Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes mellitus and a leading cause of visual impairment and blindness among working-age adults worldwide. As the global burden of diabetes continues to rise, the incidence of DR is also expected to increase, particularly in low- and middle-income countries, including India (1). DR progresses through various stages, from non-proliferative to proliferative forms, with the severity being influenced by a range of systemic, metabolic, and lifestyle-related factors. Early detection and intervention can prevent or delay the progression to vision-threatening stages (2). Understanding the determinants that influence the severity of DR is essential for optimizing screening strategies and clinical management.

Multiple studies have identified poor glycemic control, long duration of diabetes, hypertension, dyslipidemia, nephropathy, and anemia as significant contributors to the development and progression of DR (3). However, the interaction of these factors and their association with the severity of DR remains complex and not fully understood, particularly in specific populations such as those attending tertiary care hospitals. Previous research from India has reported regional variations in the prevalence and severity of DR, influenced by socioeconomic status, healthcare access, and comorbidities (4, 5). While studies have explored individual risk factors, few have comprehensively evaluated their combined impact on DR severity in a tertiary care setting.

There is a critical need to assess these factors systematically in order to bridge the existing knowledge gap regarding predictors of DR severity in resource-constrained settings. Moreover, there is limited data on how demographic and biochemical variables correlate with clinical staging of DR in hospital-based populations. The current study aims to evaluate the clinical, biochemical, and demographic factors associated with the severity of diabetic retinopathy among patients attending a tertiary care center. This evaluation will help identify high-risk individuals who may benefit from intensified screening and management, thereby contributing to the prevention of visual disability in diabetic populations.

Study Design and Setting

This was a hospital-based, cross-sectional observational study conducted in the Department of Ophthalmology, Mamata Medical College and General Hospital, Khammam, Telangana. The study was carried out over a period of six months, from January 2024 to June 2024.

Study Population and Sample Size

A total of 50 patients diagnosed with diabetic retinopathy were included in the study. These patients were selected from those attending the ophthalmology outpatient department during the study period. The sample size was determined based on the availability of eligible patients within the study period and logistical feasibility.

Inclusion Criteria

• Patients aged 30 years and above.
• Diagnosed cases of type 2 diabetes mellitus.
• Clinical evidence of diabetic retinopathy on fundus examination.

Exclusion Criteria

• Patients with dense media opacities such as mature cataract or vitreous hemorrhage that obscured fundus view.
• History of previous ocular surgery, trauma, or laser photocoagulation.
• Co-existing retinal disorders such as retinal vein occlusion or age-related macular degeneration.
• Type 1 diabetic patients.

Ethical Considerations

The study protocol was approved by the Institutional Ethics Committee of Mamata Medical College, Khammam. Informed written consent was obtained from all participants after explaining the purpose and nature of the study.

Data Collection

After recruitment, detailed demographic and clinical data were collected using a structured proforma. This included:

• Demographic details: Age, sex, duration of diabetes, family history.
• Systemic history: Presence of hypertension, nephropathy, anemia, dyslipidemia, and treatment history.
• Ophthalmic symptoms: Blurring of vision, floaters, and visual field changes.

Ophthalmological Examination

All patients underwent a complete ophthalmological assessment, which included:

• Best-corrected visual acuity (BCVA) using Snellen’s chart.
• Intraocular pressure measurement using a non-contact tonometer.
• Anterior segment evaluation using slit-lamp biomicroscopy.
• Fundus examination under mydriasis using:

o             Direct ophthalmoscopy

o             Indirect ophthalmoscopy

o             Slit-lamp biomicroscopy with a +90D lens.

• Fundus photography was done in selected cases for documentation and staging.

Grading of Diabetic Retinopathy

The severity of diabetic retinopathy was classified based on the Early Treatment Diabetic Retinopathy Study (ETDRS) classification into:

• Mild Non-Proliferative Diabetic Retinopathy (NPDR)
• Moderate NPDR
• Severe NPDR
• Proliferative Diabetic Retinopathy (PDR)

Laboratory Investigations

Systemic parameters were assessed through the following tests:

• Fasting Blood Sugar (FBS)
• Postprandial Blood Sugar (PPBS)
• Glycosylated Hemoglobin (HbA1c)
• Serum Creatinine
• Lipid profile (Total cholesterol, HDL, LDL, Triglycerides)
• Urine albumin levels

Statistical Analysis

Data were entered and analyzed using SPSS software version 25.0. Descriptive statistics such as mean, standard deviation, and percentage were used to summarize data. The association between the severity of diabetic retinopathy and various risk factors was evaluated using Chi-square test for categorical variables and Pearson’s correlation coefficient for continuous variables. A p-value of less than 0.05 was considered statistically significant.

Table 1: Demographic Characteristics of the Study Population (n = 50)

The mean age of the study participants was 56.8 ± 9.4 years, indicating that most patients were in the middle to older age group, which aligns with the typical onset and progression pattern of diabetic retinopathy. There was a male predominance (60%), possibly reflecting greater health-seeking behavior among men or gender-based differences in diabetes complications. The mean duration of diabetes was 10.2 ± 4.6 years, suggesting that prolonged exposure to hyperglycemia contributes significantly to the development of retinopathy. A positive family history of diabetes was present in 36% of the patients, indicating a potential genetic predisposition or familial clustering of risk factors associated with diabetes and its complications (Table 1).

Table 2: Systemic History of the Study Population (n = 50)

In this study, hypertension (56%) was the most common comorbidity, followed by dyslipidemia (40%), nephropathy (28%), and anemia (22%), all of which are known to influence diabetic retinopathy progression. Most patients were on oral hypoglycemic agents (52%), while 24% were on insulin and 16% on combined therapy, indicating varied levels of glycemic control. Only 8% managed diabetes through diet and lifestyle alone. These findings highlight the importance of controlling systemic risk factors to prevent worsening of retinopathy.

Blurring of vision was the most common symptom, reported by 76% of patients, reflecting early macular involvement or refractive changes due to diabetic retinopathy. Floaters were seen in 24%, often associated with vitreous changes or hemorrhage. Visual field changes, noted in 12%, may indicate advanced retinal damage. Interestingly, 10% of patients had no visual complaints, underscoring the importance of routine screening even in asymptomatic individuals (Figure 1).

Table 3: Summary of Ophthalmological Findings (n = 50 patients / 100 eyes)

In this study, moderate visual impairment (6/18 to 6/60) was the most common finding, seen in 48% of eyes, followed by severe impairment in 30%, indicating significant functional impact of diabetic retinopathy. Normal vision was preserved in only 22% of eyes. The mean intraocular pressure was 16.4 ± 3.2 mmHg, with elevated IOP (>21 mmHg) in 6% of eyes. Anterior segment evaluation revealed age-related cataract in 34% and neovascularization of the iris (NVI) in 6% of eyes, suggesting advanced proliferative disease in a subset of patients (Table 3).

Table 4: Fundus Findings Based on Diabetic Retinopathy Severity (n = 100 eyes)

Among the 100 eyes examined, moderate NPDR was the most common stage (34%), followed by severe NPDR (24%) and proliferative DR (22%), indicating that over 45% of eyes had sight-threatening disease. Mild NPDR was seen in 20%. Macular edema was present in 28% of eyes 16% focal and 12%. Neovascular changes were noted in 10% (NVE) and 4% (NVD), while complications like vitreous hemorrhage (3%) and tractional retinal detachment (1%) reflect advanced proliferative changes requiring prompt intervention (Table 4).

The mean fasting blood sugar (162.4 ± 32.6 mg/dL) and postprandial blood sugar (232.7 ± 46.1 mg/dL) were markedly elevated compared to normal reference ranges, indicating poor short-term glycemic control among participants. The mean HbA1c level was 8.7 ± 1.4%, reflecting chronic hyperglycemia over the preceding 2–3 months. These findings suggest inadequate metabolic control, which is strongly associated with the development and progression of diabetic retinopathy (Figure 2).

Table 5: Renal and Lipid Profile of Study Participants (n = 50)

The mean serum creatinine level (1.2 ± 0.4 mg/dL) was near the upper normal limit, with 48% of participants showing positive urine albumin, indicating early diabetic nephropathy. Lipid profile abnormalities were common: total cholesterol and triglycerides were close to or above upper normal limits, and HDL was below the recommended threshold, especially in men. Elevated LDL (116.4 ± 28.9 mg/dL) further suggests atherogenic risk. These metabolic disturbances may contribute to retinal vascular damage and worsening of diabetic retinopathy (Table 5).

Table 6: Association between Risk Factors and Severity of Diabetic Retinopathy (n = 50)

            Note: *p < 0.05 = significant, *p < 0.01 = highly significant

A statistically significant association was observed between the severity of diabetic retinopathy and multiple risk factors. Patients with a diabetes duration ≥10 years had a significantly higher rate of severe NPDR and PDR (73.9%, p = 0.002). Similarly, poor glycemic control (HbA1c ≥8%) was strongly associated with severe retinopathy (78.3%, p = 0.005). Hypertension was significantly more prevalent in the severe DR group (73.9%, p = 0.023), highlighting its role in disease progression. Nephropathy also showed a strong association with DR severity (47.8% in severe group, p = 0.004), suggesting systemic microvascular involvement. These findings emphasize the impact of long-standing diabetes, poor metabolic control, and systemic comorbidities on the progression of retinopathy (Table 6).

Table 7: Pearson’s Correlation between DR Severity and Continuous Risk Factors (n = 50)

                                             Note: *p < 0.05 = significant, *p < 0.01 = highly significant

Pearson’s correlation analysis revealed a strong positive correlation between diabetic retinopathy severity and duration of diabetes (r = +0.62) as well as HbA1c levels (r = +0.59), both statistically highly significant (p < 0.001). Moderate positive correlations were also noted with fasting blood sugar (r = +0.44), postprandial blood sugar (r = +0.41), and serum creatinine (r = +0.47), indicating that poor glycemic control and declining renal function are associated with more severe stages of retinopathy. These findings highlight the cumulative effect of chronic hyperglycemia and systemic metabolic dysfunction on retinal microvascular damage (Table

Diabetic retinopathy (DR) remains one of the most frequent and serious microvascular complications of diabetes mellitus, particularly in long-standing and poorly controlled cases. In this study conducted at Mamata Medical College, Khammam, we investigated the clinical, biochemical, and systemic risk factors associated with the severity of diabetic retinopathy among 50 patients.

The mean age of the patients was 56.8 ± 9.4 years, and there was a slight male preponderance (60%), which is comparable to the findings by Mohan and Pradeepa (2009), who also reported a higher incidence in males likely due to greater healthcare access (6). The mean duration of diabetes was 10.2 ± 4.6 years. Our findings demonstrated a statistically significant association between longer duration of diabetes and greater severity of DR (p = 0.002). This aligns with the results of Yau et al. (2012) and the Wisconsin Epidemiologic Study of Diabetic Retinopathy (7), both of which confirm duration as a major risk factor for disease progression.

Glycemic parameters were notably elevated in our cohort, with a mean HbA1c of 8.7 ± 1.4%, FBS of 162.4 ± 32.6 mg/dL, and PPBS of 232.7 ± 46.1 mg/dL. A moderate positive correlation was observed between HbA1c and DR severity (r = 0.59, p < 0.001), reinforcing the findings from the DCCT (1993) and UKPDS (1998), which established that tight glycemic control significantly reduces the risk of DR progression (8, 9). Similar correlations were found in studies by Roy et al. (2013), suggesting that both fasting and postprandial glucose contribute to cumulative vascular damage (10).

In our study, hypertension was present in 56% of the patients and showed a significant association with DR severity (p = 0.023). This supports the findings of Chew et al. (1996), who noted that elevated blood pressure worsens retinal microvascular damage (11). Additionally, 28% of our patients had nephropathy, and a strong association was found with severe retinopathy (p = 0.004), which is consistent with findings by Rani et al. (2008) and the Chennai Urban Rural Epidemiology Study (CURES Eye Study).

Dyslipidemia was seen in 40% of the patients, and although not statistically analyzed in depth in this study, previous literature by Klein et al. (1995) has demonstrated that elevated serum lipids, particularly triglycerides and LDL, contribute to hard exudate formation and macular edema.

The most common presenting symptom was blurring of vision (76%), followed by floaters (24%) and visual field changes (12%). These are in line with clinical patterns described in Indian hospital-based studies. On fundus examination, moderate NPDR was the most common stage (34%), while 22% had PDR, indicating a significant burden of advanced disease. Macular edema was observed in 28% of eyes, a finding consistent with Pradeepa et al. (2008), where diabetic macular edema was reported in 23%–30% of patients with DR.

Serum creatinine also showed a moderate correlation with DR severity (r = 0.47, p = 0.001), further reinforcing the interconnectedness of diabetic microvascular complications across different organ systems.

This study confirms that longer duration of diabetes, poor glycemic control (HbA1c ≥8%), hypertension, and diabetic nephropathy are significantly associated with the severity of diabetic retinopathy. A moderate to strong positive correlation exists between DR severity and these risk factors, emphasizing the need for strict glycemic and blood pressure control to prevent or delay the progression of sight-threatening diabetic retinopathy.

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