Mortality Rate of Community-Acquired Pneumonia
Overall mortality from community-acquired pneumonia varies dramatically by disease severity and treatment setting: less than 1% for outpatients, approximately 7-11% for hospitalized patients, 18% for ICU patients, and 20-50% for severe CAP requiring intensive care. 1, 2, 3
Mortality by Treatment Setting
Outpatient Management
- Mortality is less than 1% in patients treated as outpatients 2
- These patients typically have CURB-65 scores of 0-1 4
Hospitalized Patients (Non-ICU)
- Overall hospitalized mortality ranges from 7-11% across large population-based studies 1, 3
- A three-state database analysis (Washington, Illinois, Florida) found mortality rates of 7.0%, 8.1%, and 9.7% respectively 3
- The Infectious Diseases Society of America reports an average of 14% mortality among hospitalized patients across various studies 2
ICU Patients
- ICU mortality is 18% compared to 5% in non-ICU hospitalized patients—nearly four times higher 1
- Severe CAP requiring ICU admission carries mortality rates of 20-50% depending on admission criteria and severity 1
Age-Related Mortality Differences
Mortality doubles with advancing age, even among hospitalized patients:
- Ages 65-69 years: 7.8% mortality 1
- Ages 75-84 years: 8.9% mortality 5
- Ages 85-90 years: 15.4% mortality 1
- Ages >90 years: 17.1% mortality 5
The incidence of CAP requiring hospitalization rises dramatically from 8.4 per 1,000 in those aged 65-69 years to 48.5 per 1,000 in those aged 90 or older 1
Impact of Comorbidities on Mortality
Specific comorbidities independently increase mortality risk:
- Chronic obstructive pulmonary disease (COPD): Odds ratio 1.77 for mortality; 39% ICU mortality if initially intubated, 50% if failing noninvasive ventilation 1, 6
- Malignancy: Odds ratio 2.25 for mortality 6
- Neurologic disease: Odds ratio 2.1 for mortality 5
- Chronic heart failure, coronary artery disease, diabetes mellitus, chronic liver disease/alcohol abuse: All independently associated with increased mortality 1
At least one comorbidity is present in 79.6% of elderly CAP patients 5
Severity-Based Mortality Using CURB-65
The CURB-65 score provides validated mortality prediction:
| CURB-65 Score | 30-Day Mortality |
|---|---|
| 0 | 0.7% |
| 1 | 2.1% |
| 2 | 9.2% |
| 3 | 14.5% |
| 4 | 40% |
| 5 | 57% |
Additional High-Risk Features
These clinical and laboratory factors independently predict mortality:
- Mechanical ventilation requirement: Odds ratio 2.99-4.2; most predominant driver of mortality (adjusted OR 3.54) 7, 5, 6
- Severe sepsis/septic shock: Approximately 50% of Spanish ICU CAP admissions involve septic shock 1
- Bacteremia: Odds ratio 1.7 for mortality 5
- Multidrug-resistant pathogens (S. aureus, P. aeruginosa, Enterobacteriaceae): Odds ratio 2.4 for mortality 5
- Pneumonia Severity Index IV or V: Odds ratio 3.2 for mortality 5
- PaO2/FiO2 ratio ≤250 mmHg: Odds ratio 3.15 for mortality 6
- Hypoalbuminemia: Odds ratio 0.27 (protective effect of higher albumin) 6
Critical Pitfalls
Delayed recognition and treatment significantly worsens outcomes:
- Patients directly admitted to ICU from emergency department have 11.7% 28-day mortality versus 23.4% for those with delayed ICU admission 7
- Mechanical ventilation within 72 hours of CAP onset: 28% mortality versus 51% if delayed ≥4 days 7
- Despite advances in antimicrobial therapy, mortality has remained relatively constant since penicillin became available 1
CAP remains the primary cause of hospital death in both ICU (73%) and non-ICU (74%) pneumonia patients 1