Reply to: "Agreement analysis" / Respuesta a: "Análisis de concordancia"

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Agreement between Pentacam and handheld Auto-Refractor/Keratometer for keratometry measurement.

OBJECTIVE: This study was conducted to evaluate the level of agreement in keratometry measurements between a rotating Scheimpflug imaging-based system (Pentacam) and a handheld auto-refractokeratometer (handheld NIDEK ARK-30). METHOD: This analytical cross-sectional study was conducted in the right eyes of 579 subjects. Keratometry measurements were conducted with the Pentacam and the handheld NIDEK ARK-30 systems. The SPSS Software version 22 and MedCalc V3 were applied to estimate descriptive statistics using paired t-test, Pearson correlation coefficient, 95% limits of agreement (LoA), and Bland-Altman plot. RESULTS: In the total sample, the inter-device difference in the mean flat and steep keratometry values was -0.266 diopter (D) (P-value<0.001) and 0.052D (P-value=0.093), respectively. There was a significant difference in mean flat keratometry between the two devices in all groups of refractive errors (paired difference <0.5D and P-value<0.001). The difference in mean steep keratometry was significant only in myopic subjects (P-value=0.046). The 95% LoA between the two devices measurements was 2.51D, 3.98D, and 6.37D for flat keratometry and 2.6D, 3.2D, and 3.9D for steep keratometry in emmetropic, myopic, and hyperopic subjects, respectively. CONCLUSION: Our study showed relatively wide limits of agreement between handheld NIDEK ARK-30 and Pentacam; therefore, these devices cannot be used interchangeably for measuring corneal curvature.

Ocular abnormalities in multi-transfused beta-thalassemia patients.

AIMS: The aim of this study was to assess ocular changes in thalassemia patients who have received multiple transfusions and chelate binding therapy in order to avoid iron accumulation. SETTINGS AND DESIGN: A cross-sectional study. SUBJECTS AND METHODS: A total of 54 thalassemia major patients were selected as case group, and 54 age- and sex-matched healthy subjects were regarded as a control group. Ocular examination included visual acuity, refraction testing, slit lamp examination, funduscopy, tonometry, perimetry, tear break-up time test, and color vision testing were performed for all the participants. We computed the frequency and duration of blood transfusion, the mean serum ferritin level, pretransfusion hemoglobin concentration, and type, duration, and daily dose of chelation therapy for thalassemia patients based on their records. STATISTICAL ANALYSIS USED: All data analysis was performed using SPSS, version 19. RESULTS: All the thalassemic patients were asymptomatic, but abnormal ocular findings (dry eye (33.3%), cataract (10.2%), retinal pigment epithelium degeneration (16.7%), color vision deficiency (3.7%), and visual field defects (33.7%)) were seen in 68.5% of thalassemic group. The prevalence of ocular abnormalities in normal group was 19.4%, which was significantly lower than that in thalassemia patients (P = 0.000). No significant correlation was found between ocular abnormalities and mean serum ferritin level (P = 0.627) and mean hemoglobin concentration (P = 0.143). Correlation of number of blood transfusion with the presence of ocular abnormalities was found to be statistically significant (P = 0.005). CONCLUSIONS: As life expectancy for beta-thalassemia patients extends, regular ophthalmological evaluation to detect early changes in their ocular system is recommended.

Aldose reductase C-106T gene polymorphism in type 2 diabetics with microangiopathy in Iranian individuals.

BACKGROUND: Aldose reductase (AR) is the rate-limiting enzyme in the glucose metabolism, which has been implicated in the pathogenesis of diabetic microvascular complications (MVCs). Frequent C-106T polymorphism in the promoter of the AR gene may change the expression of the gene. AIMS: The aim of the following study is to study the association between AR C106T genotypes and diabetic MVCs in Iranian population. MATERIALS AND METHODS: We included 206 type 2 diabetic patients categorized into two groups according to the presence or absence of diabetic microangiopathy. The cases of interest were diabetic neuropathy, retinopathy and nephropathy identified during clinical and or laboratory examination. In addition, 114 age- and sex-matched individuals were selected to serve as a control group. AR genotyping was done using an amplification gel electrophoresis. RESULTS: The frequency of CC genotype was specifically higher in subjects with diabetic retinopathy as compared to those without it (53.2% vs. 38.1%, P = 0.030). Patients with diabetic microangiopathy in general; however, did not differ significantly between AR genotype groups. CONCLUSION: The C-106T polymorphism in the AR gene is likely a risk factor for development of only retinal complication of diabetes microvascular in Iranian individuals.

Relationship between Type 2 Diabetic Retinopathy and Periodontal Disease in Iranian Adults.

BACKGROUND: Periodontal disease in diabetic patients can compromise a patient's ability to maintain a proper metabolic control and may be associated with diabetic complication. AIMS: This study was designed to evaluate the frequency of periodontal disease in patients with type 2 diabetes mellitus (DM) and how this was related with the presence of diabetic retinopathy (DR). MATERIALS AND METHODS: A comparison was made of periodontal parameters (plaque index (PI), community periodontal index of treatment needs (CPITN), periodontal disease severity measured in quartiles of probing depth (PD), and clinical attachment loss (CAL)) in a group of diabetic patients with retinopathy (n = 84) versus a group of diabetic patients without retinopathy (n = 129). In addition, 73 age- and sex-matched individuals were selected to serve as the control group. Analysis was performed to evaluate the relationships between periodontal disease and DR. RESULTS: In terms of PI, no statistically significant differences were observed, so, oral hygiene was similar in both groups. Diabetic patients with retinopathy had greater CPITN (P < 0.001) and more severe periodontal disease (P < 0.001) than no retinopathy. Also, our results indicated a relationship between type 2 DM and periodontal disease. CONCLUSIONS: The patients with diabetes retinopathy appear to show increased periodontal disease susceptibility.

Haptoglobin polymorphism in individuals with type 2 diabetic microangiopathy.

BACKGROUND: Haptoglobin is an acute phase protein with antioxidant and immunomodulatory properties. Gene polymorphism may be a risk factor for diabetic vascular disease in Iranian population. AIMS: The study investigates the existence or not of an association between haptoglobin genotypes and prevalence of diabetic microangiopathy in individuals with type 2 diabetic microangiopathy. MATERIALS AND METHODS: We included 206 type 2 diabetic patients (<5 years duration) categorized into two groups according to the presence or absence of diabetic microvascular complications. The cases of interest were diabetic neuropathy, retinopathy, and nephropathy identified during clinical and or laboratory examination. In addition, 114 age- and sex-matched individuals were selected to serve as a control group. Haptoglobin genotyping was done using an amplification gel electrophoresis. RESULTS: The frequency of haptoglobin phenotype 2-1 in diabetic patients was 70/206 (33.9%) as compared with 54/114 (47.3%) in nondiabetics (P = 0.01). However, the frequency of haptoglobin phenotype 2-2 was greater in diabetics (126/114, 61.1%) than in those without diabetes (56/114, 49.1%; P = 0.02). Patients with diabetic microangiopathy; however, did not differ significantly between haptoglobin phenotype groups. CONCLUSIONS: Haptoglobin phenotype 2-2 is considered to be a major susceptibility gene for type 2 diabetic patients. Moreover, haptoglobin phenotype 2-1may be good prognostic factors for the development of diabetes mellitus.