Abstract
Purpose:
The study was conducted to compare the compliance to intravitreal injection treatment and follow-up in patients with center-involving diabetic macular edema (CI-DME) and treatment outcomes between a tertiary eye care facility and a tertiary diabetes care center.
Methods:
A retrospective review was conducted on treatment naïve DME patients who had received intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections in 2019. Participants were people with type 2 diabetes who were under regular care at the eye care center or the diabetes care center in Chennai. The outcome measures were noted at months 1, 2, 3, 6, and 12.
Results:
A review of 136 patients treated for CI-DME (72 from the eye care center and 64 from a diabetes care center) was carried out. The severity of diabetic retinopathy (DR) was similar in both centers. There was no statistically significant (P > 0.05) difference in the choice of initial intravitreal drug in the two centers. At 12-month follow-up, only 29.16% came for a follow-up in the eye center vs. 76.56% in a diabetes care center (P = 0.000). The multivariate logistic regression showed increasing age was associated with non-compliance in both the groups (eye care center: odds ratio [OR] 0.91; 95% confidence interval [CI] 0.82–1.21; P = 0.044) and diabetes care center (OR 1.15; 95% CI 1.02–1.29; P = 0.020).
Conclusion:
The follow-up rate between eye care and diabetic care center with DME showed a significant disparity. By providing comprehensive diabetes care for all complications under one roof, compliance with follow-up can be improved in people with DME.
Keywords: Compliance, diabetes care center, eye care center, diabetic macular edema, intravitreal injections
A successful outcome in any treatment plan includes timely intervention and regular patient follow-up. Treatment failure can be due to delayed follow-up or non-compliance and non-adherence to the treatment plan. There is evidence that the success of treating diabetic macular edema (DME) is related to patients’ compliance to come for review for monthly check-ups and/or intravitreal injections as advised.[1,2,3]
We had earlier reported findings of the framework analytical approach to understanding the barriers to diabetic retinopathy (DR) screening.[4] We found that patients with diabetes are often aware of diabetes, but knowledge regarding DR and its complications is poor.[4] The absence of symptoms, difficulties in doctor–patient interactions, and the tedious nature of follow-up care were some major deterrents to care-seeking by patients.
Intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy is the recommended first-line treatment for center-involving diabetic macular edema (CI-DME). Sucheta et al. reported the visual and anatomical outcomes following treatment for DME in multiple eye hospitals in India.[5] They found that most eyes (80%) received three or fewer intravitreal injections during 1 year. The mean number of injections was 2.1, far less than those recommended by international guidelines.[5]
Studies in urban and rural India have shown reasonably good compliance with anti-diabetic medications.[6,7] The compliance was better with an increase in the duration of diabetes. Most micro and macrovascular complications of diabetes are often managed by a physician/diabetologist. They are usually cross-referred to a specialist such as a neurologist or a nephrologist in the more severe stage of these complications when specialized interventions are required.
Similarly, in vision-threatening DME, the physician often refers the patient to an ophthalmologist for appropriate treatment and care. Very few diabetes care centers have in-house ophthalmologists to manage DME. It is unknown whether providing comprehensive diabetes care for all complications, including DR, under one roof and whether the compliance and outcome of treatment of DME can be better than the care at an eye care facility. Our study aimed to compare patient adherence to intravitreal injection treatment and follow-up in patients with CI-DME and treatment outcomes between eye care and diabetes care centers.
Methods
Participants in this study were people with type 2 diabetes who were under regular care at either a tertiary eye care center or a tertiary diabetes care center in Chennai, South India. The diabetes care clinic has full-time in-house ophthalmologists with vitreoretinal services to provide knowledge and treatment. The diabetologist sends patients who report to the diabetes care center to the retina department, where retinal images are taken following mydriasis. A retinal expert is available for immediate or future management.
A retrospective review was conducted on treatment-naive DME patients who received anti-VEGF injections between July 2019 and August 2019. Data were collected from both centers’ structured electronic databases of patients with DME. This study was conducted following the tenets of the Declaration of Helsinki, and ethical approval was obtained from the Institutional Review Board. Patients with type 2 diabetes who underwent treatment for CI-DME and were residents of Chennai city, South India, where both hospitals were located, were included in the study. Exclusion criteria included high myopia (> 8 diopters), glaucoma, media opacities due to cataract or corneal disease, history of ocular trauma, and poor-quality spectral-domain optical coherence tomography (SD-OCT) images. The details of demographic and other systemic diseases, previous follow-up visits, any previous ocular surgeries, the severity of DR, and initial treatment at baseline were noted. The outcome measures were reported at months 1, 2, 3, 6, and 12. These included the percentage of patients who came for these follow-up visits, the status of DME (improved/stable and worsened), the number of intravitreal injections given, and the patients in whom the switch to another intravitreal anti-VEGF or steroids was performed. The treating ophthalmologist judged the status of DME based on central subfield foveal thickness; <10% reduction on follow-up compared to the baseline was considered worsening.
Statistical analysis
All statistical tests were performed using SPSS, version 18. For descriptive statistics, categorical data are presented as frequencies and percentages, n (%); ordinal, discrete, and continuous data are shown as means with accompanying standard deviations (SDs). To compare characteristics between the two groups, an independent t-test and c2 test were used to compare means and proportions, respectively. The difference in variables between categorical factors was assessed using a Chi-square test. Stepwise regression analysis was used to determine the predictive factors for poor compliance. A P value of <0.05 was considered statistically significant for all statistical tests.
Results
We assessed the follow-up data of 136 patients who underwent treatment for DME, 72 from the eye care center, and 64 individuals from the diabetes care center during the study period. Table 1 shows the baseline characteristics of patients from two centers. Patients from the diabetes care center had a longer duration of diabetes, higher diastolic BP, and more patients with dyslipidemia, a history of cardiac illness, and diabetic neuropathy (P < 0.05). The eye care center had more patients who had free consultations and treatment.
Table 1.
Baseline characteristics of individuals with diabetic macular edema treated at the eye care center and diabetic care centre
| Variables | Eye care center (n=72) | Diabetes care center (n=64) | P |
|---|---|---|---|
| Age (mean±SD) in years | 60.78+7.94 | 58.58±9.87 | 0.153 |
| Gender n (%) | 0.09 | ||
| Men | 56 (77.77%) | 41 (65.06%) | |
| Women | 16 (22.22%) | 23 (35.93%) | |
| Duration of diabetes in years | 15.69±8.20 | 18.95±6.66 | 0.013 |
| Blood pressure (mm Hg) | 0.569 | ||
| Systolic | 139.26±16.57 | 140.66±10.90 | |
| Diastolic | 75.26±8.94 | 86.91±8.08 | 0 |
| Systemic illness n (%) | 0.339 | ||
| Hypertension | 49 (68.05%) | 49 (76.56%) | |
| Dyslipidemia | 15 (20.83%) | 48 (75.0%) | 0 |
| History of cardiac illness | 11 (15.27%) | 21 (32.81%) | 0.025 |
| Diabetic neuropathy | 2 (2.77%) | 8 (12.50%) | 0.046 |
| Diabetic nephropathy | 6 (8.33%) | 11 (17.18%) | 0.13 |
| Payment for consultation and treatment n (%) | 0.001 | ||
| Non-paying patient | 16 (22.22%) | 2 (3.12%) | |
| Paying patients | 56 (77.77%) | 62 (96.87%) |
Table 2 shows the DME characteristics and treatment in the two centers at the baseline. The diabetes care center had more patients already on a follow-up than the eye care center (73.43% vs. 56.94%, P = 0.05). Among the patients on follow-up, the diabetes care center had patients for a longer previous duration on follow-up than the eye care center (7.87 + 4.24 years vs. 2.82 + 3.08 years, P = 0.000). The severity of DR was similar in both centers. There was no statistically significant difference in the choice of initial anti-VEGF agent in the two centers. Patients with vision <0.6 were more common in the diabetes care center (59, 92.18%) than in the eye care center (55, 76.38%). During the follow-up visits, the mean number of injections was 3.44 + 2.92 in the eye care center and 4.46 + 2.26 in the diabetes care center, which is statistically significant (P = 0.025).
Table 2.
DME characteristics at baseline
| Variables | Eye care center (n=72) | Diabetic care center (n=64) | P | |
|---|---|---|---|---|
| Previous visit status | Number of new patients | 31 (43.05%) | 17 (26.56%) | 0.050 |
| Number of follow-up patients | 41 (56.94%) | 47 (73.43%) | ||
| Follow-up patients | Mean duration of follow-up patients in years | 2.82±3.08 | 7.87±4.24 | 0.000 |
| History of previous ocular surgery | Cataract surgery | 33 (45.83%) | 21 (32.81%) | 1.000 |
| Vitreous surgery | 2 (2.77%) | 2 (3.12%) | ||
| Severity of DR | NPDR with DME | 46 (63.88%) | 41 (64.06%) | 1.000 |
| PDR with DME | 26 (36.11%) | 23 (35.93%) | ||
| Preference for intravitreal therapy | Preference of innovator molecules | 24 (33.3%) | 26 (40.6%) | 0.378 |
| Biosimilars and off-label molecules | 48 (66.7%) | 38 (59.4%) | ||
| Visual acuity | ≤0.6 | 55 (76.38%) | 59 (92.18%) | 0.018 |
| (logMAR) | >0.6 | 17 (23.61%) | 5 (7.81%) | |
| The mean number of injections | 3.44±2.92 | 4.46±2.26 | 0.025 | |
*NPDR: Non-proliferative diabetic retinopathy, †PDR: Proliferative diabetic retinopathy, ‡DR: Diabetic retinopathy, **DME: Diabetic macular edema
The compliance of patients’ visits was better in the diabetes care center compared to the eye care center at all the follow-ups; 1, 2, 3, 6, and 12 months (P < 0.05) as shown in Fig. 1. At 12 months follow-up, only 29.16% in an eye center came for a follow-up vs. 76.56% in a diabetes care center (P = 0.000). There were more non-paying patients in the eye care center than in the diabetes care center. The drop-out rate at an eye care center revealed that the early stage of the disease, 64.30% (NPDR with DME) was more than the proliferative stage, 35.70% (PDR with DME) in the non-paying group.
Figure 1.
Comparison of follow up after intravitreal injection for center involving diabetic macular edema at the eye care and diabetic care center
Except for months 1 and 2, at all other follow-up visits, there was no statistically significant difference in the DME status in the eye care center as compared to the diabetes care center. There was no statistically significant difference between the groups in switching to another anti-VEGF or steroid pattern. At the 1-year follow-up visit, there was no difference in the DME outcome between the two groups. Patients at the diabetes care center only underwent additional macular lasers during the follow up visits and the details were discussed in Table 3.
Table 3.
DME characteristics on follow-up visits
| Variables | Eye care center (n=72) | Diabetes care center (n=64) | P | ||
|---|---|---|---|---|---|
| 1-month follow-up | DME status | Improved/stable | 44 (70.97%) | 57 (89.06%) | 0.008 |
| Worsened | 18 (29.03%) | 7 (10.93%) | 0.011 | ||
| Switched to other anti-VEGFs | - | 2 (3.12%) | - | ||
| Switched to steroids | 2 (3.22%) | 2 (3.12%) | 0.974 | ||
| Additional macular laser | - | 21 (32.81%) | - | ||
| 2nd-month follow-up | DME status | Improved/stable | 36 (81.82%) | 27 (50.0%) | 0.001 |
| Worsened | 8 (18.18%) | 27 (50.0%) | 0.058 | ||
| Switched to other anti-VEGF | - | 4 (7.40%) | - | ||
| Switched to steroids | 1 (2.27%) | - | |||
| Additional macular laser | - | 10 (18.51%) | - | ||
| 3rd-month follow-up | DME status | Improved/stable | 34 (89.47%) | 35 (74.47%) | 0.079 |
| Worsened | 4 (10.52%) | 12 (25.53%) | 0.080 | ||
| Switched to other anti-VEGFs | 1 (2.63%) | - | |||
| Switched between injections and steroids | 1 (2.63%) | 2 (4.25%) | 0.687 | ||
| Additional macular laser | - | 1 (2.12%) | - | ||
| 6th-month follow-up | DME status | Improved/stable | 20 (80.00%) | 29 (61.70%) | 0.106 |
| Worsened | 5 (20.00%) | 18 (38.30%) | 0.002 | ||
| Switched to other anti-VEGFs | 1 (4.00%) | - | - | ||
| Switched to steroids | 2 (8.00%) | - | - | ||
| Additional macular laser | - | 3 (6.38%) | - | ||
| 1-year follow-up | DME status | Improved/stable | 18 (85.72%) | 36 (73.47%) | 0.267 |
| Worsened | 3 (14.28%) | 13 (26.53%) | 0.266 | ||
| Switched to other anti-VEGFs | 1 (4.76%) | - | - | ||
| Switched to steroids | 2 (9.552%) | 1 (2.04%) | 0.158 | ||
| Additional macular laser | - | 1 (2.04%) | - | ||
Table 4 shows the multivariate logistic regression analysis to analyze the risk factors for non-compliance with follow-up visits. Increasing age was a risk factor associated with non-compliance in both the groups (eye care center: odds ratio [OR] 0.91 95% confidence interval [CI] 0.82–1.21, P = 0.044) and diabetes care center (OR 1.15 [95%CI 1.02–1.29], P = 0.020). Likewise, the initial preference for innovator molecules intravitreal therapy was a risk factor for non-compliance in the diabetes care center (OR 2.16 [95%CI 1.03–3.97], P = 0.042). In the eye care center, treatment with innovator molecule intravitreal therapy showed twice greater odds associated with non-compliance, although not statistically significant (OR 1.48 [95%CI 0.35–2.45], P = 0.083). The history of other systemic comorbidities was a risk factor associated with non-compliance in the eye care center (OR 1.64 [95%CI 1.14–2.84], P = 0.035) but not seen in the diabetes care center (OR 1.89 [95%CI 0.34–4.20], P = 0.466).
Table 4.
Multivariate logistic regression analysis to assess the risk factors associated with non-compliance to follow-up in individuals with center involving diabetic macular edema
| Variables | Eye care center (n=72) | Diabetic care center (n=64) | ||||
|---|---|---|---|---|---|---|
|
|
|
|||||
| Odds | 95% CI | P | Odds | 95% CI | P | |
| Age (per year increase) | 0.91 | (0.82–1.21) | 0.044 | 1.15 | (1.02–1.29) | 0.020 |
| Women (ref: men) | 1.5 | (0.37–6.08) | 0.564 | 1.54 | (1.08–2.01) | 0.450 |
| Duration of diabetes (per year increase) | 1.09 | (1.00–1.20) | 0.047 | 0.91 | (0.78–1.06) | 0.261 |
| History of other systemic illness (ref: no other systemic illness) | 1.64 | (1.14–2.84) | 0.035 | 1.89 | (0.34–4.20) | 0.466 |
| Innovator molecule intravitreal drugs (ref: biosimilars and off-label molecules)* | 1.48 | (0.35–2.45) | 0.083 | 2.16 | (1.03–3.97) | 0.042 |
| PDR with DME (ref: NPDR with DME) | 0.53 | (0.08–1.45) | 0.339 | 2.79 | (1.33–3.42) | 0.344 |
| Paying patient (ref: non-paying patient) | 0.18 | (0.02–1.12) | 0.066 | 0.24 | (0.08–3.54) | 0.245 |
| New patient (ref: those who had previous visits) | 0.63 | (0.17–2.38) | 0.504 | 2.03 | (0.31–3.98) | 0.452 |
| Visual acuity (ref: ≤0.6) | 0.58 | (0.11–2.42) | 0.419 | 1.03 | (0.03–5.32) | 0.839 |
| The mean number of injections over 1 year (ref :<3 injections) | 3.24 | (0.91–5.48) | 0.054 | 1.19 | (0.38–2.15) | 0.040 |
*NPDR: Non-proliferative diabetic retinopathy, †PDR: Proliferative diabetic retinopathy, ‡DR: Diabetic retinopathy, **DME: Diabetic macular edema. Innovator molecule intravitreal drugs: ranibizumab and dexamethasone implant, Biosimilars and off label molecules: bevacizumab, biosimilar of ranibizumab, and triamcinolone
Discussion
Adherence to follow-up advice is essential to achieve desired benefits from any treatment, which is especially important for managing DME. Individuals receiving intravitreal anti-VEGF injections are expected to comply with follow-up OCT and receive the next intravitreal injection based on ophthalmologist advice. The present study showed a significant disparity in the follow-up rate between individuals with DME treated with anti-VEGF therapy at the eye care and diabetes care centers. Only 29.16% in an eye clinic vs. 76.56% in a diabetes care clinic came for a follow-up at 1 year.
We found no difference in the DME outcome between the two groups. Increasing age was associated with poor compliance in both groups. The cost of treatment was associated with poor compliance in the diabetes care center. In a country such as India, most patients pay out of pocket for intravitreal anti-VEGF therapy for CI-DME, and only a few get the cost covered by insurance. Individuals with diabetes also have other complications such as diabetic kidney disease and cardiovascular disease, which add to the healthcare costs and burden.
There are a few reports on compliance in patients with DR.[8] The compliance in patients with DME is not studied as extensively. One study reported that approximately one in four patients with non-proliferative DR who had DME had no follow-up visit for at least 1 year after anti-VEGF injection.[9] A study on the impact of compliance among patients with DME treated with anti-VEGF injections over 2 years showed that patients with poor compliance rates revealed significantly worse visual outcomes compared to patients with good therapy adherence and 13 times higher risk of developing proliferative DR.[10]
A study conducted by Kelkar et al.[11] showed that in patients in India who underwent intravitreal injections for various indications such as DME, age-related macular degeneration (AMD), or retinal vein occlusion (RVO), over half of them were lost to follow-up. The study mentioned that the main reasons for follow-up loss were non-affordability and no improvement in vision. However, in our study, the visual acuity status and stages of DME did not show any statistical difference in both centers.
A study by Kim et al.[2] on the visual outcome of DME on patients who were lost to follow-up for more than 1 year showed that poor response after initial injections is associated with a higher risk of non-compliance. In our study, at 1-month follow-up, the diabetes care center had better DME outcomes than the eye care center, which may contribute to reduced compliance in the eye care center patients. The other reason may be that patients who are more ill report their symptoms more frequently because diabetes care centers focus on treating coexisting illnesses such as cardiovascular disease, retinopathy, nephropathy, and diabetic foot care.
Two published studies focused on comparing DME and age-related macular degeneration (AMD) patients and did not assess in detail the reasons for non-compliance. According to the telephone survey conducted as part of the study, the rates of DME and AMD patients being 100 days or later for their appointment were 46% and 22%, respectively, with comorbidities being the main reason.[12] Patients with DME in the United States had a 1.591 times higher chance of canceling or no-showing their appointments than patients with wet AMD, according to an anonymous survey issued to retina doctors.[13]
No statistically significant difference was seen in the compliance among the proportion of DM based on gender in our study. In contrast, a male preponderance was seen in more extensive studies.[14-16] The presence of other systemic diseases showed higher odds for non-compliance in the eye center, and it was statistically significant. Numerous comorbidities associated with diabetes and advancing age often lead to increased dependency and the burden of repeated consultations in multiple specialties. This may divert attention away from eye care clinics, especially if the patient does not have a perceivable visual decline. However, to avoid organ and life loss, people with diabetes must comply with all areas of their healthcare.[17]
Despite advancements in treatment, non-compliance remains a significant barrier to effective care in DR, especially in DME. Providing comprehensive diabetes care, rather than eye care alone, seems to have improved the compliance of visits for eye care at the diabetes center in our study.
This study has assessed various parameters and compared compliance to follow-up after intravitreal pharmacotherapy for DME at an eye care facility versus a diabetes care facility. The analysis did not include patients who did not come for the follow-up. The retrospective design and tracking of the reasons for non-compliance in patients who failed to come for follow-ups in both groups and other parameters such as glycated haemoglobin (HbA1c), body mass index (BMI), and smoking status were not available for all patients; these were the major limitations of the study.
Conclusion
The key component for successful DME management is adherence to a rigorous treatment and follow-up examination regime. Our study shows that by providing a holistic approach to comprehensive diabetes care under one roof, compliance with follow-up can be improved in people with DME. To conclude that a holistic approach at a diabetic care center resolves non-adherence brought on by lost follow-up may only be one of several challenges to properly treating CI-DME. However, this study sample from specialized care centers may not represent all care levels. Further studies from diverse healthcare settings and general practitioners in the community may give us a more composite picture.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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