Diabetic Macular Edema and Diode Subthreshold Micropulse Laser: A Randomized Double-Masked Noninferiority Clinical Trial

PURPOSE

To determine clinical effectiveness, safety, and cost-effectiveness of subthreshold micropulse laser (SML), compared with standard laser (SL), for diabetic macular edema (DME) with central retinal thickness (CRT) < 400 μm.

DESIGN

Pragmatic, multicenter, allocation-concealed, double-masked, randomized, noninferiority trial.

PARTICIPANTS

Adults with center-involved DME < 400 μm and best-corrected visual acuity (BCVA) of > 24 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in one/both eyes.

METHODS

Randomization 1:1 to 577 nm SML or SL treatment. Retreatments were allowed. Rescue with intravitreal anti-vascular endothelial growth factor therapies or steroids was permitted if 10 or more ETDRS letter loss occurred, CRT increased > 400 μm, or both.

MAIN OUTCOME MEASURES

Primary outcome was mean change in BCVA in the study eye at 24 months (noninferiority margin 5 ETDRS letters). Secondary outcomes were mean change from baseline to month 24 in binocular BCVA; CRT and mean deviation of Humphrey 10-2 visual field in the study eye; percentage meeting driving standards; EuroQoL EQ-5D-5L, 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), and Vision and Quality of Life Index (VisQoL) scores; cost per quality-adjusted life-years (QALYs) gained; adverse effects; and number of laser and rescue treatments.

RESULTS

The study recruited fully (n = 266); 87% of SML-treated and 86% of SL-treated patients had primary outcome data. Mean ± standard deviation BCVA change from baseline to month 24 was -2.43 ± 8.20 letters and -0.45 ± 6.72 letters in the SML and SL groups, respectively. Subthreshold micropulse laser therapy was deemed not only noninferior but also equivalent to SL therapy because the 95% confidence interval (CI; -3.9 to -0.04 letters) lay wholly within both upper and lower margins of the permitted maximum difference (5 ETDRS letters). No statistically significant difference was found in binocular BCVA (0.32 ETDRS letters; 95% CI, -0.99 to 1.64 ETDRS letters; P = 0.63); CRT (-0.64 μm; 95% CI, -14.25 to 12.98 μm; P = 0.93); mean deviation of the visual field (0.39 decibels (dB); 95% CI, -0.23 to 1.02 dB; P = 0.21); meeting driving standards (percentage point difference, 1.6%; 95% CI, -25.3% to 28.5%; P = 0.91); adverse effects (risk ratio, 0.28; 95% CI, 0.06-1.34; P = 0.11); rescue treatments (percentage point difference, -2.8%; 95% CI, -13.1% to 7.5%; P = 0.59); or EQ-5D, NEI-VFQ-25, or VisQoL scores. Number of laser treatments was higher in the SML group (0.48; 95% CI, 0.18-0.79; P = 0.002). Base-case analysis indicated no differences in costs or QALYs.

CONCLUSIONS

Subthreshold micropulse laser therapy was equivalent to SL therapy, requiring slightly higher laser treatments.

Standard threshold laser versus subthreshold micropulse laser for adults with diabetic macular oedema: the DIAMONDS non-inferiority RCT

BACKGROUND

The National Institute for Health and Care Excellence recommends macular laser to treat diabetic macular oedema with a central retinal subfield thickness of < 400 µm on optical coherence tomography. The DIAMONDS (DIAbetic Macular Oedema aNd Diode Subthreshold micropulse laser) trial compared standard threshold macular laser with subthreshold micropulse laser to treat diabetic macular oedema suitable for macular laser.

OBJECTIVES

Determining the clinical effectiveness, safety and cost-effectiveness of subthreshold micropulse laser compared with standard threshold macular laser to treat diabetic macular oedema with a central retinal subfield thickness of < 400 µm.

DESIGN

A pragmatic, multicentre, allocation-concealed, double-masked, randomised, non-inferiority, clinical trial.

SETTING

Hospital eye services in the UK.

PARTICIPANTS

Adults with diabetes and centre-involving diabetic macular oedema with a central retinal subfield thickness of < 400 µm, and a visual acuity of > 24 Early Treatment Diabetic Retinopathy Study letters (Snellen equivalent > 20/320) in one/both eyes.

INTERVENTIONS

Participants were randomised 1 : 1 to receive 577 nm subthreshold micropulse laser or standard threshold macular laser (e.g. argon laser, frequency-doubled neodymium-doped yttrium aluminium garnet 532 nm laser); laser treatments could be repeated as needed. Rescue therapy with intravitreal anti-vascular endothelial growth factor therapies or steroids was allowed if a loss of ≥ 10 Early Treatment Diabetic Retinopathy Study letters between visits occurred and/or central retinal subfield thickness increased to > 400 µm.

MAIN OUTCOME MEASURES

The primary outcome was the mean change in best-corrected visual acuity in the study eye at 24 months (non-inferiority margin 5 Early Treatment Diabetic Retinopathy Study letters). Secondary outcomes included the mean change from baseline to 24 months in the following: binocular best-corrected visual acuity; central retinal subfield thickness; the mean deviation of the Humphrey 10-2 visual field in the study eye; the percentage of people meeting driving standards; and the EuroQol-5 Dimensions, five-level version, National Eye Institute Visual Function Questionnaire - 25 and Vision and Quality of Life Index scores. Other secondary outcomes were the cost per quality-adjusted life-years gained, adverse effects, number of laser treatments and additional rescue treatments.

RESULTS

The DIAMONDS trial recruited fully (n = 266); 87% of participants in the subthreshold micropulse laser group and 86% of participants in the standard threshold macular laser group had primary outcome data. Groups were balanced regarding baseline characteristics. Mean best-corrected visual acuity change in the study eye from baseline to month 24 was -2.43 letters (standard deviation 8.20 letters) in the subthreshold micropulse laser group and -0.45 letters (standard deviation 6.72 letters) in the standard threshold macular laser group. Subthreshold micropulse laser was deemed to be not only non-inferior but also equivalent to standard threshold macular laser as the 95% confidence interval (-3.9 to -0.04 letters) lay wholly within both the upper and lower margins of the permitted maximum difference (5 Early Treatment Diabetic Retinopathy Study letters). There was no statistically significant difference between groups in any of the secondary outcomes investigated with the exception of the number of laser treatments performed, which was slightly higher in the subthreshold micropulse laser group (mean difference 0.48, 95% confidence interval 0.18 to 0.79; p = 0.002). Base-case analysis indicated no significant difference in the cost per quality-adjusted life-years between groups.

FUTURE WORK

A trial in people with ≥ 400 µm diabetic macular oedema comparing anti-vascular endothelial growth factor therapy alone with anti-vascular endothelial growth factor therapy and macular laser applied at the time when central retinal subfield thickness has decreased to < 400 µm following anti-vascular endothelial growth factor injections would be of value because it could reduce the number of injections and, subsequently, costs and risks and inconvenience to patients.

LIMITATIONS

The majority of participants enrolled had poorly controlled diabetes.

CONCLUSIONS

Subthreshold micropulse laser was equivalent to standard threshold macular laser but required a slightly higher number of laser treatments.

TRIAL REGISTRATION

This trial is registered as EudraCT 2015-001940-12, ISRCTN17742985 and NCT03690050.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 50. See the NIHR Journals Library website for further project information.

Real-World Anti-Vascular Endothelial Growth Factor Therapy Outcomes in Myopic Choroidal Neovascularization

Aim

Evaluation of real-world outcomes of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy in the primary treatment of choroidal neovascularization (CNV) secondary to pathological myopia.

Patients and Methods

A retrospective cohort analysis of treatment naive patients with myopic CNV who received treatment with either intravitreal ranibizumab or aflibercept over a 12-year period from September 2007 to May 2020 was performed. Baseline features, treatment factors and outcomes were compared between younger and older patients and final visual outcome was assessed for associated factors.

Results

Thirty-seven eyes of 36 patients (24 females, 12 males) were included. Mean age was 58 years (range=26–89 years). Of these patients, 11/36 (31%) were ≤50 years of age and 25/36 (69%) were ≥51 years of age. Seventy-three percent (27/37) of eyes were phakic. One patient received bilateral treatment for myopic CNV. Median spherical equivalent was −8.50 diopters. Seventy percent (26/37) of eyes commenced primary treatment with ranibizumab, and 11/37 (30%) eyes commenced treatment with aflibercept. There were no significant differences between treatment factors and outcomes of younger and older patients. Median number of injections was 3 over a median follow-up period of 24.6 months. Mean CRT decreased by 126μm and median visual improvement was +6 letters. Analysis showed that younger age (p=0.022) and fewer injections (p=0.004) were associated with better visual outcomes.

Conclusion

Myopic CNV requires less frequent anti-VEGF intravitreal therapy over a shorter follow-up period than both neovascular age-related macular degeneration and diabetic macular edema. Increased frequency of administration of intravitreal anti-VEGF treatment did not improve vision. Younger age is associated with a better final visual outcome. These findings may help to advise patients about the prognosis of treatment and help guide treatment decisions.

United Kingdom Diabetic Retinopathy Electronic Medical Record (UK DR EMR) Users Group: report 4, real-world data on the impact of deprivation on the presentation of diabetic eye disease at hospital services

AIM

To assess the impact of deprivation on diabetic retinopathy presentation and related treatment interventions, as observed within the UK hospital eye service.

METHODS

This is a multicentre, national diabetic retinopathy database study with anonymised data extraction across 22 centres from an electronic medical record system. The following were the inclusion criteria: all patients with diabetes and a recorded, structured diabetic retinopathy grade. The minimum data set included, for baseline, age and Index of Multiple Deprivation, based on residential postcode; and for all time points, visual acuity, ETDRS grading of retinopathy and maculopathy, and interventions (laser, intravitreal therapies and surgery). The main  outcome measures were (1) visual acuity and binocular visual state, and (2) presence of sight-threatening complications and need for early treatment.

RESULTS

79 775 patients met the inclusion criteria. Deprivation was associated with later presentation in patients with diabetic eye disease: the OR of being sight-impaired at entry into the hospital eye service (defined as 6/18 to better than 3/60 in the better seeing eye) was 1.29 (95% CI 1.20 to 1.39) for the most deprived decile vs 0.77 (95% CI 0.70 to 0.86) for the least deprived decile; the OR for being severely sight-impaired (3/60 or worse in the better seeing eye) was 1.17 (95% CI 0.90 to 1.55) for the most deprived decile vs 0.88 (95% CI 0.61 to 1.27) for the least deprived decile (reference=fifth decile in all cases). There is also variation in sight-threatening complications at presentation and treatment undertaken: the least deprived deciles had lower chance of having a tractional retinal detachment (OR=0.48 and 0.58 for deciles 9 and 10, 95% CI 0.24 to 0.90 and 0.29 to 1.09, respectively); in terms of accessing treatment, the rate of having a vitrectomy was lowest in the most deprived cohort (OR=0.34, 95% CI 0.19 to 0.58).

CONCLUSIONS

This large real-world study suggests that first presentation at a hospital eye clinic with visual loss or sight-threatening diabetic eye disease is associated with deprivation. These initial hospital visits represent the first opportunities to receive treatment and to formally engage with support services. Such patients are more likely to be sight-impaired or severely sight-impaired at presentation, and may need additional resources to engage with the hospital eye services over complex treatment schedules.

Diabetic macular oedema and diode subthreshold micropulse laser (DIAMONDS): study protocol for a randomised controlled trial

BACKGROUND

In the UK, macular laser is the treatment of choice for people with diabetic macular oedema with central retinal subfield thickness (CST) < 400 μm, as per National Institute for Health and Care Excellence guidelines. It remains unclear whether subthreshold micropulse laser is superior and should replace standard threshold laser for the treatment of eligible patients.

METHODS

DIAMONDS is a pragmatic, multicentre, allocation-concealed, randomised, equivalence, double-masked clinical trial that aims to determine the clinical effectiveness and cost-effectiveness of subthreshold micropulse laser compared with standard threshold laser, for the treatment of diabetic macular oedema with CST < 400 μm. The primary outcome is the mean change in best-corrected visual acuity in the study eye from baseline to month 24 post treatment. Secondary outcomes (at 24 months) include change in binocular best corrected visual acuity; CST; mean deviation of the Humphrey 10-2 visual field; change in percentage of people meeting driving standards; European Quality of Life-5 Dimensions, National Eye Institute Visual Functioning Questionnaire-25 and VisQoL scores; incremental cost per quality-adjusted life year gained; side effects; number of laser treatments and use of additional therapies. The primary statistical analysis will be per protocol rather than intention-to-treat analysis because the latter increases type I error in non-inferiority or equivalence trials. The difference between lasers for change in best-corrected visual acuity (using 95% CI) will be compared to the permitted maximum difference of five Early Treatment Diabetic Retinopathy Study (ETDRS) letters. Linear and logistic regression models will be used to compare outcomes between treatment groups. A Markov-model-based cost-utility analysis will extend beyond the trial period to estimate longer-term cost-effectiveness.

DISCUSSION

This trial will determine the clinical effectiveness and cost-effectiveness of subthreshold micropulse laser, when compared with standard threshold laser, for the treatment of diabetic macular oedema, the main cause of sight loss in people with diabetes mellitus.

TRIAL REGISTRATION

International Standard Randomised Controlled Trials, ISRCTN17742985 . Registered on 19 May 2017 (retrospectively registered).