Am J Med. 2011 Feb;124(2):171-178.e1. doi: 10.1016/j.amjmed.2010.08.019.

Marked reduction in 30-day mortality among elderly patients with community-acquired pneumonia.

Ruhnke GW, Coca-Perraillon M, Kitch BT, Cutler DM.

Source

Section of Hospital Medicine, University of Chicago, IL 60637, USA. gruhnke@medicine.bsd.uchicago.edu

Abstract

BACKGROUND:

Community-acquired pneumonia is the most common infectious cause of death in the US. Over the last 2 decades, patient characteristics and clinical care have changed. To understand the impact of these changes, we quantified incidence and mortality trends among elderly adults.

METHODS:

We used Medicare claims to identify episodes of pneumonia, based on a validated combination of diagnosis codes. Comorbidities were ascertained using the diagnosis codes located on a 1-year look back. Trends in patient characteristics and site of care were compared. The association between year of pneumonia episode and 30-day mortality was then evaluated by logistic regression, with adjustment for age, sex, and comorbidities.

RESULTS:

We identified 2,654,955 cases of pneumonia from 1987-2005. During this period, the proportion treated as inpatients decreased, the proportion aged ≥80 years increased, and the frequency of many comorbidities rose. Adjusted incidence increased to 3096 episodes per 100,000 population in 1999, with some decrease thereafter. Age/sex-adjusted mortality decreased from 13.5% to 9.7%, a relative reduction of 28.1%. Compared with 1987, the risk of mortality decreased through 2005 (adjusted odds ratio, 0.46; 95% confidence interval, 0.44-0.47). This result was robust to a restriction on comorbid diagnoses assessing for the results' sensitivity to increased coding.

CONCLUSIONS:

These findings show a marked mortality reduction over time in community-acquired pneumonia patients. We hypothesize that increased pneumococcal and influenza vaccination rates as well as wider use of guideline-concordant antibiotics explain a large portion of this trend.