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U.S. Department of Health and Human Services

522 Postmarket Surveillance Studies

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CENTER FOR DEVICES AND RADIOLOGICAL HEALTH

DIVISION OF EPIDEMIOLOGY

"PROTECTING & PROMOTING PUBLIC HEALTH THROUGH DEVICE SURVEILLANCE AND RESEARCH"



WELCOME TO THE 522 POSTMARKET SURVEILLANCE STUDIES WEBPAGE

 

 

 

 

            

Microbial Keratitis Study


 
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General
Study Status Completed
522 Number / Requirement Number PS060002 / PSS001
Date Current Plan Accepted 07/03/2007
Study Name Microbial Keratitis Study
Root Document Number P870024/S043  P010062/S001 
General Study Protocol Parameters
Study Design Retrospective Cohort Study
Data Source New Data Collection
Comparison Group Objective Performance Criterion
Analysis Type Analytical
Study Population Child: 2-12 yrs, Adolescent: 13-18 yrs, Transit. Adolescent B (as adults) : 18-21 yrs, Adult: >21
Detailed Study Protocol Parameters
Study Design Description 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..

Study Population Description Patient information from a stratified sample of 200 practitioners.

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%).

Data Collection 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.

Follow-up Visits and Length of Follow-up Retrospective assessment of available visits

Interim or Final Data Summary
Actual Number of Patients Enrolled 1,317 patients were enrolled

Actual Number of Sites Enrolled 86 sites were enrolled

Patient Followup Rate N/A
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.

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).

Study Strengths and Weaknesses The retrospective study design does not employ patient enrollment but rather the selection of practitioners.
Recommendations for Labeling Changes Labeling changes not recommended.



Microbial Keratitis Study Schedule

Report Schedule
Report
Date Due
FDA Receipt
Date
Applicant's Reporting Status
2-year final report 07/10/2009 07/10/2009 On Time


  • The 522 Postmarket Surveillance Studies Program encompasses design, tracking, oversight, and review responsibilities for studies mandated under section 522 of the Federal Food, Drug and Cosmetic Act. The program helps ensure that well-designed 522 postmarket surveillance (PS) studies are conducted effectively and efficiently and in the least burdensome manner.
  • In May 2008, the oversight responsibility of the 522 Postmarket Surveillance Studies Program was transferred to the Division of Epidemiology (DEPI) of the Office of Surveillance and Biometrics (OSB)/Center for Devices and Radiological Health (CDRH). DEPI continues to build the 522 program.
  • CDRH has established an automated internal tracking system that efficiently identifies the reporting status of active 522 PS studies based on study timelines incorporated in study protocols and agreed upon by the CDRH and applicants. This system represents CDRH's effort to ensure that all 522 PS commitments are fulfilled in a timely manner.
  • In addition, CDRH launched this publicly available webpage to keep all stakeholders informed of the progress of each 522 PS study. The webpage displays general information regarding each study, as well as the overall study status (based on protocol-driven timelines and adequacy of the data) and the applicant's reporting status for each submission due.

Links

Contact Information

Cheryl Reynolds
Project Manager, 522 Postmarket Surveillance (PS) Studies Program
Food and Drug Administration
10903 New Hampshire Ave
WO66-2252
Silver Spring, MD 20993-0002

Phone: (301) 796-6068
Fax: (301) 847-8140
Cheryl.Reynolds@fda.hhs.gov
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