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Revista Brasileira de Oftalmologia

Print version ISSN 0034-7280

Rev. bras.oftalmol. vol.73 no.3 Rio de Janeiro May/June 2014 

Artigos originais

Epidemiological and ophthalmological findings in diabetic patients examined in a general hospital

Mariluce Silveira Vergara 1  

André Simoni de Jesus 1  

Lucia Campos Pellanda 2  

Manuel A P Vilela 2   3  

1Specialisation Course in Ophthalmology “Professor Ivo Correa-Meyer”, Porto Alegre/RS, Brazil.

2Post-Graduation Programme, Institute of Cardiology, Cardiology University Foundation; Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre/RS, Brazil.

3Federal University of Pelotas, Pelotas/RS, Brazil.



To evaluate the association between epidemiological and ophtalmological findings in diabetic patients.


Cross-sectional study. We selected consecutively diabetic patients examined during 2011 which responded to a questionnaire and examination.


The sample comprised 103 patients, of whom 72 (69.9%) were female, 66 (64%) were Caucasian, average age 59 (+/- 9,21) years, 64% reported minimum wages, 58.2% did not finish elementary school, 75.7% reported family history of diabetes, 45.6% reported regularly perform metabolic control, 54.3% did not receive special nutritional care. On examination, 72.8% had visual acuity of 20/40. There was a significant association between retinal complications and insulin usage (OR=8,3; p=0,003), and between low visual acuity and age (OR=11,8; p=0,003) and insulin (OR=5,48, p=0,021), as well with lower education and income.


In this low-income and low-education population, glycemic control was poor, and related to the development of diabetic retinopathy and the consequent low vision. These findings emphasize the need to adopt broader strategies to improve control and prevention of diabetes mellitus.

Key words: Diabetes mellitus; Diabetic retinopathy; Blindness


According to the World Health Organization, diabetes mellitus (DM) currently affects approximately 171 million people worldwide(1). Of these, probably 10 to 20% have some form of retinopathy and about 1.78 million are blind. An estimated 7.7% of the population aged 20-70 years (439 million) will have the disease by 2030, of which 70% or more will be concentrated in developing countries(2). This difference is based on factors such as population growth, ageing, inadequate diet, obesity, and sedentary lifestyle, in addition to reductions in the fasting glucose thresholds currently used for diagnosing DM(1-5).

In Brazil, according to the Brazilian Diabetes Society(3), the prevalence of DM in persons aged 30-69 years is 7.6%; São Paulo, Porto Alegre and João Pessoa are the capitals with the highest prevalences.

Most diabetic patients, with rare exceptions(4), do not undergo preventive ophthalmic examination with the recommended frequency and they ignore the consequences of the disease and the importance of prevention(5-13). The most efficient method for evaluating the population utilises non-mydriatic cameras and specialised image-processing centres(14-33).

The present study aimed to investigate the ophthalmic status of diabetic patients in the Brazilian public health system (SUS) in the city of Viamão, a municipality adjacent to Porto Alegre in the state of Rio Grande do Sul.


This study had an observational, cross-sectional design and it was approved by the Research Ethics Committee of the Institute of Cardiology of Viamão Hospital. Inclusion criteria were: diabetic patients covered by the SUS seen in 2011 at the ophthalmology outpatient clinic of the Institute of Cardiology of Viamão Hospital.

All diabetic patients seen at the clinic were invited to participate in the study. After providing their informed consent, they answered a questionnaire and underwent a complete ophthalmic examination.

The questionnaire included questions on sex, age, race, income, education, family history of diabetes, presence of other systemic diseases, a self-assessment of diabetes control (good, when following all the routine guidelines; moderate, in cases of partial adhesion; and bad, when the guidelines were not followed), diet (adhesion, supervision by a nutritionist), frequency of medical evaluations, knowledge of the potential consequences of diabetes, and frequency of fasting glucose testing (including tests with personal glucometers). Medical records were reviewed for information on glycosylated haemoglobin (last available result) and other non-ocular complications associated with diabetes.

All patients underwent an assessment of best corrected visual acuity (on a logMAR chart), intrinsic and extrinsic eye movements, applanation tonometry (Perkins), anterior slit lamp biomicroscopy, and binocular indirect ophthalmoscopy under mydriasis. Patients who did not fully provide their informed consent, answer the entire questionnaire, or undergo eye examination were excluded from the study.

Patients who had been fasting for more than 2 hours underwent capillary glucose testing (Accu-Chek Performa glucometer, Roche, Germany).

All the collected information was stored in a database using Microsoft Office Excel 2003 and analysed using Stata 12.1 software.

Statistical analysis included a description through means and standard deviations or proportions, bivariate Pearson or Spearman correlations, and multivariate analysis (logistic regression). Results with p<0.05 were considered statistically significant.


The sample included 103 patients examined between March and December 2011. The mean age of respondents was 59.6 (41-85) years. Most patients were white (64%), followed by black (26%) and mixed-race (10%) patients. Table 1 shows the complete data.

Table 1 Epidemiological characteristics of the study population 

Variable   (%)
Sex Female (69,9)
Race White (64)
  Black (26)
  Mixed-race (10)
Monthly family income Up to the minimum wage (64)
  >1 and < 3 times the minimum wage (30)
  > 3 times the minimum wage (6)
Education Iliterate (18,5)
  Incomplete elemantary school (58)
  Elemantary school education (18,5)
  High school education or higher (5)
Familiar kistory of DM Yes (76)
Type of diabetes Type 2 (99)
Concomitant diseases Systematic arterial hypertension (51)
  Ischemicheart disease (7)
  Acute myocardial infarction (9)
  Stroke (7)
  Renal failure (2)
Metabolic control Good (39)
  Moderate (46)
  Poor (15)
Diet Incomplete adhesion (72)
Supervision by a nutricionist No (72)
Frequency of medical visit Every 6 months (48)
  Every 3 months (35)
  Yearly (17)
Frequency of capillary glucose testing Once a week (25,5)
Once a month (36,5)
  Quarterly (31,5)
  Never (6,5)
Glycosylated heamoglobin Average (8,3)
Treatment Oral hypoglycaemic agent (71)
  Oral hypoglycaemic agent + insulin (28)
  Insulin (1)

On examination, visual acuity was equal to or better than 20/40 in 73% of patients, and between 20/50 and no light perception in 27%. Fundus examination was normal in 53% of patients, non-proliferative diabetic retinopathy (DR) without macular oedema was found in 32%, non-proliferative DR with macular oedema in 8%, and high-risk proliferative DR in 6%.

The glucometer test was performed on 60% of patients, with the following results: d”200 mg/dl in 31%; 201-300 mg/dl in 18%; 301-400 mg/dl in 9%; 401-500 mg/dl in 1%; and e”501 mg/dl in 1% (59% had been fasting for more than 6 hours).

Logistic regression controlling for other variables found statistically-significant correlations between retinal complications and insulin use (OR=8.3, p=0.003); low visual acuity and insulin use (OR=5.48, p=0.021); and low visual acuity and age (OR=11.8, p=0.003) (Table 2).

Table 2 Results of logistic regression for correlations between low visual acuity and other variables. 

Low visual acuity Odds ratio Standard error P Value [95% CI]
Sex 0,71 0,52 0,65 0,17-3,01
Race 2,03 1,06 0,17 0,72-5,67
Income 0,62 0,49 0,55 0,13-2,96
Education 0,51 0,30 0,25 0,16-1,62
Family history 0,40 0,30 0,23 0,92-1,77
Metabolic control 0,74 0,32 0,5 0,31-1,75
General complications 0,63 0,20 0,16 0,32-1,20
Blood glucose 1,84 0,62 0,07 0,94-3,58
Insulin use 5,48 4,03 0,02 1,3-23,2
Age 11,8 9,94 0,003 2,26-61,5
Glycosylated haemoglobin 1,23 1,01 0,8 0,24-6,16
Diet 1,3 1,22 0,79 0,20-8,3

[95% CI = 95% Confidence interval]


In this study, the typical participant was a low-income, low-education adult patient with type 2 diabetes using oral hypoglycaemic agents. Almost half of patients had retinopathy.

Most patients underwent medical follow-up every three to six months but were unaware of the systemic diseases associated with diabetes and did not adhere adequately to medical recommendations.

Most patients had high capillary glucose levels, which were considered reliable as they were in agreement with glycosylated haemoglobin(34-36). These results show that metabolic control was poor even though patients had access to specialist care.

Statistically-significant correlations were found between insulin use and retinopathy, low visual acuity and age, and low visual acuity and the need for insulin therapy. These findings reproduce the conditions of SUS patients in our region(6,7) and are in agreement with most studies conducted in different locations(5-13,24-29), which show that longer disease duration and greater difficulty controlling the disease (requiring insulin use) are associated with more severe ocular manifestations.

On average, 50-90% of diabetic patients are not evaluated under optimal conditions(1,2). An exception to this is found in Peto and Tadros(4), where 78% of diabetic patients over 15 years of age in the UK underwent retinal assessment with non-mydriatic cameras. Greater access to health care does not imply that all forms of treatment are available(37), which can affect outcomes related to disease control(30-33). In our environment, Guedes et al.(38) studied a Family Health Programme and stressed the need to provide better treatment and education to diabetic patients, even though the authors used a small sample and had a high number of study drop-outs.

Reducing the incidence of blindness and its associated costs requires early detection and rigorous, universal, multidisciplinary, preventive specialist care. 30-3333 The main risk factors for RD are related to disease duration, metabolic control, the type of diabetes, and treatment (with a lower risk in patients treated with diet and a higher risk in insulin users), as well as other factors (genetic factors, systemic arterial hypertension, smoking, pregnancy, and nephropathy)(24-29). Considering that disease duration and the type of diabetes are related to DR(26-29) and that a predominance of high-risk patients are found in our public health system, implementing targeted educational programmes and using non-mydriatic digital systems to acquire fundus images processed through telemedicine methods is required to reduce the incidence of blindness.


This study showed that essential elements in the management of RD in our health system, such as knowledge of the disease, periodic controls, nutritional support, and adherence to medical treatment, are still largely lacking. Patients with longer disease duration or requiring a greater number of drugs are very likely to suffer functional vision loss and severe retinal damage.

Work conducted at the Institute of Cardiology of Viamão Hospital and the Federal University of Pelotas.


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Received: October 18, 2012; Accepted: June 23, 2014

Autor correspondente: Manuel A P Vilela, Rua Félix da Cunha, 496, CEP 90570-000 - Porto Alegre (RS), Brasil.

The authors declare no conflict of interest.

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