Predictive Value of Blood Ammonia in the Prognosis of Acute Liver Failure Evaluated by Receiver Operating Characteristic Curves.

BACKGROUND: To investigate the predictive value of blood ammonia (BLA) quantification in the prognosis of acute liver failure (ALF). METHODS: Seventy-one patients with ALF were enrolled and BLA concentration was measured in all patients. After following up for 28 days, patients were divided into two groups: the surviving group (n = 21) and the deceased group (n = 50). An independent-samples t-test was used to compare BLA concentrations between the two groups, and receiver operating characteristic curves were used to ¬evaluate the predictive value of BLA in the prognosis of ALF. A fourfold table analysis was performed with the determined BLA cutoff value. RESULTS: The average concentration of BLA in the deceased group was significantly higher compared with the surviving group (144.50 µmol/L vs. 106 µmol/L, respectively; P = .035). The cutoff BLA concentration for a good ALF prognosis was 122.5 µmol/L. The area under the curve was 0.659. Both the sensitivity and specificity were >0.6. The 95% CIs for sensitivity and specificity were 0.452-0.733 and 0.477-0.878, respectively. The fourfold table analysis revealed a positive predictive value of 83.3%, a negative predictive value of 42.9%, a misdiagnosis rate of 28.6%, and an accuracy of 63.4%. CONCLUSION: With a cutoff BLA concentration of 122.5 µmol/L, the prognosis of ALF could be predicted with high sensitivity and specificity, a positive predictive value, a low misdiagnosis rate, and good accuracy.

Prevalence and associated knowledge of hepatitis B infection among healthcare workers in Freetown, Sierra Leone.

BACKGROUND: Hepatitis B virus (HBV) is considered highly prevalent in West Africa. However, major gaps in surveillance exist in Sierra Leone. Although healthcare workers (HCWs) are at high risk for HBV infection, little is known about the prevalence and knowledge of hepatitis B among HCWs in Sierra Leone. METHODS: A cross-sectional study of all HCWs at the No. 34 Military Hospital located in Freetown, Sierra Leone, was conducted from March 20 to April 10, 2017. Whole blood was collected and screened for HBV markers using a one-step rapid immunochromatographic test with positive samples tested for HBV DNA. Additionally, questionnaires assessing self-reported knowledge of HBV infections were administered to all participants. Data were processed and analyzed using SPSS (version 17.0) software. RESULTS: A total of 211 HCWs were included in this study with a median age of 39.0 years (range: 18-59). Of the participating HCWs, 172 (81.5%) participants were susceptible (all markers negative), 21(10.0%) were current HBV (HBsAg positive) and nine (4.3%) were considered immune because of past infection (HBsAg negative and anti-HBc positive; anti-HBs positive). Additionally, nine (4.3%) participants displayed immunity to the virus as a result of prior hepatitis B vaccination (only anti-HBs positive). Of the 21 HCWs with positive HBsAg, 13 (61.9%) had detectable HBV DNA. There was a significantly lower risk for current HBV infection among HCWs older than 39 years (OR 0.337, p = 0.046). In addition, only 14 (6.6%), 73 (34.6%) and 82 (38.9%) participants in this survey had adequate knowledge about the clinical outcome, routes of transmission, and correct preventive measures of HBV infection, respectively. CONCLUSIONS: HCWs in Sierra Leone lacked adequate knowledge of the hepatitis B virus. Additionally, the low coverage rate of hepatitis B vaccination among HCWs fails to meet WHO recommendations, leaving many of the sampled HCWs susceptible to infection. This study reaffirms the need for more intensive training for HCWs in addition to strengthening vaccination programmes to protect HCWs against HBV in Sierra Leone.