What is the likelihood of death in an elderly patient with Clostridioides difficile (C. diff) infection?

Mortality Risk in Elderly Patients with C. difficile Infection

Elderly patients with C. difficile infection face a 13% risk of death within 30 days and 37% mortality at one year, with CDI directly causing a 2.5-fold increased risk of 30-day mortality compared to matched controls without diarrhea. 1

Age-Specific Mortality Rates

The likelihood of death increases substantially with advancing age in CDI patients:

• Patients aged 65 years and older experience the highest incidence of CDI at 627.7 cases per 100,000 persons, with correspondingly elevated mortality 2
• Patients aged 70 years and older have significantly worse outcomes, with age >70 years serving as a strong independent predictor of progression to fulminant disease 3
• The "oldest old" (age 80+) demonstrate 8.6% mortality at 30 days and 17.1% at 90 days in dedicated studies of this age group 4
• Critically ill elderly patients (≥65 years) in ICU settings are 68% more likely to experience 30-day mortality compared to younger ICU patients with CDI 5

Direct CDI-Attributable Mortality

The attributable mortality specifically caused by CDI itself (not just associated deaths) is 10.9%, meaning that approximately 1 in 9 deaths among elderly CDI patients can be directly attributed to the infection 6. This represents the excess mortality beyond what would be expected from their baseline comorbidities alone 1.

Factors That Increase Mortality Risk

Laboratory Predictors

• Profound leukocytosis or leukopenia (WBC ≥35,000/μL or <4,000/μL) independently predicts mortality 2
• Elevated WBC count is independently associated with treatment failure, which subsequently increases mortality risk 4
• Bandemia (neutrophil bands ≥10%) serves as a mortality predictor 2

Clinical Predictors

• Cardiorespiratory failure requiring intubation or vasopressors dramatically increases mortality 2
• Acute renal failure and mental status changes indicate progression to fulminant disease 3
• Coronary artery disease as a comorbidity independently predicts 90-day mortality (P=0.02) 4
• Congestive heart failure history may increase mortality risk, particularly in patients receiving certain treatments 2

Severity-Based Mortality

• Fulminant colitis requiring emergency colectomy carries 33% overall mortality 2
• Patients requiring emergency surgery have mortality rates of 9.7% (ages 65-79) and 17.8% (age >80) 2
• Preoperative physiological status is the strongest predictor of surgical mortality, including preoperative intubation, acute renal failure, multiple organ failure, and shock requiring vasopressors 2

Timing of Death

CDI-related deaths occur predominantly within the first 30 days after diagnosis 1. This early mortality window emphasizes the critical importance of:

• Rapid recognition of severe disease markers 3
• Early surgical consultation when indicated (before vasopressor requirement or respiratory failure) 2
• Aggressive initial treatment in high-risk elderly patients 4

Comparative Mortality Context

To contextualize the mortality burden:

• CDI patients have 2.5-fold increased 30-day mortality compared to hospitalized controls without diarrhea, even after adjusting for age, sex, and underlying diseases 1
• The highest mortality occurs in endemic situations (not just outbreaks), with elderly patients and certain ribotypes (particularly 027) showing the worst outcomes 1
• Prior to 2000, CDI-attributable mortality was <2%, but has increased substantially in the modern era 2

Critical Clinical Pitfall

The absence of diarrhea does not exclude fulminant CDI and may actually signal progression to fulminant infection with ileus, a particularly ominous sign that clinicians must not miss 3. Elderly patients may present atypically, with only 50% presenting with typical lower quadrant abdominal pain, 17% with fever, and 43% without leukocytosis 2.

Long-Term Outcomes Beyond Acute Mortality

Beyond immediate death risk, elderly CDI survivors face:

• Increased risk of transfer to long-term care facilities (OR 1.74 at 30 days) 6
• Increased risk of skilled nursing facility placement (OR 2.52 at 30 days) 6
• Increased subsequent hospitalization risk extending through one year 6
• Recurrence rates of 10-30% after first episode, though paradoxically lower in elderly compared to younger patients 2

Risk Stratification for Clinical Decision-Making

The RASA score provides bedside mortality prediction for elderly ICU patients with CDI (ROC 0.740):

• R: Absence of chronic respiratory disease
• A: Age 75+ years
• S: Septic shock
• A: APACHE II score ≥20

This simple tool can guide treatment intensity decisions in critically ill elderly patients 5.

The magnitude of mortality risk varies inversely with baseline CDI probability—patients with the lowest baseline probability of CDI who develop the infection face the highest relative mortality risk (HR 3.04), suggesting that even "lower-risk" elderly patients warrant aggressive intervention 6.