PURPOSE: Pneumococcal vaccine has increased the relative incidence of non-vaccine serotypes. After an outbreak of serotype 5 IPD (2006-2007), we studied outcomes associated with this non-vaccine serotype.
METHODS: Patients admitted for IPD to 2 hospitals in Vancouver before and during the outbreak (July 1/04 - June 30/07) were identified by serotyping. Clinical descriptors were abstracted from medical records and regression was used to associate serotype status (5 versus non-5) with outcomes.
RESULTS: Among 255 hospitalized IPD patients (149 serotype 5, 106 non-5), the serotype 5 group was younger than non-5 (mean age 44 vs 52; p<0.0001), more likely to report intravenous drug abuse (45% vs 23%; p=0.0003), smoking (85% vs 62%; p<0.0001) and crack cocaine use (53% vs 21%; p<0.0001), and less likely to have comorbidities (48% vs 75%; p<0.0001). The serotype 5 group had a lower prevalence of necrotizing pneumonia (3% vs 9%; p=0.04) but there was no difference in prevalence of empyema. Hospital mortality was lower in the serotype 5 group than in the non-5 group (11% vs 32%; p<0.0001). After adjustment for age, sex, substance abuse, and comorbidities, serotype 5 was not associated with risk of ICU admission, but was associated with lower hospital mortality (OR 0.32; CI 0.15-0.66). 71 IPD patients (41 serotype 5, 30 non-5) were admitted to ICU. After adjustment for the same variables plus APACHE II score, the serotype 5 group had a higher incidence of vasopressor use (OR 13.9; CI 2.9-67.6). No statistically significant differences between groups were found in use of chest tubes or dialysis, or in ventilator days, ICU days, or ICU mortality.
CONCLUSION: Compared to IPD due to other serotypes, serotype 5 is associated with younger age, more substance abuse, fewer comorbidities, and lower hospital mortality. Despite more use of vasopressors in ICU, there was no association with other life supports or ICU outcomes.
CLINICAL IMPLICATIONS: Knowledge of serotype in IPD may assist in anticipation of hospital and ICU utilization and outcomes.
DISCLOSURE: Joanna Zurawska, No Financial Disclosure Information; No Product/Research Disclosure Information