Diabetic macular oedema and diode subthreshold micropulse laser (DIAMONDS): study protocol for a randomised controlled trial
- PMID: 30755274
- PMCID: PMC6373040
- DOI: 10.1186/s13063-019-3199-5
Diabetic macular oedema and diode subthreshold micropulse laser (DIAMONDS): study protocol for a randomised controlled trial
Abstract
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).
Keywords: Anti-VEGFs; Cost-effectiveness; DME; DMO; Diabetes; Edema; Laser; Micropulse; Oedema; RCT.
Conflict of interest statement
Ethics approval and consent to participate
Ethical approval for this study was granted centrally by the Office for Research Ethics Committees Northern Ireland, REC Reference 16/NI/0145; approval was also obtained locally for all participating sites.
Eligible patients may only be included in the trial after written informed consent is obtained. Informed consent must be obtained prior to conducting any trial-specific procedures and the process for obtaining informed consent must be documented in the patient’s medical records (source documents will be reviewed at the time of on-site monitoring visits). DIAMONDS investigators will conduct the study in compliance with the protocol given approval or favourable opinion by the Research Ethics Committee (REC). Changes to the protocol may require ethics committee approval prior to implementation (currently, protocol version 4 is in use). The NICTU in collaboration with the Sponsor will submit all protocol modifications to the REC for review in accordance with the governing regulations.
The safety of the treatment will be assessed at each visit by noting any complications during or after laser treatment (including any self-reported visual disturbances) and visual acuity loss. Participants will be asked about reduced colour vision, presence of paracentral scotomas and/or distortion at each scheduled visit and whether they have had any planned or unforeseen hospital visits/admissions or treatments related to eye problems. Although serious adverse events (SAE) related to the study procedures are unlikely, a record will be kept of these and they will be reported to the ethics committee (Office for Research Ethics Committees Northern Ireland (ORECNI)).
In order to maintain participant’s confidentiality, a unique study identification number will be used for each participant. Study reports and communication about the study will identify the patients by their assigned unique trial identifier only. Computers where information will be stored will be password protected. Patient confidentiality will be maintained at every stage and will not be made publicly available to the extent permitted by the applicable laws and regulations.
The DMEC will be responsible for safeguarding the interests of trial participants. The DMEC will monitor safety and efficacy and advise the TSC to protect the validity and credibility of the trial.
A report containing the methodology and results of DIAMONDS will be published as an HTA monograph, freely accessible via the NIHR HTA web site. The Royal College of Ophthalmologists will be contacted when the study is completed to allow the trials findings to be incorporated in future diabetic retinopathy guidelines. We also plan to publish the findings in articles in national and international peer-reviewed journals and to present the findings at both national and international meetings and to patient groups.
Consent for publication
Not applicable (the manuscript does not contain data from any individual person).
Competing interests
NL: none; EG: None; NW: none; AAB: none; HM: none; DM: none; NA: none; TA: none; CB has been an ad-hoc advisor for Alcon, Bayer, Novartis, Alimera sciences and Allergan; VC is a part-time employee of Boehringer Ingelheim International GmBH (BII), Germany - this study, however, is not being undertaken as part of the employment with BII and, thus, the content of this manuscript is not endorsed by BII; VC has also received speaker fees from Quantel Medical, France; LD has performed advisory board work for Bayer, Novartis, Allergan, Alimera Thrombogenics and Alcon and has had travel grants from Bayer, Novartis and Allergan, and research studies sponsored by Bayer, Novartis, Allergan, Roche and Alimera; HE has been ad-hoc advisor for Novartis, Bayer, received educational travel grants from Novartis, Bayer and Allergan and has given a remunerated talk for Iridex; SF: none; SG: none; FG has had advisory roles for Novartis, Bayer, Alimera and Roche, received research funding from Bayer and received travel grants from Bayer and Allergan; MG: none; RH: none; GM: none; AS: none; SS has received research grants, travel feeds and attended advisory board meetings of Novartis, Bayer, Roche, Allergan, Heidelberg Engineering, Optos Plc and Boehringer Ingleheim; MS: none; DS acted as consultant to Alcon, attended advisory boards for Novartis and Bayer and received research funding from Bayer and Alcon; JT has received travel grants from Bayer and research support from Novartis; CA: none; CC: none; MM: none; MC: none. None of the authors have any commercial interest in any of the diagnostic or treatment devices used in this trial, including the lasers.
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References
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- National Institute for Healthcare Excellence. www.nice.org.uk/guidance/ta274. Accessed 28 Sept 2018.
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- National Institute for Healthcare Excellence. www.nice.org.uk/guidance/ta346. Accessed 28 Sept 2018.
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