Validation of the 3-day rule for stool bacterial tests in Japan.

OBJECTIVE: Stool cultures are expensive and time consuming, and the positive rate of enteric pathogens in cases of nosocomial diarrhea is low. The 3-day rule, whereby clinicians order a Clostridium difficile (CD) toxin test rather than a stool culture for inpatients developing diarrhea >3 days after admission, has been well studied in Western countries. The present study sought to validate the 3-day rule in an acute care hospital setting in Japan. METHODS: Stool bacterial and CD toxin test results for adult patients hospitalized in an acute care hospital in 2008 were retrospectively analyzed. Specimens collected after an initial positive test were excluded. The positive rate and cost-effectiveness of the tests were compared among three patient groups. PATIENTS: The adult patients were divided into three groups for comparison: outpatients, patients hospitalized for ≤3 days and patients hospitalized for ≥4 days. RESULTS: Over the 12-month period, 1,597 stool cultures were obtained from 992 patients, and 880 CD toxin tests were performed in 529 patients. In the outpatient, inpatient ≤3 days and inpatient ≥4 days groups, the rate of positive stool cultures was 14.2%, 3.6% and 1.3% and that of positive CD toxin tests was 1.9%, 7.1% and 8.5%, respectively. The medical costs required to obtain one positive result were 9,181, 36,075 and 103,600 JPY and 43,200, 11,333 and 9,410 JPY, respectively. CONCLUSION: The 3-day rule was validated for the first time in a setting other than a Western country. Our results revealed that the "3-day rule" is also useful and cost-effective in Japan.

Assessment of antigenemia assay for the diagnosis of cytomegalovirus gastrointestinal diseases in HIV-infected patients.

We conducted a single-center prospective study to evaluate the utility of cytomegalovirus (CMV) antigenemia assay for the diagnosis of CMV-gastrointestinal disease (GID). The study subjects were HIV-infected patients with CD4 count ≤200 µL/cells who had undergone endoscopy. A definite diagnosis of CMV-GID was made by histological examination of endoscopic biopsied specimen. CMV antigenemia assay (C10/C11 monoclonal antibodies), CD4 count, HIV viral load, history of HAART, and gastrointestinal symptoms as measured by 7-point Likert scale, were assessed on the same day of endoscopy. One hundred cases were selected for analysis, which were derived from 110 cases assessed as at high-risk for CMV-GID after endoscopy screening of 423 patients. Twelve patients were diagnosed with CMV-GID. Among the gastrointestinal symptoms, mean bloody stool score was significantly higher in patients with CMV-GID than in those without (2.5 vs. 1.7, p=0.02). The area under the receiver-operating characteristic curve of antigenemia was 0.80 (95%CI 0.64-0.96). The sensitivity, specificity, positive likelihood ratio (LR), and negative LR of antigenemia were 75.0%, 79.5%, 3.7, and 0.31, respectively, when the cutoff value for antigenemia was ≥1 positive cell per 300,000 granulocytes, and 50%, 92.0%, 5.5, and 0.55, respectively, for ≥5 positive cells per 300,000 granulocytes. In conclusion, CMV antigenemia seems a useful diagnostic test for CMV-GID in patients with HIV infection. The use of ≥5 positive cells per 300,000 granulocytes as a cutoff value was associated with high specificity and high positive LR. Thus, a positive antigenemia assay with positive endoscopic findings should allow the diagnosis of CMV-GID without biopsy.

[The usefulness and limitations of the new Japanese criteria for severity assessment in acute pancreatitis].

New Japanese criteria for severity assessment in acute pancreatitis were introduced in October 2008. The new criteria are simpler than the previous ones, and are also expected to be more useful for the severity assessment. We retrospectively analyzed the clinical factors in our patients to predict prognosis, and evaluated the usefulness and limitations of the new criteria. There were few missing data in the new criteria compared with the previous criteria. The areas under the receiver operating characteristic (ROC) curves for mortality prediction were 0.870 for the new criteria and 0.884 for the previous criteria. However, there were more patients whose disease severity on admission were underestimated using the new criteria and who finally progressed to worse stages including death. This evidence strongly suggests the lower sensitivity of the new criteria in mortality prediction. Repeated assessment of severity after admission will be indispensable in the proper treatment of patients with acute pancreatitis.