Nosocomial pneumonia and the role of gastric pH. A meta-analysis.

PURPOSE: To examine the differential effect of drugs used for stress ulcer prophylaxis on nosocomial pneumonia in critically ill patients. DATA IDENTIFICATION: Computerized bibliographic search of published and unpublished research. STUDY SELECTION: Independent review of 48 randomized controlled trials of prophylaxis identified eight relevant studies. DATA ABSTRACTION: The population, intervention, and outcomes were evaluated by duplicate independent review. RESULTS: The incidence of pneumonia was lower in critically ill patients receiving antacids and/or histamine-2-receptor antagonists as compared with patients receiving no stress ulcer prophylaxis (common odds ratio 0.42, 95 percent CI 0.17 to 1.11). When stress ulcer prophylactic therapy was titrated to achieve a gastric pH of 3.5 or greater, there was a trend favoring a decreased incidence of pneumonia (0.66, 95 percent CI 0.24 to 1.78). In trials comparing sucralfate with pH-altering drugs, the common odds ratio of 0.55 (0.28 to 1.06) suggests a 45 percent risk reduction with the use of sucralfate. CONCLUSION: Stress ulcer prophylaxis with drugs which raise gastric pH does not increase the incidence of pneumonia in comparison to placebo or control therapy. The use of sucralfate is associated with a lower incidence of nosocomial pneumonia in comparison to agents which raise gastric pH. However, methodologic deficiencies, small sample sizes, and the failure to examine the effects of antacids and histamine-2-receptor antagonists separately make a large prospective randomized trial necessary to confirm or refute these findings.