[Incidence and progression of diabetic retinopathy in low income population of Mexico City]. / Incidencia y progresión de la retinopatía diabética en población de nivel socioeconómico bajo de la Ciudad de México.

Diabetic retinopathy is one of the leading causes of preventable blindness in working age population. Diabetes mellitus and this microvascular complication affects frequently Mexican population and presents itself in severe clinical forms. There are no incidence studies of diabetic retinopathy in Mexico. The four year incidence and progression of diabetic retinopathy were investigated in low income diabetic patients of Mexico City. In the follow up phase we studied 164 patients, 76.6% of the patients studied at baseline, 63 were men and 101 women. All participants had a complete ophthalmological exam and seven field stereo photographs. All photographs were graded using internationally accepted criteria in the reading center of our institution. The four year incidence of any level of retinopathy was 22.5%. Worsening of retinopathy occurred in 20.6% and the proliferative diabetic retinopathy stage was reached in 4.5%. Incidence of diabetic retinopathy was associated to age at diagnosis of diabetes mellitus of less than 45 years and progression was associated to duration of disease of more than ten years. The four year incidence of macular edema was 8.8%. These data are important to plan strategies for prevention of blindness and the implementation of optimal care of diabetic patients in our country.

Moderate-to-severe diabetic retinopathy is more prevalent in Mexico City than in San Antonio, Texas.

OBJECTIVE: To compare the prevalence of diabetic retinopathy (DR) between low-income Mexicans from Mexico City and Mexican-Americans from San Antonio, Texas. RESEARCH DESIGN AND METHODS: We designed a cross-sectional population-based study in low-income neighborhoods of Mexico City and San Antonio. The men and non-pregnant women included in the study had NIDDM and were between 35 and 64 years of age. Ophthalmologic evaluation was performed in 414 patients, 204 in San Antonio and 210 in Mexico City. Seven field standard stereophotographs of each eye were obtained, adapting the Early Treatment Diabetic Retinopathy Study protocol, and graded at the Fundus Photograph Reading Center of the University of Wisconsin. RESULTS: Early nonproliferative DR occurred in 37 (17.6%) and 39 (19.1%) patients in Mexico City and San Antonio, respectively. Moderate-to-severe nonproliferative DR occurred in 55 (26.2%) and 37 (18.1%) patients in Mexico City and San Antonio, respectively, and proliferative DR occurred in 12 (5.7%) and 7 (3.4%) patients in Mexico City and San Antonio, respectively. Using univariate and multivariate logistic regression analysis with DR as the dependent variable, age, duration of disease, and fasting glucose concentration were positively and significantly associated with retinopathy, whereas city, systolic blood pressure, and other selected metabolic variables were not. We defined moderate-to-severe DR to include the categories of moderate-to-severe nonproliferative and proliferative DR. For this combined category, Mexico City patients with diabetes had a significantly higher prevalence (P < 0.01) than those from San Antonio when analyzed by multiple logistic regression analysis (odds ratio for Mexico City/San Antonio, 1.72; 95% CI 1.10-2.70). CONCLUSIONS: Overall prevalence of DR is similar in both cities. However, moderate-to-severe DR is significantly higher in Mexico City.

A diabetic retinopathy screening program as a strategy for blindness prevention.

The most frequent cause of preventable blindness in adults, in the developed world, is diabetic retinopathy (DR). The early treatable phase of this complication is clinically silent. In order to institute effective laser photocoagulation and prevention of blindness, timely detection is crucial. Consequently there is a need for periodic funduscopic examinations of all diabetics. Due to the high prevalence of DM in Mexico most of the primary care facilities are limited. We present the results of a DR screening program (DRSP) using a mobile unit equipped with a fundus photography camera, parked outside of a clinic. We report the prevalence of the various stages of DR and clinical characteristics observed in this population as well as our experience working in such an environment. The study period was from September 1 to December 22, 1995. All the diabetics that presented for care to the clinic were identified and all other persons were invited to participate. A total of 231 participants were invited (112 men, 119 women). Non-stereo fundus photos of two retinal fields (macula and optic disk centered) were taken with technique and classification according to international standards. Response rate to the invitation was 95.3%. Mean age was 62.4 +/- 13 years and 63.5 +/- 10 years and duration of diabetes was 12.3 +/- 10.1 years and 11.0 +/- 7.5 years for men and women, respectively. DR was detected in 38% of the cases, of these only 5.6% have received treatment. DR was uncovered in 84.5% of the cases and was associated with duration of diabetes (p < 0.001 in men and p = 0.04 in women) and hyperglycemia (in men p < 0.005, only). DR has a high prevalence in this population and can be detected through a screening program which reveals undiagnosed high risk DR in an efficient, and standardized manner.

High prevalence of cholelithiasis in a low income Mexican population: an ultrasonographic survey.

The authors present the results of a population-based survey of cholelithiasis carried out in a low-income area of Mexico City using high-resolution gallbladder ultrasound. The purpose of the study was to estimate the prevalence and selected associated risk factors of cholelithiasis (CL). The population of the studied area was 15,532 subjects, of whom 3,505 (22.6%) were eligible for the baseline survey (men and non-pregnant women between 35-64 years of age). Of this group, 1,735 (76.03%, 702 men and 1,033 women) were located for a follow-up study. Ultrasonography was performed on all except for 100 subjects who had undergone previous cholecystectomy. Crude prevalence of CL was 14.1% (95% CI 12.5-15.5). The prevalence was 5.8% (95% CI 4.1-7.5) in men and 19.7% (95% CI 17.3-22.1) in women. Presence of gallstones was associated with age, sex (men p<0.006, women p<0.001), and multiparity (p<0.002). Centrality index in men and body mass index in women were positive and significantly associated with CL when compared with subjects without CL. High levels of fasting and post-glucose load insulin in women and men respectively were associated with CL. The authors conclude that the population of this study has a high prevalence of CL and confirm some known risk factors such as age, sex, BMI and multiparity. Proper assessment of the magnitude problem and characterization of potentially modifiable risk factors will play a major role in preventing this pathology.

Nephropathy in low income diabetics: the Mexico City Diabetes Study.

Among the most serious complications associated with diabetes mellitus (DM) is nephropathy (DN). In Mexico, there is little information on the frequency and clinical characteristics of DN in the Mexican population. We present results of a population-based survey designed to estimate the prevalence of DN. The low income population consisted of 15,532 inhabitants. All 35- to 64-year-old males and non-pregnant women residing in the survey area were identified as eligible for the study (3505; 22.6%). A home interview was obtained in 2810 (80.2%). A physical exam with oral glucose tolerance test was obtained in 2282 (81.2% of those interviewed). DM was diagnosed in 304 (crude rate 13.3%). Mean age for men and women with DM was 51.6 +/- 8.4 and 52.2 +/- 7.5, respectively. Duration of DM in men was 9.2 +/- 8.1 and in women, 7.3 +/- 6.7 years. Hypertension was diagnosed in 19.8% of men and 18.1% of women. Diabetic retinopathy of any level was found in 55.4% of men and 45.7% of women. Mean glycohemoglobin in men was 9.6 +/- 2.1 and in women 9.5 +/- 2.2% (normal 4-8%). At baseline, proteinuria (1+ or more, by dipstick) was found in 24.7% of men and 9.6% of women, microalbuminuria (MA) in 84.4% of men and 63.8% of women. Quantitative albuminuria was abnormally high in 54.7% of men and 40.3% of women. In the 203 diabetics studied with 24 h urine collection for creatinine clearance, normal renal function was found in 69.1% of men and 47.5% of women, reduced renal function was found in 26% of men and 50% of women, renal insufficiency was diagnosed in 4.9% of men and 1.6% of women. One patient was on dialysis and in a subsequent follow up, we found that 2.3% of the patients had died of renal failure, six men (46-63 years) and a woman of 62 years. We conclude that DN is a very serious threat to this population. The high case fatality rate associated with this condition maintains a low prevalence. It is important to develop a program to diminish the frequency of this condition.

Prevalence of gallbladder disease and associated clinical variables in a low income population of Mexico City.

We present the results of a population-based survey carried out in a low income area of Mexico City. The aim of this study is to characterize the prevalence of clinically significant gallbladder disease (CSGD) using the self-reported history of cholecystectomy (CG) or cholelithiasis (CL) demonstrated by cholecystography and/or ultrasonography. The population of the studied area was 15,532 inhabitants, of whom 3505 (22.6%) were age eligible (35-64 year-old men and non-pregnant women). Home interviews were obtained in 2810 (80.2%). A physical and laboratory examination was performed in 2282 individuals (65.1%; 941 men and 1341 women). The prevalence of CSGD in men was 2.0% (95% confidence intervals 1.1-2.9%) and 9.2% in women (95% confidence intervals 7.7-10.7%). Patients with CSGD were older, men (p < 0.003) and women (p < 0.001). Women with CSGD had higher waist to hip circumference ratio (p < 0.06), higher fasting glucose (p < 0.03) as well as 2 h post challenge glycemia (p < 0.04) and insulinemia (p < 0.03). In the multiple logistic regression model only age (p < 0.001) and sex (p < 0.001) remained significantly associated. We conclude that CSGD is quite prevalent in this population. It is associated with age in both genders and in women, higher glucose and insulin levels. The prospective follow-up of this cohort is important since it could generate the information needed to implement a preventive program to diminish the impact of this condition.

Diabetic retinopathy in Mexico. Prevalence and clinical characteristics.

We present the results of a population based study designed to estimate the prevalence of diabetic retinopathy in a series of 284 type 2 diabetics residing in low income areas of Mexico City. These patients were identified in a survey performed between February 1990 and October 1992 (The Mexico City Diabetes Study). We located 214 (75.35%) of the original 284 patients and invited them to attend a clinic where they were interviewed and had a complete ophthalmologic examination. All participants had, in addition to the retinal examination by a certified ophthalmologist, seven fields stereo fundus photographs taken with a Topcon 50X retinal camera. Photos were taken using ASA 100 Kodak film and processed in their laboratory. All photographs were read and graded for quality and level of diabetic retinopathy (DR) in the Reading Center of the Department of Ophthalmology of the University of Wisconsin. A total of 37 (43.5%) men and 69 (53.5%) women had no evidence of DR. In 16 (18.8%) men and 21 (16.3%) women there was background DR. In 25 (29.4%) men and 30 (23.3%) women there was preproliferative DR. In 5 (5.9%) men and in 7 (5.4%) women there was proliferative DR. Macular edema was diagnosed in 7 (8.2%) men and 6 (4.7%) women, of these in 3 (3.5%) men and in 5 (3.9%) women the macular edema was central. This complication is associated with duration of diabetes, chronic poor metabolic control and microalbuminuria. A very significant proportion of cases with sight threatening DR remains undiagnosed and untreated. Consequently there is a significant number of cases developing into blindness that could have been prevented.