TABLE 2.
Pneumococcal phenotype associations with otitis media progression
| Pneumococcal attributea | Relative progression rate, per 1 SD increase in covariate (95% CI)b | Adjusted relative progression, per 1 SD increase in covariate (95% CI)b,c | Adjusted relative increase in progression rate, per 1 SD increase in covariate, for S. pneumoniae plus NTHi (95% CI)b |
|---|---|---|---|
| Metabolic efficiency (18) | |||
| S. pneumoniae only | 1.51 (1.32, 1.74) | 1.50 (1.31, 1.72) | Ref. |
| S. pneumoniae plus NTHi | 1.09 (0.96, 1.25) | 1.07 (0.94, 1.22) | 0.72 (0.59, 0.86) |
| Surface anionic charge (19) | |||
| S. pneumoniae only | 1.02 (0.95, 1.10) | 1.03 (0.95, 1.11) | Ref. |
| S. pneumoniae plus NTHi | 0.80 (0.72, 0.89) | 0.79 (0.71, 0.88) | 0.77 (0.68, 0.88) |
| Resistance to neutrophil-mediated killing (18) | |||
| S. pneumoniae only | 1.05 (0.93, 1.19) | 1.04 (0.92, 1.16) | Ref. |
| S. pneumoniae plus NTHi | 1.07 (0.94, 1.21) | 1.05 (0.93, 1.20) | 1.02 (0.85, 1.21) |
| Capsule width (18) | |||
| S. pneumoniae only | 0.87 (0.78, 0.98) | 0.87 (0.77, 0.97) | Ref. |
| S. pneumoniae plus NTHi | 0.81 (0.72, 0.91) | 0.80 (0.71, 0.90) | 0.93 (0.78, 1.09) |
| Case-fatality ratio in IPD (20) | |||
| S. pneumoniae only | 0.71 (0.63, 0.81) | 0.71 (0.63, 0.81) | Ref. |
| S. pneumoniae plus NTHi | 0.73 (0.64, 0.84) | 0.74 (0.65, 0.85) | 1.04 (0.86, 1.25) |
| Invasiveness (IPD per carriage episode) (21) | |||
| S. pneumoniae only | 1.15 (1.02, 1.30) | 1.14 (1.01, 1.29) | Ref. |
| S. pneumoniae plus NTHi | 1.12 (0.99, 1.26) | 1.11 (0.99, 1.25) | 0.97 (0.82, 1.15) |
Pneumococcal attributes are defined in Table 1.
Progression rates were compared via the odds ratio, as calculated by logistic regression with an exchangeable correlation structure to account for repeated carriage observations from individual children. Due to collinearity among serotype measurements, individual models are fitted for each association. Our derivation of the odds ratio as the relative progression rate is described in Materials and Methods. Boldface type indicates two-sided P < 0.05 in a model fitted with generalized estimating equations to account for repeated sampling of children.
Models were controlled for Jewish/Bedouin ethnicity and respiratory virus season (December to March).