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 DATA IDENTIFICATION Computerized bibliographic search of published and unpublished research.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.