Table 2

Logistic regression of the most important predictors of pneumococcal vaccination among older adults with clinically diagnosed community-acquired pneumonia and sent for confirmatory x-rays (n = 1811).

Predictors of Pneumococcal Vaccination

Adjusted Odds Ratio2

95% Confidence Interval


Most recent influenza vaccine:

One year or more/never

1.00

-

Less than one year ago

14.46

(4.27, 49.0)


How often in the last 6 months participant had a chat or did something with a friend:

Less than once/week

1.00

-

At least once/week

3.97

(1.71, 9.24)


Reported having health conditions in list3:

Reported none

1.00

-

Reported at least one

3.64

(1.60, 8.28)


Participant's age:

60 to 69

1.00

-

70 to 90

2.56

(1.21, 5.40)


Before illness, how much did your health problems limit your usual activities4:

Somewhat, very little, not at all

1.00

-

Quite a lot, could not do physical activities

5.37

(1.49, 19.31)


Amount of bodily pain4:

Mod/severe/very severe

1.00

-

None/very mild/mild

2.90

(1.25, 6.73)


How much spiritual values or religious faith plays a role in life:

None

1.00

-

Great deal to little

3.47

(1.03, 11.67)


Final Logistic Regression Model Statistics:

Rho-square = 0.25 (pseudo R2, values between 0.2 and 0.4 suggest a very good fit)

Cox & Snell R-square = .292; Nagelkerke R-square = .391 (i.e. between 29.2% and 39.1% of variance is explained by this model)

Hosmer and Lemeshow Goodness-of-Fit test = 0.948 (values greater than 0.25 indicate good fit)

74.6% correctly classified

1Four of the 185 (2.2%) participants had missing values for one or more of the variables included in the final model.

2Odds ratios for categorical variables represent comparisons with the referent group (OR = 1.00) after adjustment for all other variables in the model. An odds ratio greater than one indicates increased likelihood for pneumococcal vaccination. For example, participants aged 70 and older were 2.56 times more likely to report receiving the pneumococcal vaccination than participants 60 to 69 years of age (after adjusting for all other variables in the model).

3List included: food allergies, other allergies, asthma, chronic bronchitis, diabetes, emphysema, heart disease, congestive heart failure, cancer, liver disease, kidney disease, ever received a transplant, taking immunosuppressant drugs.

4Question from SF-8.

Krueger et al. BMC Geriatrics 2010 10:44   doi:10.1186/1471-2318-10-44

Open Data