Association Between Change in Visual Acuity and Change in Central Subfield Thickness During Treatment of Diabetic Macular Edema in Participants Randomized to Aflibercept, Bevacizumab, or Ranibizumab: A Post Hoc Analysis of the Protocol T Randomized Clinical Trial.

IMPORTANCE: The determination of optical coherence tomography (OCT) central subfield thickness (CST) is an objective measure, and visual acuity (VA) is a subjective measure. Therefore, using OCT CST changes as a surrogate for VA changes in diabetic macular edema seems reasonable. However, studies suggest that change in OCT CST following anti-vascular endothelial growth factor (anti-VEGF) treatment for diabetic macular edema is correlated with changes in VA but varies substantially among individuals, and so may not be a good surrogate for changes in VA. OBJECTIVE: To determine associations between changes in VA and changes in OCT CST across 3 anti-VEGF agents (aflibercept, bevacizumab, or ranibizumab) used in a randomized clinical trial for diabetic macular edema. DESIGN, SETTING, AND PARTICIPANTS: Post hoc analyses were conducted of DRCR Retina Network Protocol T among 652 of 660 participants (98.8%) meeting inclusion criteria for this investigation. The study was conducted between August 22, 2012, and September 23, 2015. The post hoc data collection and analysis were performed from May 29 to July 11, 2018. INTERVENTIONS: Six monthly intravitreous anti-VEGF injections (unless success was achieved after 3-5 months) were administered; subsequent injections or focal/grid laser photocoagulation treatments were given as needed per protocol to achieve stability. MAIN OUTCOMES AND MEASURES: Association between changes in VA letter score with changes in CST at 12, 52, and 104 weeks after randomization to aflibercept, bevacizumab, or ranibizumab. RESULTS: Of the 652 participants, 304 were women (46.6%); median age was 61 years (interquartile range, 54-67 years). The correlation between CST and VA at the follow-up visits was 0.24 (95% CI, 0.16-0.31) in 616 patients at 12 weeks, 0.31 (95% CI, 0.24-0.38) in 609 patients at 52 weeks, and 0.23 (95% CI, 0.15-0.31) in 566 patients at 104 weeks. The correlation coefficients of change in VA vs change in OCT CST for these time intervals were 0.36 (95% CI, 0.29-0.43) at 12 weeks, 0.36 (95% CI, 0.29-0.43) at 52 weeks, and 0.33 (95% CI, 0.26-0.41) at 104 weeks. CONCLUSIONS AND RELEVANCE: Changes in CST appear to account for only a small proportion of the total variation in changes in VA. These findings do not support using changes in OCT CST as a surrogate for changes in VA in phase 3 clinical trials evaluating anti-VEGF for diabetic macular edema or as a guide to inform the physician or patient about changes in VA after anti-VEGF treatment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01627249.

Factors Associated With Visual Acuity and Central Subfield Thickness Changes When Treating Diabetic Macular Edema With Anti-Vascular Endothelial Growth Factor Therapy: An Exploratory Analysis of the Protocol T Randomized Clinical Trial.

Importance: Identifying the factors that are associated with the magnitude of treatment benefits from anti-vascular endothelial growth factor (anti-VEGF) therapy for diabetic macular edema (DME) may help refine treatment expectations. Objective: To identify the baseline factors that are associated with vision and anatomic outcomes when managing DME with anti-VEGF and determine if there are interactions between factors and the agent administered. Design, Setting, and Participants: This post hoc analysis of data from the Diabetic Retinopathy Clinical Research Network multicenter randomized clinical trial , Protocol T, was conducted between December 2016 and December 2017. Between August 22, 2012, and August 28, 2013, 660 participants were enrolled with central-involved DME and vision impairment (approximate Snellen equivalent, 20/32-20/320). Interventions: Repeated 0.05-mL intravitreous injections of 2.0-mg aflibercept (201 eyes), 1.25-mg bevacizumab (185 eyes), or 0.3-mg ranibizumab (192 eyes) per protocol. Main Outcomes and Measures: Change in visual acuity (VA) and optical coherence tomography (OCT) central subfield thickness at 2 years and change in VA over 2 years (area under the curve [AUC]). Results: Among 578 participants, the median age (interquartile range) was 61 (54-67) years. Across anti-VEGF treatment groups, each baseline factor was associated with mean improvement in VA and a reduction in central DME compared with the baseline. For every decade of participant age, the mean VA improvement was reduced by 2.1 letters (95% CI, -3.0 to -1.2; P < .001) in the VA and 1.9 letters (95% CI, -2.4 to -1.3; P < .001) in the VA AUC analyses. For each 1% increase in hemoglobin A1c levels, VA improvement was reduced by 1 letter in the VA (95% CI, -1.5 to -0.5; P < .001) and 0.5 letters (95% CI, -0.9 to -0.2; P < .001) in the VA AUC analyses. Eyes with no prior panretinal photocoagulation (PRP) and less than severe nonproliferative diabetic retinopathy had an approximately 3-letter improvement in the VA (95% CI, 0.9-5.4; P = .007) and VA AUC (95% CI, 1.3-4.2; P < .001) analyses compared with eyes with prior PRP. On average, African American participants had greater reductions in central subfield thickness compared with eyes of white participants (-27.3 µm, P = .01), as did eyes with central subretinal fluid compared with eyes without this OCT feature (-22.9 µm, P = .01). There were no interactions between the predictive factors and the specific anti-VEGF agent that was administered for any VA or OCT outcome. Conclusions and Relevance: Lower hemoglobin A1c levels were associated with the magnitude of vision improvement following anti-VEGF therapy, providing further evidence to encourage glycemic control among persons with diabetes. Younger patients and those without prior PRP might expect greater improvement in VA than older patients or those with prior PRP.

PANRETINAL PHOTOCOAGULATION VERSUS RANIBIZUMAB FOR PROLIFERATIVE DIABETIC RETINOPATHY: Comparison of Peripapillary Retinal Nerve Fiber Layer Thickness in a Randomized Clinical Trial.

PURPOSE: Compare changes in retinal nerve fiber layer (RNFL) thickness between eyes assigned to intravitreous ranibizumab or panretinal photocoagulation and assess correlations between changes in RNFL and visual field sensitivity and central subfield thickness. METHODS: Eyes with proliferative diabetic retinopathy were randomly assigned to ranibizumab or panretinal photocoagulation. Baseline and annual follow-up spectral domain optical coherence tomography RNFL imaging, optical coherence tomography macular imaging, and automated static perimetry (Humphrey visual field 60-4 algorithm) were performed. RESULTS: One hundred forty-six eyes from 120 participants were analyzed. At 2 years, for the ranibizumab (N = 74) and panretinal photocoagulation (N = 66) groups, respectively, mean change in average RNFL thickness was -10.9 ± 11.7 µm and -4.3 ± 11.6 µm (difference, -4.9 µm; 95% confidence interval [-7.2 µm to -2.6 µm]; P < 0.001); the correlation between change in RNFL thickness and 60-4 Humphrey visual field mean deviation was -0.27 (P = 0.07) and +0.33 (P = 0.035); the correlation between change in RNFL thickness and central subfield thickness was +0.63 (P < 0.001) and +0.34 (P = 0.005), respectively. CONCLUSION: At 2 years, eyes treated with ranibizumab had greater RNFL thinning than eyes treated with panretinal photocoagulation. Correlations between changes in RNFL thickness, visual field, and central subfield thickness suggest that the decrease in RNFL thickness with ranibizumab is likely due to decreased edema rather than loss of axons.

Comparison of Early Treatment Diabetic Retinopathy Study Standard 7-Field Imaging With Ultrawide-Field Imaging for Determining Severity of Diabetic Retinopathy.

Importance: Moderate to substantial agreement between Early Treatment Diabetic Retinopathy Study (ETDRS) 7-field imaging and ultrawide-field (UWF) imaging has been suggested in single-center studies. Comparing images obtained by multiple centers could increase confidence that UWF images can be used reliably in place of ETDRS imaging in future clinical trials. Objective: To compare diabetic retinopathy (DR) severity from modified ETDRS 7-field imaging and UWF imaging. Design, Setting, and Participants: This preplanned, cross-sectional analysis included modified ETDRS 7-field images obtained using the Diabetic Retinopathy Clinical Research Network acquisition protocol and UWF images obtained captured with the Optos 200Tx system (Optos, PLC) from adult participants (≥18 years old) with type 1 or type 2 diabetes. Both image types were evaluated by trained graders masked to clinical data. Data collection occurred from February 2015 to December 2015, and data analysis from June 2016 to December 2017. Main Outcomes and Measures: Agreement between UWF images, UWF images masked to include only the ETDRS 7-field area, and ETDRS 7-field images were calculated using κ statistics. Results: A total of 764 eyes from 385 participants were included; participants had a median (IQR) age of 62.2 (53.6-69.2) years, 194 (50.4%) were women, and 256 (66.5%) were white. Of 742 eyes with both ETDRS 7-field images and UWF masked images graded, 359 (48.4% [95% CI, 44.4%-52.4%]) eyes had exact agreement, and 653 eyes (88.0% [95% CI, 85.2%-90.3%]) agreed within 1 step (weighted κ, 0.51 [95% CI, 0.44-0.58]). After open adjudication by an independent senior grader of all images with more than a 2-step discrepancy, perfect agreement was found in 435 eyes (59.0% [95% CI, 55.1%-62.8%]) and agreement within 1 step in 714 eyes (96.9% [95% CI, 95.1%-98.0%]; κ, 0.77 [95% CI, 0.73-0.82]). Ability of the imaging modalities to detect retinopathy severity in an individual eye was considered similar in 59 eyes (50.9% [95% CI, 41.3%-60.4%]), better for ETDRS 7-field imaging in 22 eyes (19.0% [95% CI, 12.5%-27.7%]), and better for UWF-masked images in 31 eyes (26.7% [95% CI 18.8%-36.5%]). Comparing UWF masked and unmasked images, 94 of 751 eyes (12.5%) had DR graded as at least 1 step more severe on UWF unmasked images vs UWF masked images. Predominantly peripheral DR lesions were present in 308 of 751 eyes (41.0%); this suggested increased DR severity by 2 or more steps in 34 eyes (11.0%). Conclusions and Relevance: Imaging by the ETDRS 7-field and UWF imaging systems have moderate to substantial agreement when determining the severity of DR within the 7 standard fields. Disparities in an individual eye are equivalently distributed between imaging modalities and can be better or worse on 1 or the other. Longitudinal follow-up will evaluate the primary outcome of this study to determine if peripheral retinal findings are associated with future retinopathy outcomes.

CHANGES IN DIABETIC RETINOPATHY SEVERITY WHEN TREATING DIABETIC MACULAR EDEMA WITH RANIBIZUMAB: DRCR.net Protocol I 5-Year Report.

PURPOSE: To explore 5-year changes from baseline in diabetic retinopathy severity among eyes treated with ranibizumab for diabetic macular edema. METHODS: Diabetic retinopathy severity was assessed from study visits and annual fundus photographs among participants in Protocol I (DRCR.net). The proportion of eyes that improved at annual examinations and the cumulative probability of worsening through 5 years were estimated. RESULTS: Among 235 participants with nonproliferative diabetic retinopathy at baseline, there were 29%, 28%, and 32% of eyes with retinopathy improvement at 1, 3, and 5 years, respectively. Among 111 participants with proliferative diabetic retinopathy, corresponding improvement percentages were 38%, 35%, and 23%. The 5-year cumulative probability of worsening was 18% (95% CI: 14%-25%) among nonproliferative diabetic retinopathy eyes and 31% (95% CI: 23%-42%) among proliferative diabetic retinopathy eyes (P = 0.01). In Years 1, 3, and 5, the mean (SD) number of ranibizumab injections was 8.1 (2.5), 2.2 (2.6), and 1.8 (2.6) for nonproliferative diabetic retinopathy eyes, and 9.0 (2.8), 2.3 (2.9), and 1.7 (2.6) for proliferative diabetic retinopathy eyes, respectively. Proportions with improvement or rates of worsening did not change with time. CONCLUSION: Individuals receiving ranibizumab therapy for diabetic macular edema may have favorable changes in DR severity throughout a 5-year period concomitant with sequential reduction in anti-vascular endothelial growth factor therapy.

Characterizing permuted block randomization as a big stick procedure.

There are numerous approaches to randomizing patients to treatment groups in clinical trials. The most popular is permuted block randomization, and a newer and better class, which is gaining in popularity, is the so-called class of MTI procedures, which use a big stick to force the allocation sequence back towards balance when it reaches the MTI (maximally tolerated imbalance). Three prominent members of this class are the aptly named big stick procedure, Chen's procedure, and the maximal procedure. As we shall establish in this article, blocked randomization, though not typically cast as an MTI procedure, does in fact use the big stick as well. We shall argue that its weaknesses, which are well known, arise precisely from its improper use, bordering on outright abuse, of this big stick. Just as rocket powered golf clubs add power to a golf swing, so too does the big stick used by blocked randomization hit with too much power. In addition, the big stick is invoked when it need not be, thereby resulting in the excessive prediction for which permuted blocks are legendary. We bridge the gap between the MTI procedures and block randomization by identifying a new randomization procedure intermediate between the two, namely based on an excessively powerful big stick, but one that is used only when needed. We shall then argue that the MTI procedures are all superior to this intermediate procedure by virtue of using a restrained big stick, and that this intermediate procedure is superior to block randomization by virtue of restraint in when the big stick is invoked. The transitivity property then completes our argument.