 | The 131st Annual Meeting (November 15-19, 2003) of APHA |
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| The 131st Annual Meeting (November 15-19, 2003) of APHA |
AtoZ(Etsuji) Okamoto, MD, Department of Technology Assessment & Biostatistics, Systematic Review Section, National Institute of Public Health, 2-3-6, Minami, Wako-shi, Saitama, 351-0197, Japan, +81-48-458-6111(x2715), atoz@niph.go.jp
[Background] Effectiveness of vaccination will be best evaluated by way of randomized controlled trials (RCT). However, such prospective intervention may not be feasible in community setting because RCT is not indicated for procedures with proven effectiveness for ethical problems. The author attempted to assess the effectiveness of FLU vaccination for the elderly using only retrospective data with due consideration to the limitations of nonrandomized controlled study. [Data and Method] The data are health insurance claims (claims) submitted to the national health insurance program run by a suburban city in Japan. All claims submitted in February 2002 for elderly were matched with the recipient list of FLU vaccination program provided by the city during October thru December 2001. The number of outpatient visits with definite diagnoses of FLU was used as outcome to assess the effectiveness of vaccination. To adjust health status between vaccinated and non-vaccinated population, the effectiveness was assessed comparing the percent of outpatient visits for FLU against the total number of outpatient visits in both groups thereby overcoming the potential biases involving non-randomized controlled study. [Results] Of 10,530 elderly population, 3214 or 30.5% were vaccinated. From the vaccinated group, 3,589 claims with 8,642 outpatient visits were submitted while 6,302 claims with 13,060 visits were from the non-vaccinated 7,316 elderly. The number of outpatient visits was 0.053% of total visits in the vaccinated group as opposed to 0.319% in the non-vaccinated group yielding the effectiveness of vaccination of 83.6%. [Discussion] The finding was consistent with those from RCTs. Assessment using only retrospective data is able to replace RCTs if the potential bias of health status is appropriately adjusted.
Learning Objectives:
Keywords: Prevention, Assessments
Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.