Table 2.
Clinical characteristics of pneumococcal pneumonia patients grouped by immune response
| Group and characteristic | Positive immune responsea | Negative immune responsea | Total |
|---|---|---|---|
| All pneumococcal pneumonia patients | |||
| No. of patients in group | 28 | 34 | 62 |
| Mean age (yr) | 56 | 61 | 59 |
| No. (%b) of patients of male sex | 14 (50) | 17 (50) | 31 (50) |
| No. (%) of patients with one or more comorbid conditionsc | 11 (39) | 19 (56) | 30 (48) |
| Mean PSId on admission | 74e | 91 | 83 |
| No. (%) of patients with antibiotic use before admission | 6 (21) | 2 (6) | 8 (13) |
| No. (%) of patients with etiologic diagnosis by: | |||
| Blood culture | 8 (29) | 10 (29) | 18 (29) |
| Urine antigen test | 11 (39) | 17 (50) | 28 (45) |
| Sputum culture | 9 (32) | 7 (21) | 16 (26) |
| Mean duration of hospitalization (days) | 10e | 15 | 13 |
| No. (%) of patients who survived | 28 (100) | 34 (100) | 62 (100) |
| Pneumococcal pneumonia patients with identified serotype of infecting strain within antibody panel | |||
| No. of patients in group | 11 | 9 | 20 |
| Mean age (yr) | 50 | 55 | 52 |
| No. (%) of patients of male sex | 5 (45) | 8 (89) | 13 (65) |
| No. (%) of patients with one or more comorbid conditions | 4 (36) | 2 (22) | 6 (30) |
| Mean PSI on admission | 69 | 96 | 81 |
| No. (%) of patients with antibiotic use before admission | 1 (9) | 0 (0) | 1 (5) |
| No. (%) of patients with the following source of isolate: | |||
| Blood | 6 (55) | 8 (89) | 14 (70) |
| Sputum | 5 (45) | 1 (11) | 6 (30) |
| Mean duration of hospitalization (days) | 9 | 16 | 12 |
| No. (%) of patients who survived | 11 (100) | 9 (100) | 20 (100) |
a
Response was defined as at least a 2-fold increase in antibody concentrations with an end concentration above 0.35 μg/ml. The fold increase against a single pneumococcal serotype had to be at least two times greater than the fold increase against any other serotype.
b
Percentages are calculated from the number of patients within the response group.
c
Comorbid condition is one or more of the following: diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure, hepatic failure, renal failure, and malignancies.
d
PSI is described elsewhere (10).
e
Significant difference (P < 0.05) by Student's t test compared to negative immune response group.