The findings of the current study demonstrate that the underutilization of pneumococcal vaccination among community-dwelling Medicare-eligible older African Americans may be explained by the racial variation in the receipt of influenza vaccination, but not by the traditional confounders of racial disparity such as imbalances in education, income, or morbidity burden. Because utilizations of influenza and pneumococcal vaccinations are closely related and may reflect patients’ and providers’ attitudes toward prevention and vaccination, these findings suggest that utilization of pneumococcal vaccination among older African Americans may be improved by improving patients’ and providers’ attitudes toward vaccination, in general, and by improving utilization of influenza vaccination in particular.
The low rate of utilization of pneumococcal vaccination in community-dwelling Medicare-eligible older adults is rather surprising. Pneumococcal vaccine is recommended for adults ≥65 years and has been covered by Medicare since 1981. The vaccine is effective in reducing the incidence and severity of invasive pneumococcal disease,_is generally well-tolerated and is usually a single-dose vaccination.6, 11–16
One potential explanation for the underutilization of pneumococcal vaccination may be the lack of awareness of the danger of pneumococcal disease and of the benefits of pneumococcal vaccination in apparently healthy older adults. The lack of awareness as a potential reason for underutilization is supported by our observation of increased odds of pneumococcal vaccination among those with chronic obstructive pulmonary disease and prior pneumonia.
The unadjusted association between African American race and the receipt of pneumococcal vaccination may in part be explained by the imbalances in key baseline socio-demographic characteristics including education and income.17–20
For example, a higher proportion of African American older adults in our study had lower education and lower income than their white counterparts. Although the pneumococcal vaccination is fully covered by Medicare, it may still be underutilized by older adults with lower income due to limitations related to access to care and transportation. Older adults with lower education are likely to have lower health literacy and would thus be less likely to understand and accept preventive measures such as vaccination. However, findings from our multivariable model suggest that education, income and other important socio-demographic variables do not fully account for the significant underutilization of pneumococcal vaccination among African American older adults. 21, 22
Lack of contact with health-care providers or missed opportunities to vaccinate during contact have been suggested as reasons for underutilization of vaccination.15, 23–26
In particular, doctors’ recommendations for vaccination have been shown to positively influence patients’ decision to be vaccinated.4, 27
This is consistent with our observation that hypertension and arthritis, the two most common morbidities among older adults,28
were associated with increased odds of pneumococcal vaccination. Older adults with these conditions are likely to have more frequent visits with health-care providers, which may increase the opportunity for vaccination.
The loss of the significant bivariate association between race and pneumococcal vaccination after the singular adjustment for influenza vaccination suggests that this association can be explained by the racial imbalance in the utilization of influenza vaccination. The role of influenza vaccination as a confounder is evident from its strong association with both the exposure (race) and outcome (pneumococcal vaccination) in our study ( and ). Because, unlike the pneumococcal vaccination, the influenza vaccination is offered annually and may be a better marker for patients’ and physicians’ attitudes and practices toward vaccination as a preventive measure, older adults who receive influenza vaccinations may also be more likely to receive pneumococcal vaccination.
Underutilization of pneumococcal vaccines, in general, and by age, sex, race, and regional variation in particular have been previously described.3–5, 13, 15, 27, 29, 30
However, to the best of our knowledge, this is the first report of a detailed analysis of race-related underutilization of the pneumococcal vaccine that provides insights into potential underlying reasons for the racial variation in the utilization of pneumococcal vaccination. These findings have significant public health and clinical implications. Pneumococcal pneumonia is the most common cause of community-acquired pneumonia, with mortality as high as 50% and being responsible for 25–35% pneumonia-related hospitalizations.1, 2
It is important to note that concomitant bacteremia occurs in about 10–25% of elderly patients who have pneumococcal pneumonia, which is associated with poor prognosis, but may be reduced by pneumococcal vaccination. The incidence of bacteremia is 3–5 fold higher among African Americans,31, 32
which further highlights the importance for improving the utilization of pneumococcal vaccination for older African Americans.
Several limitations of our study must be acknowledged. CHS participants were recruited between 1989 and 1993 and the rate of pneumococcal vaccination has improved since that time. However, racial disparity in the use of pneumococcal vaccination persists.3, 33, 34
According to the CDC, in 2008 while the overall rate for pneumococcal vaccination among older adults was about 60%, it was about 44% for older African Americans.33
Therefore, despite the age of the dataset, these findings are still relevant and may provide important insight for improvement of pneumococcal vaccination rates among contemporary older adults. Another limitation of this study is the potential for recall bias because pneumococcal vaccination use was self reported. While it would be ideal to verify self-reports with chart review or claims data, self-report remains the method of choice for collection of such data at the national level.3, 33, 34
Finally, site specific enrollment information was unavailable for the CHS, therefore potential differences by site of enrollment could not be evaluated.
In conclusion, the underutilization of pneumococcal vaccination by older African Americans is more likely due to racial variation in the utilization of influenza vaccination, and less likely due to traditional confounders of racial disparity such as racial imbalances in education and/or income. These findings provide important insights into the racial disparity in the utilization of pneumococcal vaccination that persists despite overall improvement in the utilization of pneumococcal vaccination.