Evidence Table 8Carbonic anhydrase inhibitors vs. no treatment

Study detailsPatientsInterventionsOutcome measuresEffect sizeComments
Miglior et al., 200599

European Glaucoma Prevention Study (EGPS) Group.

Study design:
Double masked

Evidence level: 1+

Duration of follow-up:
Median 55.3 months.
Patient group: Consecutive patients from clinic population with ocular hypertension (30 years plus).

Setting: Patients from 18 centres in 4 European countries.

Inclusion: IOP (22–29mmHg), two normal and reliable visual fields and normal optic discs, PEX allowed (below 2%), normal optic discs in both eyes, open angle, PEX and PDS allowed.

Exclusion: Visual acuity below 20/40, previous intraocular surgery, previous laser trabeculoplasty within 3 months, secondary causes of elevated IOP.

All patients
N: 1077
Age (mean): 57.03 ± 10.3
Race: Caucasian: 1075, African European: 1 Asian: 1
Mean IOP: 23.6 ± 1.6

Group 1
N: 536
Age (mean): 56.42 ± 10.32
M/F: 232/304
Mean IOP: 23.4 ± 1.53
Dropouts: 191 (116 adverse events)

Group 2
N: 541
Age (mean): 57.63 ± 10.30
M/F: 259/282
Mean IOP: 23.5 ± 1.68
Drop outs: 134 (51 adverse events)
Group 1
Dorzolamide 2% (CAI) – three times daily.

Group 2
Placebo – three times daily.
Development of reproducible visual field defects:Group 1: 26/536 (4.9%)
Group 2: 38/541 (7.0%)
OR: 0.68 (95% CI: 0.41–1.12)
Funding: Supported by The European Commission (BIOMED II program, contract no.: BMH4-CT-96- 1598), and Merck (Whitehouse Station, NJ).

High dropouts (30.1%). A comparative analysis of the mean IOP between patients still in the study and those who voluntarily withdrew revealed a higher IOP level in the group of withdrawn patients.
It was not possible to calculate standard deviations for mean change in IOP from baseline at each follow up using Cochrane methods because no p values were reported..

Additional outcomes:

Randomisation by computer generated allocation sequence and allocation concealment. Patients and examiners were masked to treatment assignment.

Initially 1081 enrolled and randomised but 4 excluded as had glaucoma so not included in intention to treat analysis.
Dropouts due to adverse events:Group 1: 116/536 (21.7%)
Group 2: 51/541 (9.4%)
OR: 2.54 (95% CI: 1.83–3.53)
Development of reproducible VF defect or glaucomatous change of optic disc:Group 1: 46/536
Group 2: 60/541
OR: 0.86 (95% CI: 0.58–1.26)
p value: 0.45
Mean IOP at follow up6 months
Group 1: 20 ± 2.69 (n=484)
Group 2: 21.3 ± 2.98 (n=492)

12 months
Group 1: 19.7 ± 2.88 (n=453)
Group 2: 21 ± 3.41 (n=475)

2 years
Group 1: 19.1 ± 2.85 (n=391)
Group 2: 20.4 ± 3.35 (n=447)

5 years
Group 1: 18.2 ± 3.45 (n=192)
Group 2: 19.1 ± 3.71 (n=217)
Mean % reduction from baseline in observed cases:6 Months
Group 1: 14.5%
Group 2: 9.3%

5 years:
Group 1: 22.1%
Group 2: 18.7%
Mean % reduction IOP from baseline in last observation carried forward analysis: (5 years)Group 1: 17.9% (SD 14.1%)
Group 2: 13.7% (SD 15.9%)
Safety endpoint (IOP 35mmHg or greater):Group 1: 1/536 (0.2%)
Group 2: 12/541 (2.2%)

Abbreviations: NR=not reported, M/F=male/female, NA=not applicable, N=total number of patients randomised, SD=Standard Deviation, CI95%= 95% Confidence Interval, ITT=Intention to Treat

From: Appendix D, Evidence tables

Cover of Glaucoma
Glaucoma: Diagnosis and Management of Chronic Open Angle Glaucoma and Ocular Hypertension.
NICE Clinical Guidelines, No. 85.
National Collaborating Centre for Acute Care (UK).
Copyright © 2009, National Collaborating Centre for Acute Care.

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