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This study aims to fill this gap by conducting a cross-sectional and analytical investigation within the ophthalmology departments of Garoua General Hospital and Garoua Regional Hospital. By focusing on type 2 diabetic patients, we endeavor to elucidate the factors contributing to the presence of DR in our local context over a period of 1 year from January 3rd, 2023 to January 15th, 2024. Demographic data (age, sex, and profession) and clinical information were collected. Ocular examinations included measurement of visual acuity, slit lamp examination, and fundus examination. Additional tests, such as macular optical coherence tomography and ocular ultrasound, were conducted when necessary. Diagnosed ocular pathologies were documented. The mean age of our patients is 53.9 years with a standard deviation of 13.2 years. Notably, there is a predominant representation of females. Regarding ocular health, 8.8% of patient exhibit blindness. The prevalence of diabetic retinopathy (DR) in our cohort is 24.5% with a 95% confidence interval ranging from 16.16 to 32.86%. It is noteworthy that all patients diagnosed with DR have a glycated hemoglobin level exceeding 7%. We have observed a prevalent occurrence of diabetic retinopathy within our community. Notably, all individuals diagnosed with diabetic retinopathy exhibit abnormal levels of glycated hemoglobin.
Faculty of Medicine and Biomedicals Sciences, Garoua University, Cameroon
Balkissou Adamou Dodo
Faculty of Medicine and Biomedicals Sciences, Garoua University, Cameroon
Inna Hadja
Faculty of Medicine and Biomedicals Sciences, Garoua University, Cameroon
Patrice Esame
Garoua Regional Hospital Center, Cameroon
Godefroy Koki
Faculty of Medicine and Biomedicals Sciences, Yaoundé 1 University, Cameroon
*Address all correspondence to: marenjoya@gmail.com
1. Introduction
Diabetes constitutes a significant and escalating public health concern worldwide, affecting an estimated 463 million individuals globally, with over 19 million cases recorded in Africa alone [1]. Remarkably, this number is projected to surge to 55 million by 2045, marking a 34% increase from 2021 figures [2]. Of grave concern is that a substantial portion of affected individuals remain undiagnosed, with an estimated 70% unaware of their diabetic status [2]. Type 2 diabetes, predominant in developing nations, has undergone a notable rise across Africa since 1980, with prevalence rates escalating in various regions. For instance, Tanzania witnessed an increase from 2.3% in 1980 to 4.6% in 1996, while in Central Africa, prevalence rates soared to 7.1% in Guinea, 10.2% in Zimbabwe, and 14.5% in the Democratic Republic of Congo. The Maghreb region has also experienced a surge, with prevalence rates recorded at 10% in Tunisia, 9.3% in Egypt, and 8.1% in Morocco [2].
The ocular complication of diabetes, known as diabetic retinopathy (DR), stems from elevated blood sugar levels, instigating a cascade of biochemical and histological changes in the retina [3]. These changes, including thickening of capillary basal membranes and subsequent breakdown of the blood-retinal barrier, culminate in severe visual impairments, including macular edema and neovascularization, leading to blindness [4].
In Africa, the burden of DR is palpable, with prevalence rates varying across countries. Abouki Coa and al in Cotonou reported a prevalence of 30.5% in 2019 [3], whereas recent studies in Cameroon documented frequencies ranging from 12.3 to 45.5% [4, 5]. Identifying risk factors associated with DR is crucial for effective management and prevention strategies. A meta-analysis conducted by Jie Xuan et al. in 2022 outlined several risk factors, including the duration of diabetes, systolic blood pressure, body mass index, HbA1c levels, and lipid profile abnormalities [6]. In the world and specially in Morocco there are underscored associations between DR and chronic hyperglycemia, arterial hypertension, dyslipidemia, and diabetic neuropathy [7, 8].
Despite the pressing need for comprehensive studies on DR risk factors in Africa, limited research exists, particularly in countries, such as Cameroon. Thus, this study aims to fill this gap by conducting a cross-sectional and analytical investigation within the ophthalmology departments of Garoua General Hospital and Garoua Regional Hospital. By focusing on type 2 diabetic patients within these centers, we endeavor to elucidate the factors, contributing to the presence of DR in our local context.
A cross-sectional and analytical study over a period of 1 year from January 3rd, 2023 to January 15th, 2024 was conducted in the main two hospitals unit in Garoua-North Cameroon:
The Garoua General Hospital, a collaborative effort between Cameroon and South Korea, which has swiftly become a vital healthcare hub, caters to a diverse patient base hailing from Garoua and beyond, including various localities in northern Cameroon, as well as neighboring regions in TChad and Nigeria [9]. The hospital hosts a noteworthy department. The department is equipped with advanced diagnostic and surgical capabilities and attends to approximately 60 patients each month; it offers a range of services, including consultations, eye surgeries, and diagnostic procedures such as perimetry, ocular ultrasound, and retinal angiography.
The Garoua Regional Hospital
With an average monthly patient load of around 3000 individuals, the Garoua Regional Hospital received 4990 ophthalmology consultations in 2023 alone. Among the most prevalent conditions treated were ametropia, allergic conjunctivitis, cataracts, infectious conjunctivitis, glaucoma, pterygium, and corneal ulcerations, indicative of the diverse range of eye health issues addressed by the hospital. Within a hospital, there exists a diabetes clinic housed at the voluntary prevention and screening Center (VPSC).
2.1 Procedure
Following administrative and ethical approvals, the study included all type 2 diabetic patients who consented to participate and received care at the ophthalmology departments of Garoua General Hospital (GGH) and Garoua Regional Hospital (GRH) during the study period. Patients with complete data available were included, while those who did not consent or had incomplete information were excluded.
Using an anonymous technical form, demographic data (age, sex, and profession) and clinical information were collected. This included general cardiovascular history (such as dyslipidemia, nephropathy, heart disease, hyperuricemia, obesity/overweight, and hypertension), duration of diabetes, prescribed antidiabetic treatment, treatment compliance, reasons for noncompliance if applicable, and diabetes-related complications (including infections, ketoacidosis, polyneuropathy, kidney damage, diabetic foot, retinopathy, cardiopathy, and stroke).
Therapeutic compliance was assessed using the French-translated Morisky Green questionnaire, with a score below six indicating poor compliance. Obesity was defined as a body mass index (BMI) of 30 or above and overweight as a BMI greater than 25.
Ocular examinations included measurement of corrected distance visual acuity, slit lamp examination, and fundus examination using a 90-diopter Volk lens. Additional tests, such as macular optical coherence tomography and ocular ultrasound, were conducted when necessary. Diagnosed ocular pathologies were documented, including cataracts, glaucoma, ametropia, and diabetic retinopathy (DR). They were classified according to the simplified Alfediam classification, which distinguishes between no diabetic retinopathy, non-proliferative DR (with varying severity), and proliferative DR (with varying severity and complications). Diabetic maculopathy was classified as either edematous or ischemic.
This study aimed to comprehensively assess the ocular health of diabetic patients and their adherence to treatment protocols, providing valuable insights for their management and care.
2.2 Sample size
We determined the minimum sample size using OpenEpi software version 3 (revised April 2013). Considering the combined active queues of type 1 and type 2 diabetic patients at GGH (200 patients) and VPSC of GRH (603 patients), our study population was estimated at 803 patients in 2023. Based on a 90% confidence interval and a diabetic retinopathy prevalence of 12.3% in Cameroon according to Bediang et al. [10], the minimum sample size was calculated to be 101 patients.
2.3 Statistical analyses
Data were analyzed using IBM SPSS Statistics for Windows, Version 23 (IBM Corp., Armonk, New York, United States, 2015). Quantitative variables were presented as means and standard deviations, while qualitative variables were expressed as counts and percentages. Univariate analysis was utilized to assess the association between qualitative variables (such as age, sex, duration of diabetes, type of treatment, therapeutic compliance, and cardiovascular pathologies) and the presence of diabetic retinopathy (DR) observed during fundus examinations. The chi-square test was employed for comparing qualitative variables, while quantitative variables were compared using either the Student’s t-test or the Mann-Whitney U test for non-parametric data. Variables found to be associated with DR in univariate analysis were included in a logistic regression model to identify independent factors associated with DR. A significance threshold of 5% was applied.
In total, we examined 102 type 2 diabetic patients or 204 eyes.
3.1 Sociodemographic data
The mean age was 53.9 ± 13.2 years with a minimum age of 30 years and a maximum of 90 years. We had 59(57.8%) women and 43(42.2%) men for a sex ratio of 1.4 in favor of women (Figure 1).
Figure 1.
Distribution of patients according to their profession.
The prevalence of diabetic retinopathy in our setting was 24.5 95% CI [16.16;32.86].
The average duration of diabetes in our patients was 6.8± 6.1 years with (33) 32.4% of patients having a history of diabetes for more than 10 years (Figures 4 and 5).
The compliance to treatment was found in 62 (60.8%) patients (Figures 6 and 7).
Overweight or obesity was found in 45(44.1%) patients.
Glycated hemoglobin greater than 7% was found in 83 (81.4%) patients (Table 3).
Figure 2.
Distribution of ocular pathologies diagnosed in type 2 diabetic patients.
Figure 3.
Distribution of results of fundus examination of the right eye. NPDR ₌ non-proliferative diabetic retinopathy, IVH=IntraVitreal hemorrhage, DR = diabetic retinopathy.
Visualacuityof right eye
Effective n
Percentage %
No light perception
1
1
Light perception
2
2
<1/10
6
5.9
<5/10
41
40.2
5/10–8/10
40
39.2
>8/10
12
11.7
Total
102
100
Table 1.
Distribution of patients according to the visual acuity of the right eye.
Visual acuity of left eye
Effective n
Percentage %
No light perception
2
2
Light perception
3
2.9
<1/10
3
2.9
<5/10
41
40.2
5/10–8/10
40
39.2
>8/10
13
12.8
Table 2.
Distribution of patients according to the visual acuity of the left eye.
Figure 4.
Distribution of results of fundus examination of the left eye. NPDR = non-proliferative diabetic retinopathy, PVD=posterior vitreous detachment, DR = diabetic retinopathy.
Figure 5.
Distribution of the type of treatment taken by patients.
Figure 6.
Reasons for noncompliance to treatment.
Figure 7.
Distribution of metabolic disorders among our patients.
Associated factors
Diabetic retinopathy
Total
p value
Present
Absent
28
0.3
Duration of Diabetes equal or more than 10 years
YES
5
23
NO
20
54
74
Therapeutic Compliance
YES
14
48
62
0.6
NO
11
29
40
Metabolic disorders
YES
18
41
59
0.09
NO
7
36
43
Neuropathy
YES
9
23
32
0.6
NO
16
54
70
Nephropathy
YES
3
6
9
1.0
NO
23
71
94
Glycate hemoglobin superior to 7%
YES
25
58
83
0.001
NO
0
19
19
Table 3.
Cross table showing associated factors with diabetic retinopathy.
The factor, which seems to influence the occurrence of diabetic retinopathy in our patients, seems to be the glycated hemoglobin level greater than 7%. (p < 0.05).
Several key findings are presented in this study. Firstly, the mean age of our patients is 53.9 years with a standard deviation of 13.2 years. Notably, there is a predominant representation of females, accounting for 57.8% of the study population compared to 42.2% of males. On average, our patients have been living with diabetes for 6.8 years, with 27.5% of them having a disease duration exceeding 10 years. Regarding ocular health, 12.7% of patients exhibit blindness, while pathologies, such as cataracts and glaucoma, which can potentially lead to blindness, are present in 43.1% of cases. The prevalence of diabetic retinopathy (DR) in our cohort is 24.5% with a 95% confidence interval ranging from 16.16% to 32.86%. It is noteworthy that all patients diagnosed with DR have a glycated hemoglobin level exceeding 7%. Moreover, adherence to treatment measures is observed in 56% of patients. Metabolic syndrome is prevalent in 72% of those diagnosed with DR, indicating a significant comorbidity. Additionally, neuropathy is identified in 36% of patients presenting with DR, while nephropathy is present in 8% of cases. These findings underscore the multifaceted nature of diabetes and its associated complications within our patient population.
4.1 Characteristics of the study population
The demographic profile of the study population mirrors findings from Bediang et al. [10] conducted in Yaoundé, Central Cameroon, where the mean age was 53.5 ± 14.7 years, with females constituting 56.9% of participants [11]. Similarly, in our study conducted in North Cameroon, the mean age was 53.9 ± 13.2 years, with 57.8% being female. This trend of female predominance is also observed in Cotonou, as evidenced by Abouki C et al., who reported a sex ratio of 0.57 in favor of women [3]. Conversely, an Ethiopian study on 331 diabetic patients reported a slightly lower mean age of 45.48 (SD ± 16.88) years, with men comprising around 54.7% of the participants [12].
4.2 Clinical data
The prevalence of diabetic retinopathy in our study stands at 24.5%, slightly higher than the 12.3% reported by Bediang et al. in Yaoundé but lower than the 34.1% found in Ethiopia [13]. The variation in prevalence rates may be attributed to differences in sample sizes and methodologies employed. Notably, a French study highlights diabetic retinopathy as the leading cause of low vision in individuals under 50 years old, with affluent populations experiencing a decreasing trend in prevalence due to advancements in screening, diagnostics, and therapeutic interventions, including intravitreal pharmacological treatments [14].
In our community, all patients diagnosed with diabetic retinopathy have a glycated hemoglobin level exceeding 7%, with 81.4% exhibiting poorly controlled diabetes. Nonadherence to treatment is observed in 39.2% of patients, often attributed to financial constraints, forgetfulness, treatment fatigue, and the use of traditional African remedies. Studies conducted in Cameroon emphasize the necessity of implementing effective management strategies for diabetes and its complications, highlighting low awareness levels and inappropriate attitudes toward disease prevention among diabetic patients [15, 16]. In China, the prevalence of diabetic retinopathy is about 9.9% [10]. Patients who have diabetic retinopathy in our community all have a glycated hemoglobin level greater than 7%. In addition, 81.4% of patients in our study have poorly controlled diabetes. Nonadherence is observed in 39.2% of patients. This noncompliance can be explained by the lack of financial means, forgetfulness, fatigue in taking the treatment, and the use of the plants of the African pharmacopeia. Cameroonian study to evaluate systems and services for the management of diabetes and diabetic retinopathy shows that a suitable implementation strategy is necessary in our context [4]. Abah Abah shows in 2023 concerning diabetic patients followed at the diabetic clinic in the center region of Cameroon that diabetic patients have a poor level of awareness and a non-appropriated attitude toward preventing the outcome of disease complications [5].
Regarding associated factors, our study identifies a high glycated hemoglobin level (>7%) as the sole independent determinant of diabetic retinopathy. However, studies conducted elsewhere reveal additional determinants such as poor medication adherence, older age, illiteracy, high systolic blood pressure, family history of diabetes, other microvascular complications, poor glycemic and cholesterol control, anemia, arterial hypertension, dyslipidemia, diabetes imbalance, and prolonged disease duration [17, 18, 19, 20]. On a slightly larger sample, Ouazzani and al in Morocco add as another associated factor the imbalance of diabetes. In South Africa, Mjwara shows that proliferative diabetic retinopathy is associated with higher HbA1c in type 2 diabetes mellitus in all races and age groups and was independent of duration of disease [6, 12]. In 2019, a study conducted in Benin revealed that the presence of long-standing nephropathy, glycated hemoglobin, age of discovery of diabetes, and its duration were the factors associated with diabetic retinopathy [3]. Ahmadou et al. in 2014 in a large sample of 408 patients with 88% of type 2 patients noticed a strong correlation between the duration of diabetes and retinopathy status (p < 0.001, r = 0.9541) [6].
Burgees PI et al. about DR in sub-Saharan African patients said poor glycemic and blood pressure control lead to rapid progression of DR [14].
The limitations of our study are the small number of our patients.
In summary, we have observed a prevalent occurrence of diabetic retinopathy within our community. Notably, all individuals diagnosed with diabetic retinopathy exhibit abnormal levels of glycated hemoglobin. The issue of therapeutic adherence emerges as a critical concern in the management of diabetes, often stemming from financial constraints, limited awareness, misconceptions about the disease, and the burden of chronic medication intake.
Therefore, we recommend the following actions:
To healthcare facilities: It is imperative to institute counseling initiatives and incorporate counseling and psychological support into healthcare professionals’ training programs. This approach aims to enhance patient adherence to treatment regimens.
To the Ministry of Public Health: Efforts should be directed toward enhancing patient access to endocrinologists and antidiabetic medications. This can be achieved through the establishment of subsidized pathways to ensure the affordability and availability of essential drugs.
To the Ministry of Scientific Research: Encourage and financially support research endeavors focusing on diabetes, particularly exploring the potential of African pharmacopoeia derived from plants. This avenue is of interest as some patients within our community express a preference for traditional remedies over conventional medications. Such research could lead to the development of effective treatments aligned with local preferences and practices.
The author wishes to thank their dear family for the support and all co-authors of this study for their contributions. The author would also like to thank Dr. Aminou Mohamadou for proofreading the manuscript. The author is grateful to all the patients, who consented to participate, and all the staff of the ophthalmology department of the health facilities.
All authors of this work do not declare any conflicts of interest.
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Written By
Josiane Mare Njoya, Balkissou Adamou Dodo, Inna Hadja, Patrice Esame and Godefroy Koki
Submitted: 31 January 2024Reviewed: 23 April 2024Published: 04 June 2024
Open access peer-reviewed chapter - ONLINE FIRST
