Trends in mortality and medical spending in patients hospitalized for community-acquired pneumonia: 1993-2005.
BACKGROUND
Community-acquired pneumonia (CAP) is the most common infectious cause of death in the United States. To understand the effect of efforts to improve quality and efficiency of care in CAP, we examined the trends in mortality and costs among hospitalized CAP patients.


METHODS
Using the National Inpatient Sample between 1993 and 2005, we studied 569,524 CAP admissions. The primary outcome was mortality at discharge. We used logistic regression to evaluate the mortality trend, adjusting for age, gender, and comorbidities. To account for the effect of early discharge practices, we also compared daily mortality rates and performed a Cox proportional hazards model. We used a generalized linear model to analyze trends in hospitalization costs, which were derived using cost-to-charge ratios.


RESULTS
Over time, length of stay declined, while more patients were discharged to other facilities. The frequency of many comorbidities increased. Age/gender-adjusted mortality decreased from 8.9% to 4.1% (P < 0.001). In multivariable analysis, the mortality risk declined through 2005 (odds ratio, 0.50; 95% confidence interval, 0.48-0.53), compared with the reference year 1993. The daily mortality rates demonstrated that most of the mortality reduction occurred early during hospitalization. After adjusting for early discharge practices, the risk of mortality still declined through 2005 (hazard ratio, 0.74; 95% confidence interval, 0.70-0.78). Median hospitalization costs exhibited a moderate reduction over time, mostly because of reduced length of stay.


CONCLUSIONS
Mortality among patients hospitalized for CAP has declined. Lower in-hospital mortality at a reduced cost suggests that pneumonia is a case of improved productivity in health care.
Department of Internal Medicine, University of Chicago, Chicago, IL, USA. gruhnke@medicine.bsd.uchicago.edu
Gregory W
GW
Ruhnke
Marcelo
M
Coca-Perraillon
Barrett T
BT
Kitch
David M
DM
Cutler
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017714:Community-Acquired Infections / Q000191:economics* / Q000401:mortality* / Q000628:therapy; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D007902:Length of Stay / Q000191:economics* / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000191:economics* / Q000401:mortality* / Q000628:therapy; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology