ANZCTR - Registration

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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]

Nil known

Universal Trial Number (UTN)

Trial acronym

SUCCESSES

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Glaucoma

Cataract

Primary open angle glaucoma

Ocular hypertension

Cataract Surgery

Condition category

Condition code

Eye

Diseases / disorders of the eye

Surgery

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]

Treatment: Devices

Intervention code [2]

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]

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]

Assessed at 6 months, 12 months (primary endpoint), 3 years post-index surgery.

Secondary outcome [1]

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]

6 months, 12 months, 3 years post-index surgery.

Secondary outcome [2]

Glaucoma-related quality of life measured with the glaucoma utility index (GUI) questionnaire (Burr et al, Optometry and Vision Science 2007)

Timepoint [2]

6 months, 12 months, 3 years post-index surgery

Secondary outcome [3]

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]

6 months, 12 months, 3 years post-index surgery

Secondary outcome [4]

Visual acuity measured by Logmar visual acuity score

Timepoint [4]

6 months, 12 months, 3 years

Secondary outcome [5]

Number of glaucoma drops measured by accessing study data base (updated at each clinic visit)

Timepoint [5]

6 months, 12 months, 3 years

Secondary outcome [6]

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]

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?

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

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Wellington

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

Wellington Hospital, Capital and Coast District Health Board

Address [1]

Riddiford Street,
Newtown
Wellington 6021

Country [1]

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]

Individual

Name [1]

Dr Nicole Lim

Address [1]

Wellington Hospital
Riddiford Street,
Newtown
Wellington 6021

Country [1]

New Zealand

Secondary sponsor category [2]

Individual

Name [2]

Prof Tony Wells

Address [2]

Wellington Hospital
Riddiford Street
Wellington 6023

Country [2]

New Zealand

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Northern B Health and Disability Ethics Committee, New Zealand

Ethics committee address [1]

Ministry of Health 
133 Molesworth Street
PO Box 5013
Wellington 6011

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

Approval date [1]

28/01/2022

Ethics approval number [1]

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

Dr Jesse Gale

Address

Eye Clinic
Level 9
Wellington Hospital
Riddiford Street, Newtown
Wellington 6021

Country

New Zealand

Phone

+64211272979

Fax

[email protected]

Contact person for public queries

Name

Jesse Gale

Address

Eye Clinic
Level 9
Wellington Hospital
Riddiford Street, Newtown
Wellington 6021

Country

New Zealand

Phone

+64211272979

Fax

[email protected]

Contact person for scientific queries

Name

Jesse Gale

Address

Eye Clinic
Level 9
Wellington Hospital
Riddiford Street, Newtown
Wellington 6021

Country

New Zealand

Phone

+64211272979

Fax

[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.	Type	Email	Other Details	Attachment
15388	Study protocol			383735-(Uploaded-13-03-2022-08-38-55)-Study-related document.docx
15389	Informed consent form			383735-(Uploaded-28-03-2022-05-46-25)-Study-related document.docx
15390	Clinical study report	[email protected]	Not yet available
15391	Ethical approval			383735-(Uploaded-13-03-2022-08-39-37)-Study-related document.pdf

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

Trial Review

Documents added manually

Documents added automatically