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| General |
| Study Status |
Completed |
| 522 Number / Requirement Number |
PS060002 / PSS001 |
| Date Original Plan Accepted |
07/03/2007
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| Date Current Plan Accepted |
07/03/2007
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| Study Name |
Microbial Keratitis Study
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| Device Name |
Paragon crt 100 lens and boston vision shaping treatment (vst) lens for ook
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| Root Document Number |
P870024/S043
P010062/S001
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| General Study Protocol Parameters |
| Study Design |
Retrospective Cohort Study
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| Data Source |
New Data Collection
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| Comparison Group |
Objective Performance Criterion
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| Analysis Type |
Analytical
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| Study Population |
Child: 2-12 yrs,
Adolescent: 13-18 yrs,
Transit. Adolescent B (as adults) : 18-21 yrs,
Adult: >21
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| Detailed Study Protocol Parameters |
| Study Objectives |
The study is a retrospective study design where a randomly selected, stratified sample of 200 practitioners were identified to determine their patients fit with duration of lens wear, and establish the presence or absence of a history of microbial keratitis.
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| Study Population |
Patient information from a stratified sample of 200 practitioners.
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| Sample Size |
Statistical power dependent on MK incidence rate in children and the sample size obtained. Non-inferiority limits of between 0.006 and 0.01 are used to assess non-inferiority, depending on the underlying MK incidence rate. With a sample size of 2000 patient years (1000 juveniles and 1000 adults), there is > 80% power to show non-inferiority using a non-inferiority limit of 0.01 (1 in 100), assuming the common incidence rate for juveniles and adults is no worse than 1 in 150. With a sample size of 2000 patient-years (1000 juveniles and 1000 adults), there is > 80% power to show non- inferiority using the stricter non-inferiority limit of 0.006, assuming the common incidence rate for juveniles and adults is no worse than 1 in 500 (0.2%).
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| Key Study Endpoints |
The primary endpoints were as follows: The incidence of microbial keratitis in pediatric and adult patients, and The difference in risk between the two age groups.
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| Follow-up Visits and Length of Follow-up |
Retrospective assessment of available visits
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| Interim or Final Data Summary |
| Actual Number of Patients Enrolled |
1,317 patients were enrolled
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| Actual Number of Sites Enrolled |
86 sites were enrolled
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| Patient Followup Rate |
N/A
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| Final Safety Findings |
The overall estimated incidence of microbial keratitis is 0.00077 per patient year (90% CI: 0.00014, 0.00243) or 7.7 per 10,000 years (90% CI: 1.4, 24.3). For children, the estimated incidence of microbial keratitis is 0.00140 per patient year (90% CI: 0.00025, 0.00441) or 14.0 per 10,000 years (90% CI: 2.5, 44.1). For adults, the estimated incidence of microbial keratitis is 0.0 per patient year (90% CI: 0, 0.00264) or 0 per 10,000 years (90% CI: 0, 26.4). The rate ration for children and adults assuming continuiity correction based on at least three months and twelve months wear are 4.06 (95 CI: 0.19-84.41), 3.88 ( 95% CI: 0.19-80.80), respectively.The confidence limits of the relative risk estimates include 1, which show there is no statistical difference between the rate observed in pediatrics and the rate observed in adults. The 95%CIs show the rate ratio can go as low as 0.2 and as high as 84. This can be considered a wide confidence interval. However, the study was adequately powered to detect a difference between adults and pediatrics, if one existed. The study did not pick up a sufficient number of events to be statistically significant, thus it is reasonable to conclude that there is not a meaningful difference.
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| Final Effectiveness Findings |
The overall estimated incidence of microbial keratitis is 0.00077 per patient year (90% CI: 0.00014, 0.00243) or 7.7 per 10,000 years (90% CI: 1.4, 24.3).
For children, the estimated incidence of microbial keratitis is 0.00140 per patient year (90% CI: 0.00025, 0.00441) or 14.0 per 10,000 years (90% CI: 2.5, 44.1).
For adults, the estimated incidence of microbial keratitis is 0.0 per patient year (90% CI: 0, 0.00264) or 0 per 10,000 years (90% CI: 0, 26.4).
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| Study Strengths and Weaknesses |
The retrospective study design does not employ patient enrollment but rather the selection of practitioners.
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| Recommendations for Labeling Changes |
Labeling changes not recommended.
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