Role of zinc supplementation in the management of chronic liver diseases: A systematic review and meta-analysis.

INTRODUCTION AND OBJECTIVES: Zinc deficiency has been associated with poor prognosis in chronic liver disease. This systematic review and meta-analysis aimed to evaluate the role of zinc supplementation in the management of chronic liver diseases. MATERIALS AND METHODS: We searched MEDLINE, LILACS, EMBASE, and Cochrane CENTRAL databases from inception to August 2018. We included randomized controlled trials evaluating adult patients with chronic liver disease of any etiology receiving zinc supplementation. Studies with other designs or evaluating chronic conditions other than liver disease were excluded. Two reviewers independently screened and extracted data from eligible studies. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias in randomized studies. RESULTS: Of 1315 studies screened, 13 were included. Six assessed chronic hepatitis C treatment, with a relative risk of 0.83 indicating no protective effect of zinc supplementation on the improvement of sustained virological response. Three evaluated response to hepatic encephalopathy treatment, with a relative risk of 0.66 indicating a favorable effect of zinc supplementation on clinical improvement of this condition. Of four studies evaluating the management of cirrhosis, two analyzed the effect of zinc supplementation on serum albumin levels, with no statistical difference between zinc and placebo groups. CONCLUSIONS: Clinical trials assessing zinc supplementation in liver diseases do not show benefits in terms of clinical improvement or disease halting. There are possible benefits of zinc supplementation on hepatic encephalopathy, however, this is based on limited evidence. This research question is still open for evaluation in larger, well-designed, clinical trials.

Assessment of resting energy expenditure in patients with cirrhosis.

BACKGROUND: Malnutrition affects 20% to 50% of patients with cirrhosis. It may be associated with serious complications and has a direct impact on prognosis. Resting energy expenditure (REE) is an important parameter to guide the optimization of therapy and recovery of nutritional status in patients with cirrhosis. However, the REE of patients with cirrhosis is still unclear, casting doubt upon the optimal nutritional management approach. AIM: To identify the best method that predicts the REE of cirrhotic patients, using indirect calorimetry (IC) as the gold standard. METHODS: An observational study was performed on 90 patients with cirrhosis. REE was assessed by IC, bioelectrical impedance analysis (BIA), and predictive formulas, which were compared using Bland-Altman plots and the Student's t-test. RESULTS: REE values measured by IC (1607.72 ± 257.4 kcal) differed significantly from those determined by all other methods (BIA: 1790.48 ± 352.1 kcal; Harris & Benedict equation: 2373.54 ± 254.9 kcal; IOM equation: 1648.95 ± 185.6 kcal; Cunningham equation: 1764.29 ± 246.2 kcal), except the Food and Agriculture Organization of the United Nations, World Health Organization, and United Nations University (FAO/WHO/UNU) (1616.07 ± 214.6 kcal) and McArdle (1611.30 ± 241.8 kcal) equations. We found no significant association when comparing IC and 24-h dietary recall among different Child-Pugh classes of cirrhosis. CONCLUSION: The IOM and FAO/WHO/UNU equations have the best agreement with the CI. These results indicate a possibility of different tools for the clinical practice on cirrhotic patients.

The influence of age and sex on the relationship between heart rate variability, haemodynamic variables and subjective measures of acute post-operative pain.

BACKGROUND AND OBJECTIVE: Both skin conductance and surgical stress index have been proposed as useful means of assessing pain. Both methods are based on the assessment of the sympathovagal balance, which, according to reports, is influenced by age and sex, and currently neither of the assessments take these factors into account. The aim of this study was to determine the relationship between age, sex, magnitude of acute post-operative pain and haemodynamic and autonomic changes. METHODS: Two hundred twenty patients were asked to quantify their level of pain on a numeric rating scale (NRS) at different time points in the recovery room. Simultaneously, the following measures of heart rate variability were analysed: total power, low frequency, high frequency, low-to-high frequency ratio and ultra-short entropy. Additionally, SBP, heart rate and respiration rate were recorded. RESULTS: A total of 1098 NRS readings were obtained from 220 participants (123 men, 97 women, aged 40 ± 15 years). For heart rate variability, the low-to-high frequency ratio was significantly higher [mean (SE): 7.7 (0.56) vs. 6.7 (0.47); P < 0.05] and the ultra-short entropy significantly lower [mean (SE): 46.2 (0.8) vs. 47.2 (0.8); P < 0.05] for NRS 5-10 vs. NRS 0-4. Age correlated negatively with blood pressure and heart rate, and all measures of heart rate variability, except the low-to-high frequency ratio. Low-to-high frequency ratio and blood pressure were higher in men. CONCLUSION: Acute pain influences the sympathovagal balance. This response is significantly influenced by age and sex.

Skin conductance for monitoring of acute pain in adult postoperative patients: influence of electrode surface area and sampling time.

Aim of this prospective randomized study was to determine the influence of the electrode surface area and sampling time on the accuracy of the number of fluctuations in skin conductance per second to distinguish different states of acute pain. These methodological issues have been previously suggested as an explanation for contradictory data related to the accuracy of the skin conductance monitor. A total of 541 pain ratings on a numeric rating scale (0-10) were obtained from 120 adult postoperative patients. The number of fluctuations in skin conductance per second was recorded using two different electrode types (surface area 254 vs. 474 mm(2)) and sampling times (7.5 vs. 30 s). A longer sampling time did result in higher values for the number of fluctuations in skin conductance per second, though without improving its accuracy to distinguish different states of pain. However, the latter was found improved when the smaller surface area electrodes were used. A combination of small surface area electrodes and a 30 s sampling time resulted in the highest area under the curve in the receiver operating curve analysis of the method to identify states of moderate to severe pain (numeric rating scale > 3): 0.68 vs. e.g. 0.55 [data from all patients combined]). We conclude that the type of electrodes used but only to a lesser degree the sampling time influence the accuracy of the number of fluctuations in skin conductance per second to identify states of moderate or severe postoperative pain.

Resting energy expenditure in cirrhotic patients with and without hepatocellular carcinoma.

BACKGROUND: The diagnosis of malnutrition in patients with independent hepatocellular carcinoma (HCC) varies from 20% to 50%, is related to important complications and has a direct impact on the prognosis. Determination of the resting energy expenditure (REE) has become an important parameter in this population, as it allows therapeutic adjustments to recover their nutritional status. The REE in cirrhosis, with and without HCC, is not clearly defined, and requires the identification and definition of the best nutritional approach. AIM: To evaluate the REE of patients with cirrhosis, with and without HCC. METHODS: This is a prospective observational study evaluating the REE of 118 patients, 33 with cirrhosis and hepatocellular carcinoma and a control group of 85 patients with cirrhosis without HCC, using indirect calorimetry (IC), bioimpedance, and predictive formulas. RESULTS: The REE determined by IC in cirrhotic patients with HCC was 1643 ± 364 and in those without HCC was 1526 ± 277 (P = 0.064). The REE value as assessed by bioimpedance was 1529 ± 501 for those with HCC and 1660 ± 385 for those without HCC (P = 0.136). When comparing the values of REE determined by IC and predictive formulas in cirrhotics with HCC, it was observed that only the formulas of the Food and Agriculture Organization (FAO)/World Health Organization (WHO) (1985) and Cunningham (1980) presented values similar to those determined by IC. When comparing the REE values determined by IC and predictive formulas in cirrhotics without HCC, it was observed that the formulas of Schofield (1985), FAO/WHO (1985), WHO (2000), Institute of Medicine (IOM) (2005) and Katch and McArdie (1996) presented values similar to those determined by IC. CONCLUSION: The FAO/WHO formula (1985) could be used for cirrhotic patients with or without HCC; as it is the one with the values closest to those obtained by IC in these cirrhotic patients.