTS

Totally 73 studies were identified, among which 19 studies included type 1 diabetes patients and 56 studies included type 2 diabetes patients. In type 1 diabetes, compare with non-smokers, the risk of diabetic retinopathy significantly increased in smokers (risk ratio (RR) = 1.23, 95% CI 1.14, 1.33, P < 0.001), and the risk of proliferative diabetic retinopathy also significantly increased in smokers (RR = 1.48, 95% CI 1.20, 1.81, P < 0.001). In type 2 diabetes, compare with non-smokers, the risk of diabetic retinopathy significantly decreased in smokers (RR = 0.92, 95% CI 0.86, 0.98, P = 0.02) and the risk of proliferative diabetic retinopathy also significantly decreased in smokers (RR = 0.68, 95% CI 0.61, 0.74, P < 0.001).

CONCLUSIONS

Compare with non-smokers, the risk of diabetic retinopathy significantly increased in smokers with type 1 diabetes while significantly decreased in smokers with type 2 diabetes. However, this result did not change the importance of smoking cessation for public health.

Incidence of and risk factors for diabetic retinopathy in diabetic clinic attenders

The incidence and risk factors for the development of diabetic retinopathy during a mean (SD) follow-up period of 4.6 (2.9) (range 1-12.4) years have been examined among 3424 patients (1878 males and 1546 females) with diabetes mellitus from three outpatient clinics at the University Hospital, Nottingham. The mean (SD) age of participants was 49.2 (17.9) years with a mean (SD) duration of diabetes of 7.3 (9.0) years at initial registration. Among the 3424 patients free of retinopathy at initial registration who attended the clinic at least twice in the period 1979-1992, the incidence of any retinopathy was 59.6 (57.8 male and 61.8 female) per 1000 person-years based on 15,571 person-years of follow-up. The incidence rate of retinopathy was 72% higher among insulin-treated than among non-insulin-treated noninsulin-dependent diabetes mellitus (NIDDM) clinic attenders. Using a Cox's Proportional Hazards Model for insulin-dependent diabetes (IDDM) and NIDDM (insulin and non-insulin-treated) diabetes separately, longer duration of diabetes, higher systolic blood pressure and poor metabolic control were significant independent predictors of retinopathy for all three groups. Never smoking was a significant independent predictor of retinopathy for the insulin-dependent diabetes groups. Lower body mass index, proteinuria and age were predictors of retinopathy only for non-insulin-treated NIDDM patients. Gender and creatinine had no significant independent association with retinopathy when other covariates were considered. These findings will help the identification of those patients at particular risk of retinopathy so that clinic time for screening of eyes can be appropriately focused.

Systemic considerations in the management of diabetic retinopathy

PURPOSE

To highlight the systemic factors which affect onset and/or progression of diabetic retinopathy (DR) and to emphasize the role and responsibilities of ophthalmologists and other eye care providers to ensure that appropriate systemic medical evaluation of the patient with diabetes is being pursued.

DESIGN

Literature review of publications relevant to diabetic retinopathy, blood glucose control, diabetes mellitus type, hypertension, renal disease, elevated serum lipids, exercise, pregnancy, anticoagulation, thrombolysis, smoking, anemia and antioxidant ingestion.

FINDINGS

Intensive blood glucose control and control of systemic hypertension reduce the risk of new onset DR and slow the progression of existing DR. Severe DR may be an indicator of renal disease while severe renal disease and its treatment can affect the progression of DR. Elevated serum lipids are associated with macular exudate and moderate visual loss. Certain types of excessive exercise in patients with advanced stages of retinopathy may aggravate vitreous hemorrhage. During pregnancy, DR should be monitored closely as transient progression of DR can occur. Therapeutic anticoagulation and thrombolysis are not contraindicated at any stage of DR. Anemia can result in progression of DR, smoking in general should be discouraged, and the role of antioxidant therapy requires further study.

CONCLUSIONS

Blindness from diabetic retinopathy is now largely preventable with timely detection and appropriate interventional therapy. Routine, repetitive, lifelong, expert clinical retinal examination is essential for the fundamental ophthalmic care of the patient with diabetes. However, diabetes mellitus is a systemic disease and thus optimal ophthalmic care must include diligent evaluation and treatment of concomitant systemic disorders that influence the development, progression and ultimate outcome of diabetic retinopathy. Optimization of these systemic considerations through an intensive, multi-disciplinary, healthcare team-based approach will maximize the ophthalmic and general health of these patients. Ophthalmologists and other eye care providers are critical members of this team with unique responsibilities to ensure that appropriate systemic medical evaluation is being pursued.

Dominant risk factors for retinopathy at clinical diagnosis in patients with type II diabetes mellitus

A study of 270 newly presenting, previously untreated, type II diabetic patents revealed that 38 patients (14%) had already developed diabetic retinopathy (DR). Among this group, 26 patients had lesions of background diabetic retinopathy and 12 patients already had maculopathy or preproliferative changes. The aim of this study was to determine the risk factors influencing susceptibility to retinopathy, and to provide an accurate predictive value for diabetic retinopathy from a detailed multiple regression analysis that involved 27 demographic variables and the metabolic and hormonal responses during a meal tolerance test (MTT) at presentation. Compared to the nonretinopaths, the retinopaths had higher fasting plasma glucose levels (FPG) (mean +/- SD) (13.9 +/- 3.1 versus 11.6 +/- 3.2 mmol/L, p < 0.001), lower body-mass index values (BMI) (26.1 +/- 3.8 versus 29.3 +/- 5.0 kg/m2, p < 0.001) and higher plasma urea concentrations (6.0 +/- 1.9 versus 5.3 +/- 1.2 mmol/L, p 0.05). In contrast, gender and levels of blood pressure and other lipid levels did not influence the prevalence of diabetic retinopathy. A multiple regression formula for the prediction of diabetic retinopathy was derived and then used to categorize patients into high-risk and low-risk groups. The retinopaths also had higher HbA1c (p < 0.001), higher plasma glucose are under curve (0-2 h, p < 0.001), lower plasma insulin area under curve (0-22 h, p < 0.001), lower C-peptide area under curve (0-2 h, p < 0.01). They were also leaner (p < 0.001) and older (p < 0.05). However, these variables did not feature significantly in the multiple regression formula. The retinopaths were found to have higher risk probability values (25.1 +/- 11.5 versus 13.1 +/- 10.4%, p < 0.001). In the high risk group, 81.6% of retinopaths were identified. In the low-risk group, 63.8% of nonretinopaths were found. The incidence of diabetic retinopathy in type II diabetic patients at clinical diagnosis was found to be highly related to the degree of hyperglycemia, body-mass index, and to a lesser extent, renal impairment.

Cigarette smoking and diabetes: an update

The article provides an overview of recent scientific information on the role of cigarette smoking in the prognosis of diabetes. Data sources included an English-language MEDLINE search for 1989 through 6/1993, supplemented by manual search of bibliographies of pertinent articles. Only studies of humans were considered. Cigarette smoking is related to the development and progression of diabetic nephropathy. Therefore, smoking status has to be taken into account in clinical studies on the course of nephropathy. The association between smoking and retinopathy is less consistent. Evidence is accumulating that cigarette smoking influences insulin action. Several large prospective cohort studies have shown that the relative risk for all-cause mortality is about twice as high for smoking compared to non-smoking diabetic patients. Strong associations are consistently found between cigarette-pack years and complications. It has been calculated that the theoretical benefit of stopping smoking is the most (cost-)effective risk factor intervention for diabetic patients. However, available programmes to help diabetic patients to stop smoking are unsuccessful.

Is there an ethnic difference in the effect of risk factors for diabetic retinopathy?

Mexican Americans have an increased prevalence and incidence of non-insulin-dependent diabetes mellitus (NIDDM). In addition, Mexican American diabetic subjects have an increased prevalence of retinopathy relative to Caucasian diabetic subjects. In Mexican American diabetic subjects, established risk factors may have a stronger effect on diabetic retinopathy, compared to Caucasian diabetic subjects. In this report, we compare the effect of established risk factors (age at examination, gender, age at diagnosis of diabetes, duration of diabetes, glycemia, type of therapy, systolic and diastolic blood pressure, and hypertension prevalence) between Caucasian diabetic subjects (n = 478), a low-risk population for NIDDM (Wisconsin Epidemiologic Study of Diabetic Retinopathy), and Mexican American diabetic subjects (n = 231), a high-risk population for NIDDM (San Antonio Heart Study). Retinopathy was classified into two categories (any or none) as assessed by seven standard stereoscopic retinal photographs read at the University of Wisconsin Reading Center. Mexican American diabetic subjects in Texas had an increased prevalence of any retinopathy (odds ratio = 1.71, 95% confidence interval: 1.25, 2.34), compared to Caucasian diabetic subjects in Wisconsin. Longer duration of diabetes, more severe glycemia, earlier age at diagnosis, and insulin therapy were associated with diabetic retinopathy in both Mexican Americans and Caucasians. Socioeconomic status was not associated with prevalence of retinopathy. Moreover, the effect of risk factors for retinopathy was similar in both ethnic groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The prevalence of diabetic retinopathy and maculopathy and their risk factors in the non-insulin-treated diabetic patients of an English town

A total population study of the ocular status of all known non-insulin-treated diabetic patients resident in the English town of Melton Mowbray has been conducted. The population prevalence of non-insulin-treated diabetes in the town was 6.7/1000. There were 215 patients in the target population, with 65% of the resident survivors participating in the study. Further data on ocular status were gathered from hospital records, bringing the total percentage for whom some information on ocular status was available to 74%. Corrected Snellen acuity was 6/12 or better in 76% of patients and the over-all prevalence rate for any diabetic retinopathy was 52%, for proliferative retinopathy was 4%, and for maculopathy requiring treatment was 10%. In a multivariate analysis, risk factors for retinopathy and/or maculopathy included longer diabetic duration, female sex, higher blood pressure, the use of anti-hypertensive drugs and cigarette smoking.

Putative risk factors associated with retinopathy in patients with diabetes diagnosed at or after 30 years of age

In a cross-sectional study of diabetic patients diagnosed at or after 30 years, and with different stages of retinopathy, factors such as duration of diabetes, treatment mode, metabolic control, blood pressure, and clinical signs of nephropathy were examined. The different stages of retinopathy used were absence of retinopathy, simplex, and severe retinopathy. Patients with simplex and severe retinopathy were older than those without retinopathy (p less than 0.001, and p less than 0.01, respectively). They also had a longer duration of diabetes (p less than 0.001), and were more often treated with insulin (p less than 0.001) and in larger doses (p less than 0.001). Their glycosylated haemoglobin levels were higher (p less than 0.01). Their systolic blood pressure was higher (p less than 0.01), but the diastolic blood pressure did not differ, and the number of patients treated for hypertension was similar in all groups. Albumin clearance was higher (p less than 0.01 and p less than 0.001), as were urinary albumin levels (p less than 0.001). The only variables that distinguished patients with simplex from those with severe retinopathy were albumin clearance (p less than 0.01) and urinary albumin levels (p less than 0.05).

Association of hypertension with blood viscosity in diabetes

Plasma and whole blood viscosity and its determinants were measured in 86 diabetic patients (29 hypertensive and 57 normotensive) and compared with 52 non-diabetic control subjects to assess whether hypertension has an additive and adverse effect on blood viscosity. Whole blood viscosity (corrected for haematocrit), at high and low shear rates (95 and 0.95 s-1), was significantly higher in both Type 1 (5.1 +/- 0.5 (+/- SD), 19.8 +/- 2.9) and Type 2 (5.2 +/- 0.3, 21.1 +/- 2.0) diabetic patients compared with control subjects (4.9 +/- 0.6, 17.4 +/- 2.6 mPa s, p less than 0.01). Corrected whole blood viscosity at high shear rate was significantly higher in hypertensive than in normotensive Type 2 diabetic patients (5.5 +/- 0.4 vs 5.2 +/- 0.3 mPa s, p less than 0.01). Plasma viscosity was significantly higher in diabetic patients compared with control subjects (1.4 +/- 0.1 vs 1.3 +/- 0.1 mPa s, p less than 0.01), but there was no difference between hypertensive and normotensive diabetic patients (1.4 +/- 0.1 vs 1.4 +/- 0.2 mPa s). Fibrinogen levels were similar in all the groups.

Relationship between retinopathy and glycaemic control in insulin-dependent and non-insulin-dependent diabetes

The possible relationship between antecedent diabetic control, as determined by serial glycosylated haemoglobin (HbA1) measurements, and diabetic retinopathy was examined in 40 insulin-dependent and 41 non-insulin-dependent diabetics selected consecutively from our clinic population. Multiple logistic regression analysis demonstrated a significant association between mean HbA1 and prevalence of retinopathy in both groups of patients. This association was independent of duration of diabetes which was also significantly associated with retinopathy prevalence. Hypertension and smoking were not obvious risk factors in this group of patients; an apparent association of hypertension and diabetes was entirely accounted for by a positive relationship between the presence of hypertension and duration of diabetes.