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Trial registered on ANZCTR


Registration number
ACTRN12622000492752
Ethics application status
Approved
Date submitted
16/03/2022
Date registered
28/03/2022
Date last updated
1/03/2023
Date data sharing statement initially provided
28/03/2022
Type of registration
Prospectively registered

Titles & IDs
Public title
Cost Effectiveness and Efficacy of Standalone Stents as Second-Stage Surgery Study: SUCCESSES
Scientific title
Cost Effectiveness and Efficacy of Standalone Stents as Second-Stage Surgery in Glaucoma Patients Undergoing Cataract Surgery: SUCCESSES
Secondary ID [1] 306655 0
Nil known
Universal Trial Number (UTN)
Trial acronym
SUCCESSES
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Glaucoma 325589 0
Cataract 325590 0
Primary open angle glaucoma 325591 0
Ocular hypertension 325592 0
Cataract Surgery 325723 0
Condition category
Condition code
Eye 322954 322954 0 0
Diseases / disorders of the eye
Surgery 323067 323067 0 0
Other surgery

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
An iStent (Glaukos Corporation, Laguna Hills, CA, USA) is a minimally invasive glaucoma surgery device, used widely for glaucoma and ocular hypertension. It is an ab-interno (i.e. inserted from inside the eye) trabecular bypass stent (i.e. crosses the trabecular meshwork, the point of maximum resistance in most glaucoma). The iStent is made of non-ferromagnetic, heparin-coated, surgical grade titanium.

This study is based on the concept of staging iStents. In patients with both cataracts and glaucoma, who would meet criteria for iStent with cataract surgery, we would perform only cataract surgery (which is standard of care) and delay the insertion of an iStent (which is still an emerging technology, not offered in all public hospital departments). Then, three months after surgery, if the same indications for iStent are still met, a second-stage standalone iStent insertion would be performed.

The surgeries will be performed by ophthalmologists, specifically- glaucoma specialists Prof Tony Wells, Dr Jesse Gale and Dr Nicole Lim. The approximate surgical time is 20 minutes for cataract surgery (first stage) and 10 minutes for iStent surgery.

The indications for iStent placement that must be met for insertion include:
Either a) IOP over target; OR b) at least one recognisable side effect of drops

Target IOP will be standardised (as is usual in our clinical practice) based on the Mean deviation (MD) of visual field:
1) if there is no glaucoma (ocular hypertension requiring treatment), target IOP equal to 21 mmHg,
2) if glaucoma is mild (MD greater than -6 dB), target IOP equal to 18 mmHg
3) if glaucoma is moderate (MD between -6 dB and -12 dB), target IOP equal to 15 mmHg
4) if glaucoma is advanced (MD less than -12 dB), target IOP equal to 12 mmHg
all of these categories and targets are modified by the clinician as appropriate, such as when progression is known to occur despite achieving target IOP .

Adherence to the intervention will be monitored by the lead investigator, who will audit participant records and operation reports at regular intervals (every 3 months) throughout the study period.
Intervention code [1] 323113 0
Treatment: Devices
Intervention code [2] 323180 0
Treatment: Surgery
Comparator / control treatment
No control group -the main study outcome is the proportion of patients who proceed to second stage iStent implantation.
Control group
Uncontrolled

Outcomes
Primary outcome [1] 330737 0
The main outcome is the proportion of patients who proceed to second stage iStent implantation. This will be assessed by auditing the study database. The study data base will be updated at each clinic visit and after any surgical intervention.
Timepoint [1] 330737 0
Assessed at 6 months, 12 months (primary endpoint), 3 years post-index surgery.
Secondary outcome [1] 407386 0
Intraocular pressure (IOP) - measured using Goldmann applanation tonometry
All IOP measurements in the study will be collected in a repeated (twice, a third time if >2 mmHg difference) and masked manner.
Timepoint [1] 407386 0
6 months, 12 months, 3 years post-index surgery.
Secondary outcome [2] 407387 0
Glaucoma-related quality of life measured with the glaucoma utility index (GUI) questionnaire (Burr et al, Optometry and Vision Science 2007)
Timepoint [2] 407387 0
6 months, 12 months, 3 years post-index surgery
Secondary outcome [3] 407388 0
Cost-utility analysis assessed by calculating the difference between resource use and costs (operating theatre time, consumable equipment, iStents) from hospital medical records, local theatre procurement data and patient out-of-pocket costs.
Timepoint [3] 407388 0
6 months, 12 months, 3 years post-index surgery
Secondary outcome [4] 407777 0
Visual acuity measured by Logmar visual acuity score
Timepoint [4] 407777 0
6 months, 12 months, 3 years
Secondary outcome [5] 407778 0
Number of glaucoma drops measured by accessing study data base (updated at each clinic visit)
Timepoint [5] 407778 0
6 months, 12 months, 3 years
Secondary outcome [6] 407779 0
Need for more glaucoma surgery measured by access to study database (updated at each clinic visit and after any participant undergoes an operation), monitored by lead investigator audit of all study participant records every 3 months
Timepoint [6] 407779 0
6 months, 12 months, 3 years

Eligibility
Key inclusion criteria
1. Visually significant cataract requiring surgery with visual acuity (VA) 6/9 or worse. Important issues about equity of access to cataract surgery are addressed below.
2. Diagnosis of Ocular Hypertension (OHT) or mild to moderate open angle glaucoma (including primary open angle, pigment dispersion, pseudoexfoliation), taking at least one topical glaucoma medication (eye drops)
3. Target IOP greater than or equal to 15 mmHg
4. Either a) IOP over target; OR b) at least one recognisable side effect of drops
5. Willing and able to give informed consent
6. Age greater than 18yrs
Minimum age
19 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Low tension, angle closure, neovascular, uveitic, traumatic or other secondary glaucoma
2. Prior incisional glaucoma surgery or cyclodestructive procedure
3. Selective laser trabeculoplasty (SLT) performed within 60 days of recruitment
4. Inability to safely perform iStent implantation, such as corneal opacity impeding gonioscopy view of nasal angle
5. Inability to attend follow up

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The first analysis is the survival curve representing the proportion of patients who remain free of side effects and at their target IOP after cataract surgery alone. Those who do not meet both criteria will have second-stage stent implantation. This proportion receiving stents will grow over time, and the comparison group is the concept that 100% of the participants would be considered eligible for stent implantation before their cataract. We are analysing whether the costs of the stent at the time of cataract surgery are outweighed by the costs of theatre for second stage implantation in some patients.

The null hypothesis is that the total cost of stents implanted as a primary procedure with cataract surgery in these participants would be the same as the cost of delaying the stent implantation for only those who still meet indications at 3 months (no difference). The alternative hypothesis is that the cost of second-stage implantation is different to the cost of implanting stents as a primary procedure with cataract surgery (greater or less, a two-tailed analysis). This outcome is modelled from the cost per cataract operation, the cost of cataract surgery with stent implantation, and the cost of standalone stent implantation.

The primary outcome of the study is thus the proportion of patients who require second-stage stent implantation, which drives the cost calculation.

The utility, or benefit, side of the equation is measured with the glaucoma utility index (GUI, a short questionnaire) and other secondary outcomes such as visual acuity, number of glaucoma drops, side effects (GUI questions 5 and 6) and the need for more glaucoma surgery.

A secondary analysis will be pre-operative factors that predict the need for, or benefit from, iStent implantation.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
1/04/2022
Actual
13/04/2022
Date of last participant enrolment
Anticipated
1/04/2025
Actual
Date of last data collection
Anticipated
1/06/2028
Actual
Sample size
Target
97
Accrual to date
10
Final
Recruitment outside Australia
Country [1] 24659 0
New Zealand
State/province [1] 24659 0
Wellington

Funding & Sponsors
Funding source category [1] 310981 0
Hospital
Name [1] 310981 0
Wellington Hospital, Capital and Coast District Health Board
Country [1] 310981 0
New Zealand
Primary sponsor type
Individual
Name
Dr Jesse Gale
Address
Wellington Hospital
Riddiford Street,
Newtown
Wellington 6021
Country
New Zealand
Secondary sponsor category [1] 312291 0
Individual
Name [1] 312291 0
Dr Nicole Lim
Address [1] 312291 0
Wellington Hospital
Riddiford Street,
Newtown
Wellington 6021
Country [1] 312291 0
New Zealand
Secondary sponsor category [2] 312398 0
Individual
Name [2] 312398 0
Prof Tony Wells
Address [2] 312398 0
Wellington Hospital
Riddiford Street
Wellington 6023
Country [2] 312398 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 310536 0
Northern B Health and Disability Ethics Committee, New Zealand
Ethics committee address [1] 310536 0
Ministry of Health
133 Molesworth Street
PO Box 5013
Wellington 6011
Ethics committee country [1] 310536 0
New Zealand
Date submitted for ethics approval [1] 310536 0
Approval date [1] 310536 0
28/01/2022
Ethics approval number [1] 310536 0

Summary
Brief summary
This study is based on the concept of staging cataract and iStent surgery (a minimally invasive glaucoma device). In patients with both cataracts and glaucoma, we would perform the cataract surgery first (which is standard of care) and delay the insertion of an iStent. The iStent would only be inserted (as a second stage procedure) if it is still required at any point from 3 months after the cataract surgery i.e. the intraocular pressure remains uncontrolled or there are side effects from the eye drops. The hypothesis is that if iStent insertion is not usually required after cataract surgery, then two-stage insertion would save money and unnecessary implantation of stents, but if iStent insertion is required after most cataract operations in glaucoma patients, then two-stage insertion would cost more money in additional theatre visits.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 117998 0
Dr Jesse Gale
Address 117998 0
Eye Clinic
Level 9
Wellington Hospital
Riddiford Street, Newtown
Wellington 6021
Country 117998 0
New Zealand
Phone 117998 0
+64211272979
Fax 117998 0
Email 117998 0
[email protected]
Contact person for public queries
Name 117999 0
Jesse Gale
Address 117999 0
Eye Clinic
Level 9
Wellington Hospital
Riddiford Street, Newtown
Wellington 6021
Country 117999 0
New Zealand
Phone 117999 0
+64211272979
Fax 117999 0
Email 117999 0
[email protected]
Contact person for scientific queries
Name 118000 0
Jesse Gale
Address 118000 0
Eye Clinic
Level 9
Wellington Hospital
Riddiford Street, Newtown
Wellington 6021
Country 118000 0
New Zealand
Phone 118000 0
+64211272979
Fax 118000 0
Email 118000 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
After de-identification, individual participant data underlying published results only - including proportion of patients who proceed to second stage iStent implantation, patient demographics, IOP control, glaucoma-related quality of life questionnaire score.
When will data be available (start and end dates)?
Beginning 3 months and ending 5 years following main results publication;
Available to whom?
Anonymous data will be available to anyone who wishes to access it
Available for what types of analyses?
Any type
How or where can data be obtained?
Contact via the Principal Investigator (Dr Jesse Gale, [email protected])


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
15388Study protocol    383735-(Uploaded-13-03-2022-08-38-55)-Study-related document.docx
15389Informed consent form    383735-(Uploaded-28-03-2022-05-46-25)-Study-related document.docx
15390Clinical study report  [email protected] Not yet available
15391Ethical approval    383735-(Uploaded-13-03-2022-08-39-37)-Study-related document.pdf



Results publications and other study-related documents

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