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Study Title and Description

Comparison of polyhexamethylene biguanide and chlorhexidine as monotherapy agents in the treatment of Acanthamoeba keratitis.



Key Questions Addressed
1 What are the medical interventions for acanthamoeba keratitis?
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Primary Publication Information
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TitleData
Title Comparison of polyhexamethylene biguanide and chlorhexidine as monotherapy agents in the treatment of Acanthamoeba keratitis.
Author Lim N., Goh D., Bunce C., Xing W., Fraenkel G., Poole TR., Ficker L.
Country Moorfields Eye Hospital, London, United Kingdom. natashalim1@aol.com
Year 2008
Numbers Pubmed ID: 17996208

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Medical interventions for acanthamoeba keratitis 2015
Arms
Number Title Description Comments
1 Chlorhexidine 0.02% Chlorhexidine 0.02% eye drops (Moorfields Pharmaceuticals), administered hourly day and night for first 2 days, hourly by day for next 5 days, then tapering to 4 times daily based on clinical response. Adjunctive therapy with topical steroids, topical cycloplegics, oral nonsteroidal anti-inflammatory agents, or a combination of these, based on clinical need.
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2 Polyhexamethylene biguanide 0.02% Polyhexamethylene biguanide 0.02% eye drops (Moorfields Pharmaceuticals), administered hourly day and night for first 2 days, hourly by day for next 5 days, then tapering to 4 times daily based on clinical response. Adjunctive therapy with topical steroids, topical cycloplegics, oral nonsteroidal anti-inflammatory agents, or a combination of these, based on clinical need.
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Design Details
Question... Follow Up Answer Follow-up Answer
Study design parallel-group randomized controlled trial
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Number randomized 56 eyes of 55 participants: 30 eyes in chlorhexidine group and 26 eyes in polyhexamethylene biguanide (PHMB) group
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Exclusions after randomization 3 eyes of 3 participants: 1 eye in chlorhexidine group and 2 eyes in PHMB group
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Losses to follow-up 2 eyes of 2 participants: 1 eye in chlorhexidine group and 1 eye in PHMB group
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Number analyzed 51 eyes of 50 participants 28 eyes in chlorhexidine group 23 eyes in PHMB group
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Unit of analysis mostly one study eye per participant (51 eyes of 50 participants)
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Sample size or power calculation none reported
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Unusual study design 2 eyes of 1 participant enrolled and analyzed separately without taking into account of non-independence
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Country United Kingdom
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Median age 31 years (IQR, 24 to 36) 31 years (IQR 23 to 36) for chlorhexidine group 29 years (IQR 24 to 37) for PHMB group
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Gender 27/51 (53%) women and 24/51 (47%) men: 13/28 (46.4%) women and 15/28 (53.6%) men in chlorhexidine group 14/23 (60.1%) women and 9/23 (39.9%) men in PHMB group
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Inclusion criteria "clinical diagnosis of Acanthamoeba keratitis at Moorfields Eye hospital between February 1, 1995 and May 30, 2001"; "when microbiology culture results were negative or when corneal biopsy was not performed, cases were included in the study if there was a history of contact lens wear supported by specific clinical findings suggestive of Acanthamoeba keratitis such as: 1) the presence of perineural infiltrates, 2) ring infiltrates, or 3) keratitis with disproportionate pain"
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Exclusion criteria "any other form of microbial keratitis not considered to be Acanthamoeba keratitis at the time of presentation"
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Equivalence of baseline characteristics yes
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Intervention 1 chlorhexidine 0.02% eye drops (Moorfields Pharmaceuticals)
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Intervention 2 polyhexamethylene biguanide 0.02% eye drops (Moorfields Pharmaceuticals)Both treatments administered hourly day and night for first 2 days, hourly by day for next 5 days, then tapering to 4 times daily based on clinical response. Adjunctive therapy with topical steroids, topical cycloplegics, oral nonsteroidal anti-inflammatory agents, or a combination of these, based on clinical need.
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Length of follow-up Planned: not reported Actual: not reported
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Primary outcome, as defined treatment failure, defined as "failure to induce a favorable clinical response within two weeks of initiating treatment with PHMB or chlorhexidine alone" as well as "all patients whose infection worsened while receiving a monotherapy trial drug"
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Secondary outcomes, as defined "recovery of visual acuity", degree of corneal scarring (scale of 0 = no scarring to 4 = 4 quadrants with corneal scarring), and the need for penetrating keratoplasty
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Other outcomes disease resolution, subjectively assessed as control of ocular inflammation, relief of pain and photosensitivity, and recovery of vision; adverse events
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Intervals at which outcomes assessed not reported
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Study period 1 February 1995 to 30 May 2001
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Funding sources not reported
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Declarations of interest "The authors indicate no financial support or financial conflict of interest"
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Reported subgroup analyses no
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Random sequence generation (selection bias):Authors' judgement Low risk
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Random sequence generation (selection bias):Support for judgement "Standard randomization sheets for clinical trials that existed before computer-generated randomization tables were created by the Moorfields Pharmacy at the time of the trial and were used for the randomization sequence."
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Allocation concealment (selection bias):Authors' judgement Low risk
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Allocation concealment (selection bias):Support for judgement "Patients were allocated a sequential number from the randomization sheets."
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Masking of participants and personnel (performance bias):Authors' judgement Low risk
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Masking of participants and personnel (performance bias):Support for judgement "The medication bottles were labelled either drug A (for chlorhexidine) or drug B (for PHMB)." "Both patients and the team of doctors involved in this study were masked to the contents of drug A or drug B until the end of the study."
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Masking of outcome assessors and data analyzers (detection bias):Authors' judgement Low risk
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Masking of outcome assessors and data analyzers (detection bias):Support for judgement "Both patients and the team of doctors involved in this study were masked to the contents of drug A or drug B until the end of the study."
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Incomplete outcome data (attrition bias):Authors' judgement Low risk
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Incomplete outcome data (attrition bias):Support for judgement Overall, data missing for 5/56 (9%) eyes; 2/30 (7%) in the chlorhexidine group (1 enrolled by pharmacy by error and 1 lost to follow-up) and 3/26 (11.5%) in the PHMB group (1 misdiagnosed; 1 non-compliant with medication; and 1 lost to follow-up).
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Selective reporting (reporting bias):Authors' judgement Unclear risk
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Selective reporting (reporting bias):Support for judgement No protocol or clinical trial registration identified. Outcomes listed in methods section of published paper were reported in the results section.
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Other bias:Authors' judgement Low risk
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Other bias:Support for judgement None identified.
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How were missing data handled? excluded from analysis
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Results & Comparisons


Results Data
Outcome: Resolution of infection      Population: All Participants
Time Point Measure Chlorhexidine 0.02% Polyhexamethylene biguanide 0.02%


N/A years

N Analyzed 28 23
Mean 86% 78%
SD
SE
Outcome: Visual acuity      Population: All Participants
Time Point Measure Chlorhexidine 0.02% Polyhexamethylene biguanide 0.02%


N/A years

N Analyzed 28 23
Counts 20 Better; 5 Same; 3 Worse 13 Better; 6 Same; 4 Worse
Outcome: Additional therapy      Population: All Participants
Time Point Measure Chlorhexidine 0.02% Polyhexamethylene biguanide 0.02%


N/A years

N Analyzed 28 23
Mean 7% 13%
SD
SE

Adverse Events
Arm or Total Title Description Number of events Comments
Chlorhexidine 0.02% Stinging sensation and superficial punctuate keratopathy
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Polyhexamethylene biguanide 0.02%
Total 8