Predictors of pneumococcal polysaccharide vaccination among patients at three inner-city neighborhood health centers.

BACKGROUND: Despite the availability of pneumococcal polysaccharide vaccine (PPV), vaccination rates are modest, and racial disparity in these rates is known to occur.
OBJECTIVE: The purpose of this study was to identify determinants of patient-reported receipt of PPV among patients from 3 inner-city health centers that serve large numbers of minority and disadvantaged patients.
METHODS: In 2003, a random sample of patients from 3 inner-city health centers was surveyed by computer-assisted telephone interview concerning their vaccination status and their attitudes and beliefs about PPV. The questionnaire was based on the theory of reasoned action, which emphasizes the contributions to behavioral intention of cognitive beliefs (including the likelihood of consequences), the value of those consequences, and normative beliefs. Factor analysis was conducted to examine whether survey items specific to attitudes about PPV would group together; the variance of the components resulting from the factor analysis was expressed in eigenvalues. Logistic regression analyses were conducted to determine which factors, demographic characteristics, and health habits were independently associated with PPV status.
RESULTS: Of 674 patients sent introductory letters (13 of whom were ineligible), 325 (49%) completed the interview with usable data. These patients were primarily aged > or = 65 years (52% [168/325]), female (69% [223/325]), and white (57% [174/306]), and had an annual household income < 20,000 dollars (61% [174/287]). Vaccination status or intention to be vaccinated was unknown for 25 persons, reducing the sample to 300. Of these respondents, 59% (178) reported vaccination, 9% (26) intended to be vaccinated within 6 months, and 32% (96) had no intention of being vaccinated. Vaccination rates were 76% (119/157) for responders aged > or = 65 years and 41% (59/143) for responders aged 50 to 64 years (P < 0.001). Logistic regression analyses found 3 variables that were significantly associated with the likelihood of vaccination: age > or = 65 years; frequency of physician visits; and timing of the last complete physical examination. The factor analysis with varimax rotation identified 2 factors that increased the likelihood of reporting ever receiving PPV: attitudes about PPV and social influences (eigenvalue = 2.69), and beliefs about pneumonia risk and vaccine efficacy (eigenvalue = 1.24). When these factors were added to the model, the effects of age and frequency of seeing a physician became nonsignificant. Compared with those having a complete physical examination < 1 year ago, those having an examination 1 to 2 years ago (odds ratio [OR] = 0.16; 95% CI = 0.04-0.69) or > 2 years ago (OR = 0.10; 95% CI = 0.01-0.78) were less likely to be vaccinated. Those agreeing with the attitudes and social influence factor were more likely to be vaccinated (OR = 8.24; 95% CI = 3.97-17.12), as were those agreeing with the pneumonia risk and vaccine efficacy factor (OR = 2.63; 95% CI = 1.20-5.80).
CONCLUSIONS: Attitudes about vaccination and a clinician's recommendation are the most powerful predictors of PPV status. Efforts to raise rates of vaccination and reduce racial disparities should emphasize communication of clinicians' recommendations to patients.