Validation of self-report of influenza and pneumococcal vaccination status in elderly outpatients

Objective: To assess the validity of self-reported influenza and pneumococcal vaccination status. Design: Cross-sectional surveys of outpatients aged 65 years or older. Setting: A Veterans Affairs Medical Center (VA) and a community managed care organization (MCO). Both organizations have organized influenza and pneumococcal vaccination programs. Subjects: VA subjects included all elderly respondents to a mailed survey of 500 randomly selected outpatients. MCO subjects included all respondents to a telephone survey of 300 randomly selected elderly members of the MCO. Measurements: The VA survey was conducted following the 1995–1996 influenza season while the MCO survey was conducted following the 1994–1995 season. Self-report from the mailed survey for VA subjects and from the telephone survey for MCO subjects was compared to medical record documentation (paper and computerized combined). Results: The response rate was 77% (n = 369) for the VA subjects of whom 195 (53%) were aged 65 or older. The response rate for the MCO subjects was 84% (n = 237). Self-report of influenza vaccination had a sensitivity (SENS) of 1.0 and a specificity (SPEC) of .79 with a kappa of .72 (95% CI .58–.86) among VA patients. Among MCO patients, self-report of influenza vaccination had a SENS of .98 and a SPEC of .71 with kappa of .75 (95%CI .69–.89). Self-report of pneumococcal vaccination status among VA patients had a SENS of .97 and a SPEC of .53 with a kappa of .42 (95%CI .32–.52). Among MCO patients, self-report of pneumococcal vaccination had a SENS of .90 and a SPEC of .64 with a kappa of .54 (95%CI .40–.68). A secondary analysis excluding subjects living outside of the VA’s catchment area improved the specificity and indices of concordance of self-report of both influenza and pneumococcal vaccination. A secondary analysis of MCO data which excluded subjects who received a pneumococcal vaccination > 2 years prior to the study also improved concordance and the negative predictive value of self-report. Conclusions: Self-report of influenza vaccination is a highly sensitive and moderately specific measure. Self-report of pneumococcal vaccination is also a highly sensitive but less specific measure of vaccination status. Lower rates of validity for pneumococcal vaccination may reflect both less accurate recall, particularly for more distant vaccination, and less complete documentation in medical records.