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Showing papers by "Ronald Klein published in 1997"



Journal ArticleDOI
TL;DR: SF-36 data may be used to predict mean QWB scores for groups of patients, and thus may be useful to modelers who are secondary users of health status profile data, and the equation may also beused to provide an overall health utility summary score to represent SF-36 profile data so long as the profiles are not severely limited by floor or ceiling effects of the SF- 36 scales.
Abstract: Background. The SF-36 and the Quality of Well-being index (QWB) both quantify health status, yet have very different methodologic etiologies. The authors sought to develop an empirical equation allowing prediction of the QWB from the SF-36. Data. They used empirical observations of SF-36 profiles and QWB scores collected in in terviews of 1,430 persons during the Beaver Dam Health Outcomes Study, a com munity-based population study of health status, and 57 persons from a renal dialysis clinic. Method. The eight scales of the SF-36, their squares, and all pairwise cross- products, were used as candidate variables in stepwise and best-subsets regressions to predict QWB scores using 1,356 interviews reported in a previous paper. The re sulting equation was cross-validated on the remaining 74 cases and using the renal dialysis patients. Results. A six-variable regression equation drawing on five of the SF- 36 components predicted 56.9% of the observed QWB variance. The equation achieved an R2 of 49.5% on cros...

211 citations


Journal Article
TL;DR: The data show a relation of hypertension to an increased incidence of retinopathy and arteriolar narrowing and suggest that pharmacologic control of blood pressure is related to a lower incidence of these anatomic retinal lesions relative to uncontrolled blood pressure.
Abstract: BACKGROUND PURPOSE: The objective was to investigate the relationship of systemic hypertension to the incidence of various retinal vascular lesions in the population-based Beaver Dam Eye Study. METHODS: Subjects aged 43 through 86 years who lived in Beaver Dam, Wisconsin between 1987 and 1988 were examined between 1988 and 1990 and 5 years later, 1993-1995. Blood pressure was measured using standardized protocols. Stereoscopic color fundus photographs were graded in a masked fashion using standardized protocols to determine the presence of retinopathy (blot hemorrhages, microaneurysms, hard and soft exudates, intraretinal microvascular abnormalities, and venous beading), retinal arteriolar narrowing, and arterio-venous nicking. People with diabetes or retinal vascular occlusions were excluded from the analyses. RESULTS: Among those examined, 2,151 (69.1%) were normotensive and 963 (30.9%) were hypertensive at baseline. Over the five-year period, retinopathy developed in 175 (6.0%), arteriolar narrowing in 282 (9.9%) and arterio-venous nicking in 201 (6.5%) nondiabetic subjects. After adjusting for age, hypertension was associated with the incidence of retinopathy (in men: relative risk [RR] 2.31, 95% confidence interval [CI] 1.54 to 3.48; in women: RR 1.61, 95% CI 1.07 to 2.43) and with arteriolar narrowing (in men: RR 1.82, 95% CI 1.25 to 2.66; in women: RR 1.36, 95% CI 1.05 to 1.77), but not with arterio-venous nicking (in men: RR 1.01, 95% CI 0.69 to 1.48; in women: RR 1.37, 95% CI 0.95 to 1.97). The five-year incidence of retinopathy and of arteriolar narrowing was higher in those subjects whose blood pressure was elevated despite use of antihypertensive medications compared with those subjects whose blood pressure was controlled with antihypertensive medications or those who were normotensive. CONCLUSIONS: These data show a relation of hypertension to an increased incidence of retinopathy and arteriolar narrowing. Furthermore, these data suggest that pharmacologic control of blood pressure is related to a lower incidence of these anatomic retinal lesions relative to uncontrolled blood pressure.

174 citations


Journal ArticleDOI
TL;DR: Findings indicate modest relations between higher pulse pressure (a presumed indicator of atherosclerotic vascular disease) and uncontrolled hypertension with increased 5-year incidence of retinal pigment epithelial depigmentation.

161 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe the incidence of cataract surgery in participants of the Beaver Dam Eye Study and report that the prior presence of posterior subcapsular catarach is the most important lens opacity.

134 citations


Journal ArticleDOI
TL;DR: It is suggested that obesity in persons with older-onset diabetes is not related to the long-term incidence of microvascular and macrovascular complications.
Abstract: Background: There are few epidemiological data describing the relationship of obesity to the incidence of microvascular and macrovascular complications in patients with diabetes. Methods: In a population-based study performed in southern Wisconsin, 1370 persons diagnosed as having diabetes when they were 30 years of age or older (mean[±SD] age, 66.6±11.3 years) participated in a baseline examination, 987 in a 4-year follow-up examination, and 533 in a 10-year follow-up examination. Height and weight were measured using standard protocols. Individuals were characterized as underweight, normal weight, overweight, and obese by body mass index (expressed as weight in kilograms divided by the square of the height in meters) status. Outcomes included incidence and progression of retinopathy, incidence of gross proteinuria, incidence of lower-extremity amputation, and death due to ischemic heart disease, death due to stroke, and all-cause mortality. Results: The prevalence of being obese was 25.2%. After other risk factors were controlled for, being underweight was associated with higher incidence of diabetic retinopathy, death from stroke, and all-cause mortality. Body mass was not associated with progression of retinopathy, incidence of gross proteinuria, amputation of a lower extremity, or death due to ischemic heart disease. Conclusions: These data suggest that obesity in persons with older-onset diabetes is not related to the long-term incidence of microvascular and macrovascular complications. Arch Intern Med. 1997;157:650-656

120 citations


Journal ArticleDOI
TL;DR: Late-stage ARM appeared to be rare among Hispanics but there was no ethnic difference in prevalence of any ARM and the 33% difference in risk among NHW by geographic location was not reduced when controlling for possible risk factors or confounders, suggesting that genetic heritage may be an important determinant of risk.
Abstract: Objectives: To determine the prevalence of age-related maculopathy (ARM) in a biethnic population and to determine if there are ethnic and/or geographic differences in the prevalence of ARM. Design: Prevalence data from 2 population-based studies, the San Luis Valley Diabetes Study (n=1541, ages 21-74 years) and the Beaver Dam Eye Study (n=3999, ages 43-74 years), were compared. Setting: Southern Colorado and central Wisconsin. Main Outcome Measure: Color stereoscopic fundus photographs were graded for ARM using the Wisconsin Age-related Maculopathy Grading System. Similar questionnaire, laboratory, and clinical data on potential risk factors were available from both studies. Results: Late-stage ARM was significantly less frequent among Hispanics than non-Hispanic whites (NHW) in Beaver Dam (odds ratio [OR]=0.07; 95% confidence interval [CI] =0.01-0.49; Hispanics vs Beaver Dam NHW). The prevalence of any ARM was significantly lower among San Luis Valley NHW (10.4%) than Beaver Dam NHW (14.3%) (OR=0.67; 95% CI=0.50-0.91). This prevalence difference was not explained by any of the risk factors examined (smoking, cardiovascular disease, diabetes, alcohol consumption, etc). The 2 NHW groups reported different European heritages. Conclusions: Late-stage ARM appeared to be rare among Hispanics but there was no ethnic difference in prevalence of any ARM. The 33% difference in risk among NHW by geographic location was not reduced when controlling for possible risk factors or confounders, suggesting that genetic heritage may be an important determinant of risk for ARM.

120 citations


Journal ArticleDOI
TL;DR: Clinicians and patients must be aware of the need for early detection of diabetic retinopathy by a thorough examination through a fully dilated pupil, to assess whether prompt treatment is needed to prevent loss of vision, and they should be skilled in their ability to diagnose the severity of diabetic Retinopathy.

113 citations


Journal ArticleDOI
TL;DR: The data confirm the need for fundus examination at the time of diagnosis of diabetes and during long‐term follow‐up and show non‐proliferative retinopathy to be associated with duration of diabetes, mean blood pressure, fasting plasma glucose, treatment with insulin and albuminuria.
Abstract: In a population-based epidemiological study, 991 Pima Indians with non-insulin-dependent (Type 2) diabetes mellitus (NIDDM) and 288 without diabetes aged > or =15 years were examined for retinopathy by fundus photography with a 45 degrees fundus camera after mydriasis. The photographs were graded using a modified Airlie-House classification scheme. The associations of several factors with retinopathy were studied by logistic regression. Non-proliferative retinopathy was present in 11.2 % (19/169) subjects at the time of diagnosis of diabetes and in 8.3% (4/48) in newly diagnosed subjects who had a documented non-diabetic oral glucose tolerance test within 4 years prior to diagnosis of diabetes. The prevalence of retinopathy in subjects with impaired glucose tolerance was 12% (8/68). Retinopathy at the time of diagnosis of diabetes was significantly associated with lower body mass index and higher systolic blood pressure but not glycaemia. Retinopathy was present in 375 (37.8 %) diabetic subjects and 14 (5.2 %) non-diabetic subjects. Among all subjects with diabetes (duration 0-37 years), stepwise multivariate analysis showed non-proliferative retinopathy to be associated with duration of diabetes, mean blood pressure, fasting plasma glucose, treatment with insulin and albuminuria. Proliferative retinopathy was seen in 34 (2.7%) of diabetic and none of the non-diabetic subjects, and was associated with 2 h post-load glucose concentrations, as well as albuminuria, insulin treatment, younger age, and diastolic blood pressure. These data confirm the need for fundus examination at the time of diagnosis of diabetes and during long-term follow-up. Albuminuria and blood pressure are potentially modifiable risk factors and the impact of treating these on incidence and progression of diabetic retinopathy need to be assessed.

83 citations


Journal ArticleDOI
TL;DR: Some risk factors for cardiovascular disease were associated with increased frequency of age-related lens opacities and age and sex influenced these relationships but did not entirely explain them.

61 citations


Journal Article
TL;DR: Clinically occult AVN of the hip is common in patients with SLE and the short term natural history of these lesions appears stable without spontaneous healing or clinical or radiographic progression and surgical intervention appears not to be indicated in these patients.
Abstract: Objective To study the natural history of clinically occult avascular necrosis (AVN) of the hip in patients with systemic lupus erythematosus (SLE). Methods Sixty-six patients with SLE (without symptoms referable to the hip) receiving at least 5 mg/day prednisone for > or = 6 months were screened by magnetic resonance imaging (MRI) for AVN of the hip. A complete MRI evaluating class and percentage of femoral head involvement, AP and lateral radiographs of the hips, bone scan, and physical examination were performed for patients with positive MRI. Medical records were reviewed for serologic and clinical variables that might predict AVN. Repeat MRI were obtained at 3, 6, and 12 months to assess possible progression or resolution of the lesion. Patients with negative screening MRI underwent repeat screening after one year to assess the one year incidence rate. Results Eleven asymptomatic hips (8%) in 8 patients (12%) had MRI documented AVN. The percentage of femoral head involvement ranged from 1 to 46%. One lesion was MRI class B, the remaining lesions were class A. The radiographic stage of 10 hips was stage 1, the MRI class B hip was stage 2. Risk factors for clinically occult AVN included Afro-American origin, Raynaud's phenomenon, migraine headaches, and a maximal corticosteroid dose of at least 30 mg/day. After 12 months, 43 of 58 patients with an initially negative MRI underwent repeat screening examinations; no new lesions were observed. Conclusion Clinically occult AVN of the hip is common in patients with SLE. The short term natural history of these lesions appears stable without spontaneous healing or clinical or radiographic progression. Risk factors for these asymptomatic lesions are similar to the risks for symptomatic AVN and surgical intervention appears not to be indicated in these patients.

Journal ArticleDOI
TL;DR: Population-based data on the frequency and incidence of retinopathy from the time of diagnosis of insulin-dependent diabetes mellitus provided by this study suggest a possible reduction in risk of developingretinopathy in those in whom glycemic control is achieved from thetime of diagnosis.
Abstract: Objective: To describe the prevalence at baseline and 4-year incidence of retinopathy and its relation to glycemic control from the time of diagnosis of insulin-dependent diabetes. Design: Geographically defined population-based study. Setting: Twenty-eight-county area in Wisconsin. Study Population: Incipient cohort of children, teenagers, and young adults (n=354) up to 30 years of age with newly diagnosed insulin-dependent diabetes. Main Outcome Measure: Diabetic retinopathy as determined by gradings from 30° color stereoscopic photographs of the Diabetic Retinopathy Study 7 standard fields. Results: The prevalence of retinopathy at diagnosis was 1.3%. Four years after diagnosis of diabetes, retinopathy was first identified in 5.1% of our cohort and in 9.7% of those 15 years of age or older. After controlling for age, subjects with a mean glycosylated hemoglobin level of 12% or greater were 3.2 times as likely (95% confidence interval, 1.1-9.9) to have retinopathy present at follow-up as were subjects with a mean glycosylated hemoglobin level of less than 12%. Conclusion: Population-based data on the frequency and incidence of retinopathy from the time of diagnosis of insulin-dependent diabetes mellitus provided by this study suggest a possible reduction in risk of developing retinopathy in those in whom glycemic control is achieved from the time of diagnosis.

01 Jan 1997
TL;DR: SF-36 data may be used to predict mean QWB scores for groups of patients, and thus may be useful to modelers who are secondary users of health status profile data, and may also be use to provide an overall health utility summary score to represent SF-36 profile data so long as the profiles are not severely limited by floor or ceiling effects of the SF- 36 scales.
Abstract: Background. The SF-36 and the Quality of Well-being index (QWB) both quantify health status, yet have very different methodologic etiologies. The authors sought to develop an empirical equation allowing prediction of the QWB from the SF-36. Data. They used empirical observations of SF-36 profiles and QWB scores collected in interviews of 1,430 persons during the Beaver Dam Health Outcomes Study, a community-based population study of health status, and 57 persons from a renal dialysis clinic. Method. The eight scales of the SF-36, their squares, and all pairwise crossproducts, were used as candidate variables in stepwise and best-subsets regressions to predict QWB scores using 1,356 interviews reported in a previous paper. The resulting equation was cross-validated on the remaining 74 cases and using the renal dialysis patients. Results. A six-variable regression equation drawing on five of the SF36 components predicted 56.9% of the observed QWB variance. The equation achieved an R 2 of 49.5% on cross-validation using Beaver Dam participants and an R 2 of 56.7% with the renal dialysis patients. An approximation for computing confidence intervals for predicted QWB mean scores is given. Conclusion. SF-36 data may be used to predict mean QWB scores for groups of patients, and thus may be useful to modelers who are secondary users of health status profile data. The equation may also be used to provide an overall health utility summary score to represent SF-36 profile data so long as the profiles are not severely limited by floor or ceiling effects of the SF-36 scales. The results of this study provide a quantitative link between two

Journal ArticleDOI
TL;DR: Most risk factors associated with self reported glaucoma in people with diabetes cannot currently be modified to decrease incidence and may be particularly in need of specialised ophthalmic observation.
Abstract: AIM—To determine the incidence of self reported glaucoma in a group of people with diabetes mellitus. METHODS—In an 11 county area in southern Wisconsin, a cohort of people with diabetes mellitus was identified and characterised by history, physical examination, fundus photographs, and laboratory evaluation in 1980-2 (n=2366). The cohort was followed for 10 years with 891 younger onset and 987 older onset people participating in at least one follow up examination. RESULTS—The 10 year incidence of glaucoma was 3.7% in younger onset people, 6.9% in older onset people not using insulin, and 11.8% in older onset people using insulin. Univariate analyses revealed that in younger onset people greater body mass index, older age, longer duration of diabetes, history of cataract surgery, and increased severity of diabetic retinopathy at baseline conferred increased risk. In older onset people using insulin, older age and longer duration of diabetes, higher intraocular pressure, and history of cataract surgery at baseline were associated with increased risk of glaucoma. In multivariate analyses, only age was significantly related to increased incidence in younger onset people and age, intraocular pressure, and insulin use were significantly associated with increased risk in the older onset group. CONCLUSION—Most risk factors associated with self reported glaucoma in people with diabetes cannot currently be modified to decrease incidence. Older onset people who are at increased risk of many ocular complications of diabetes may be particularly in need of specialised ophthalmic observation.

Journal ArticleDOI
TL;DR: To assess primary care physicians' self-reported practice patterns for the screening and detection of diabetic retinopathy relative to published guidelines, a mailed questionnaire was used to identify and survey physicians.
Abstract: ARCHIVES OF FAMILY MEDICINE Primary Care Physicians' Practice Patterns and Diabetic Retinopathy: Current Levels of Care Stephanie Kakos Kraft, MPH; David G. Marrero, PhD; Emmanuel N. Lazaridis, PhD; Naomi Fineberg, PhD; Chunfu Qiu, PhD; Charles M. Clark, Jr, MD Background: Diabetic retinopathy is a costly and prevalent complication of diabetes mellitus. Objective: To assess primary care physicians' self-reported practice patterns for the screening and detection of diabetic retinopathy relative to published guidelines. Participants and Methods: All primary care physicians (defined as general internists, family practitioners, and general practitioners) in Indiana were identified and surveyed using a mailed questionnaire. Of 2390 physicians, 1508 (63%) responded and were determined to be eligible. Of these 1508 physicians, 1058 (70%) completed all or some of the eye care-related questions. For each eye care practice, physicians were asked to specify the proportion of patients to which the practice was applied and the frequency (eg, every

Journal ArticleDOI
TL;DR: This work investigates risk factors for incidence and progression of diabetic retinopathy in a group of patients with older onset diabetes from the Wisconsin Epidemiological Study of Diabetic Retinopathy using smoothing spline ANOVA methods.
Abstract: Smoothing spline ANOVA (ANalysis Of VAriance) methods provide a flexible alternative to the standard parametric GLIM (generalized linear models) methods for analysing the relationship of predictor variables to outcomes with data from large epidemiologic studies. These methods allow the visualization of relationships not readily fit by simple GLIM models, and provide for the ability to visualize interactions between the variables. At the same time, they reduce to GLIM models if the data suggest that the added flexibility is unwarranted. Using this method, we investigate risk factors for incidence and progression of diabetic retinopathy in a group of patients with older onset diabetes from the Wisconsin Epidemiological Study of Diabetic Retinopathy. We carry out four analyses to illustrate various properties of this class of methods. Some of the results confirm previous findings with use of standard methods, while others allow the visualization of more complex relationships not evident from the application of parametric methods.

Journal ArticleDOI
TL;DR: Overall prevalence of diabetic retinopathy is similar in both cities, however, moderate-to-severe DR is significantly higher in Mexico City.
Abstract: 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 CONCLUSIONS Overall prevalence of DR is similar in both cities. However, moderate-to-severe DR is significantly higher in Mexico City.

Journal ArticleDOI
TL;DR: Incorporating fat-modified foods into food frequency questionnaires will improve the ability of researchers to correctly classify fat exposures and to evaluate potentially important relationships between fat intake and disease risk.
Abstract: Objective To determine the extent to which incorporating fat-modified foods into a food frequency questionnaire influences the agreement of energy and nutrient estimates with estimates obtained from food records. Design Subjects completed four 2-day food records at 3-month intervals. At the end of the recording period, a food frequency questionnaire was administered to assess usual daily intake during the preceding year. Subjects/setting One hundred and three subjects selected from a population-based sample of adults participating in the Beaver Dam Eye Study. Statistical analyses performed Subjects were categorized into three groups on the basis of their frequency of consumption of fat-modified foods. For each group, correlations were calculated between food record estimates and estimates obtained from the original food frequency questionnaire, the original with a low-fat option, and the fat-modified questionnaire. Results For persons categorized as high consumers of fat-modified foods, incorporating questions regarding the consumption of these products resulted in higher correlations with food record estimates (original vs fat-modified version) for percentage of energy from total fat (.32 vs .47), saturated fat (.20 vs .41), oleic acid (.32 vs .50), and linoleic acid (.40 vs .46). High consumers differed in several characteristics that could be associated with disease risk (eg, higher ratios of serum total cholesterol to high-density lipoprotein cholesterol). Conclusions Failure to account for the consumption of fat-modified foods in epidemiologic studies may result in misclassification of fat exposures. Because patterns of misclassification could be different for those at risk for disease, results of epidemiologic studies could be biased if these foods are excluded. Thus, incorporating fat-modified foods into food frequency questionnaires will improve the ability of researchers to correctly classify fat exposures and to evaluate potentially important relationships between fat intake and disease risk. J Am Diet Assoc. 1997; 97: 860–866 .

Journal ArticleDOI
TL;DR: Change in intraocular pressure in this adult population was associated with increased optic disc cupping, and this finding would lend support to the practice of periodic follow-up of older adults who have shown changes in their intraocular Pressure.
Abstract: PURPOSE. To determine the relationship of change in vertical optic disc cupping to change in intraocular pressure over a five-year interval. METHODS. Non-simultaneous stereoscopic photographs were taken of optic discs of participants in the baseline and follow-up examinations of The Beaver Dam Eye Study cohort. Optic discs and cups were measured and other disc features were graded according to a standard protocol by trained graders. Intraocular pressures were measured by Goldmann applanation tonometry. RESULTS. Change in pressure was significantly associated with change in vertical cup-to-disc ratio. Incident disc hemorrhage, flattened temporal rim, notching, cup reaching disc margin, and undercutting were not significantly associated with change in intraocular pressure. CONCLUSION. Change in intraocular pressure in this adult population was associated with increased optic disc cupping. This finding, if confirmed, would lend support to the practice of periodic follow-up of older adults who have shown chan...

Journal ArticleDOI
TL;DR: In this population of people with diabetes onset before 30 years of age who were receiving primary care in an 11-county area of south central Wisconsin in 1980, level of glycemia is related to the frequency of hypoglycemic reactions.
Abstract: OBJECTIVE To evaluate whether there has been a change in frequency of hypoglycemic reactions associated with use of insulin of animal or human type. RESEARCH DESIGN AND METHODS Data are from a longitudinal population-based study of people with diabetes onset before 30 years of age who were receiving primary care in an 11-county area of south central Wisconsin in 1980. Interviews of study participants were conducted regarding occurrence of hypoglycemic reactions and the frequency, dose, and type of insulin used. At the 4-year follow-up, 727 of the 765 subjects were using only animal insulin and 33 were using human insulin; by the 10-year follow-up, 352 were using animal insulin and 388 were using human insulin. RESULTS Those using animal insulin reported fewer hypoglycemic reactions than did users of human insulin ( X 12 = 4.66, P = 0.03). Those who changed insulin type between visits were no more likely to report more hypoglycemic reactions during the year before the visit than those who remained on the same type at the two examinations ( X 24 = 3.37, P = 0.50). At the 10-year exam, users of human insulin were more likely to be taking multiple doses of insulin (86.6%) than were users of animal insulin (73.9%; P < 0.0001). In multiple logistic regression, the following variables were significantly related to the frequency of hypoglycemic reactions at the 10-year visit: body mass index (lower), glycosylated hemoglobin (lower), and being female. CONCLUSIONS In this population, level of glycemia is related to the frequency of hypoglycemic reactions. While type of insulin (human vs. animal) may be related to glycemia, it appears to have little independent effect on the frequency of reactions.

Journal ArticleDOI
TL;DR: Data suggest that Ca2+ homeostasis is disrupted in the same age groups that are most vulnerable to osteoporosis, including men and women over 43 years old.

Journal ArticleDOI
TL;DR: Lesions associated with early age-related maculopathy were distributed in specific patterns in specific subfields of the human retina as mentioned in this paper, including central, inner superior, inner nasal, inner inferior, inner temporal, outer superior, outer nasal, outer inferior, and outer temporal.


Journal ArticleDOI
TL;DR: A conclusion that states that the study "showed that meticulous metabolic control did not prevent the onset or the progression of retinopathy, or affect visual acuity over the course of 18 months after good glycemic control was achieved" may not be warranted.
Abstract: Readers would benefit from further scientific backup on the assumption mentioned under \"Ophthalmologic assessment,\" which states that \"[f]or purposes of classification, if retinopathy severity could not be graded in an eye, this eye was considered to have the same score as the participant's other eye\" (1). Surprisingly, visual acuity was graded utilizing Snellen visual acuity charts, ignoring the benefit of using better and more well-known charts for testing visual acuity. The Standardized Visual Acuity Chart (e.g., Bailey-Lovie or Early Treatment Diabetic Retinopathy Study) (2,3) was designed specifically to correct the deficiencies of the Snellen chart, offering the same number of letters per line, a logarithmic progression in the size of the letters, and an equivalent difficulty for reading among lines. Measurements with the Standardized Visual Acuity Chart provide reproducible visual acuity information in a format that facilitates quantitative data analysis (3). Very useful guidelines on the standardization of visual acuity measurements in clinical research have been recently published (4). Tables 1 and 5 of Emanuele et al. (1) pretend to establish the absence of a confounding role of several baseline variables. These tables disclose P values as a proof that no significant differences between the standard and intensive treatment groups existed at baseline. The use of P values in this context is misleading, since these are strictly dependent on sample size and their role in evaluating confounding is pointless. Methods to evaluate the role of baseline variables as confounding factors include restriction, pairing, and multivariate analysis. The sample size calculations indicated that the study had an 80% power to detect a 1.5-2.0 difference in retinopathy levels between treatment groups. The study showed that at baseline, the retinopathy levels were 3.2 ± 0.4 in the standard treatment group and 2.9 ± 0.3 in the intensive treatment group. Readers would also benefit by knowing why a 1.5-2.0 difference was chosen as the clinically significant difference to be detected by the study. By treating a group of patients with a relatively low level of baseline retinopathy, on whom treatment compliance was to be expected in both treatment groups (based on the eligibility criteria) and following them for 24 months, it may be likely that the minimal difference to be detected between the two groups might have been large, and a smaller difference between groups may have gone undetected. Until these points are addressed, it is my impression that a conclusion that states that the study \"showed that meticulous metabolic control did not prevent the onset or the progression of retinopathy, or affect visual acuity over the course of 18 months after good glycemic control was achieved\" may not be warranted.