Morbidity and mortality among newly hospitalized patients with community-acquired pneumococcal bacteremia: a retrospective cohort study in three teaching hospitals in Japan.

AIM: Although the mortality rate of pneumococcal bacteremia has been intensively studied, few studies have examined how it influences patient morbidity. This study aimed to fill this research gap by clarifying the impact of pneumococcal bacteremia on mortality and morbidity.

METHODS

We carried out a retrospective cohort study of adult patients hospitalized with community-acquired pneumococcal bacteremia in three teaching hospitals in Japan from January 2003 to December 2010. Morbidity was defined as a worsening Katz Index score compared with that before infection onset, new impairment of oral intake or new requirement for oxygen assistance at discharge.

RESULTS

Of 135 patients identified (mean age 70 years; 38% female), 116 (86%) were able to carry out activities of daily living independently before the onset of the infection. Pneumonia was found to be the most common infective source (69%), followed by meningitis (10%) and septic arthritis or vertebral osteomyelitis (8.1%). The 14-day, 30-day, and inpatient mortality rates were found to be 15%, 20% and 25%, respectively. The morbidity at discharge was 26 out of 101 (26%) among all survivors and 18 out of 42 (43%) among survivors who were aged ≥ 75 years. Multivariate analysis showed that an age of ≥ 75 years is an independent predictor of morbidity (adjusted odds ratio 16.3, 95% CI 2.0-135.9).

CONCLUSIONS

Our study showed that a high proportion of inpatient morbidity and mortality occurs in adult patients with pneumococcal bacteremia, especially among those aged ≥ 75 years.