Three Decades of Follow-up of Adults After Recovery From Invasive Pneumococcal Pneumonia

Abstract

Background: Streptococcus pneumoniae infection is the most common cause of community-acquired pneumonia in adults. Invasive pneumococcal disease (IPD) carries a high case fatality rate. We investigated the lifespan of adults who recovered from IPD during a 32-year follow-up.

Materials and methods: We determined whether adults discharged after an episode of IPD from hospitals affiliated with the Marshall University Joan C. Edwards School of Medicine in Huntington, West Virginia from 1983-2003 were alive on June 30, 2014. Lifespan was assessed by Kaplan-Meier methodology, Cox proportional hazards multivariate analysis, life expectancy using life tables for West Virginia, years of potential life lost and serotype occurrence.

Results: The study group comprised 155 adults who survived IPD. They had a mean age at discharge of 64.6 years, mean lifespan after IPD of 7.1 years, mean expected lifespan after IPD of 17.0 years, mean age at death of 71.6 years and a mean life expectancy of 81.6 years. Only 14 (9.0%) patients lived longer than their life expectancy. Of the 13 comorbid diseases analyzed, cancer and neurologic diseases and the number of comorbid diseases suffered by each patient were the significant variables associated with survival. The mean years of potential life lost was 9.936 years. Only serotype 12 of 31 serotypes recovered occurred more often in patients who survived for 11 or more years after discharge (relative risk = 3.44, 95% CI: 1.19-9.95).

Conclusions: The fact that most adult patients who recovered from IPD died before their documented life expectancy argues for the pernicious severity of IPD and the importance of immunization of adults with pneumococcal vaccines.

Keywords: Invasive pneumococcal infection; Life expectancy; Pneumonia; Streptococcus pneumoniae; Years of potential life lost.