Letters to the Editor
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resection for hepatocellular carcinoma. Herein, we would like to raise the following comments: In this study, patients were divided into two groups according to the presence or absence of postoperative complications. Between them, significant differences existed in some aspects of baseline and intraoperative characteristics, including American Society of Anesthesiologists score, Charlson Index, Model for End-Stage Liver Disease score, serum bilirubin and aspartate aminotransferase level, and intraoperative blood loss, suggesting an unbalanced enrollment because of these confounding variables between these two groups. As a matter of fact, propensity score matching analysis has been generally used in observational studies, which enables better balance between groups across all putative risk factors and evaluates the extent of balanced match in a measurable approach [2,3]. Therefore, it is suggested that this advanced statistical method be used here. In addition, as we think, the number of variables on baseline and intraoperative characteristics investigated in this study was far from enough. For example, comorbid illnesses (including hypertension, diabetes mellitus, renal dysfunction, etc.), preoperative hemoglobin level, the presence of perioperative blood transfusion, and the presence of concomitant surgical procedures (including cholecystotomy, splenectomy, and hilar lymph node dissection) were not provided, which actually are very likely to influence either the presence of postoperative complications or long-term survival after operation. In conclusion, clarification regarding the above-mentioned omissions would greatly solidify the conclusions of the study by Khandoga et al. [1]. Acknowledgements
This work was supported in part by National Natural Science Foundation of China (nos 81472284 and 81672699) and Shanghai Pujiang Program (no. 16PJD004).
1315
Helicobacter pylori among patients with cirrhosis: incidence or prevalence? Rinaldo Pellicano, Department of Gastroenterology and Hepatology, Molinette Hospital, Turin, Italy Correspondence to Rinaldo Pellicano, MD, Department of Gastroenterology and Hepatology, Molinette Hospital, Via Cavour 31, Torino 10126, Italy Tel: + 39 11 6333565; fax: + 39 11 6336249; e-mail: [email protected] Received 9 August 2017 Accepted 10 August 2017
In a recently published article, Pogorzelska et al. [1] investigated the association between Helicobacter pylori infection and cirrhosis due to diverse causes. H. pylori infection was detected by means of serology. They found a significantly higher rate of H. pylori-seropositivity among patients with postinflammatory cirrhosis as compared with those suffering from alcoholic liver disease. In the Aim section, the authors reported that they searched for the incidence of H. pylori infection. The same affirmation was done in the Results section when they reported ‘The incidence of H. pylori infection…’ [1]. To express morbidity, two types of rates are available: incidence and prevalence rates. The former is a direct estimate of the probability of developing a disease during a specified period of time. The latter refers to the number of cases of disease present in the population at a specified time [2]. As it is known that H. pylori infection is acquired in the preschool age, with the associated effects of family size, low socioeconomic status and education, and that the risk declines rapidly after 5 years of age [3], I think that the study by Pogorzelska et al. [1] does not evaluate the incidence but the prevalence. Acknowledgements
Conflicts of interest
Conflicts of interest
There are no conflicts of interest.
There are no conflicts of interest.
References 1
2 3
Khandoga A, Drefs M, Schoenberg M, Schiergens T, Frenes K, Op den Winkel M, et al. Differential significance of early surgical complications for acute and long-term recurrence-free survival following surgical resection of hepatocellular carcinoma: do comorbidities play a role? Eur J Gastroenterol Hepatol 2017; 29:1045–1053. Adamina M, Guller U, Weber WP, Oertli D. Propensity scores and the surgeon. Br J Surg 2006; 93:389–394. Hemmila MR, Birkmeyer NJ, Arbabi S, Osborne NH, Wahl WL, Dimick JB. Introduction to propensity scores: a case study on the comparative effectiveness of laparoscopic vs open appendectomy. Arch Surg 2010; 145:939–945.
DOI: 10.1097/MEG.0000000000000966
References 1
2
3
Pogorzelska J, Lapinska M, Kalinowska A, Lapinski TW, Flisiak R. Helicobacter pylori infection among patients with liver cirrhosis. Eur J Gastroenterol Hepatol 2017; 29:1161–1165. Lilienfeld AM, Lilienfeld DE. The derivation of biological inferences from epidemiological studies. In: Lilienfeld AM, Lilienfeld DE, editors. Foundations of epidemiology. New York, NY: Oxford University Press; 1980. pp. 289–321. Pellicano R, Ribaldone DG, Fagoonee S, Astegiano M, Saracco G, Mégraud F. A 2016 panorama of Helicobacter pylori infection: key messages for clinicians. Panminerva Med 2016; 58:304–317.
DOI: 10.1097/MEG.0000000000000978
Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.
www.eurojgh.com
resection for hepatocellular carcinoma. Herein, we would like to raise the following comments: In this study, patients were divided into two groups according to the presence or absence of postoperative complications. Between them, significant differences existed in some aspects of baseline and intraoperative characteristics, including American Society of Anesthesiologists score, Charlson Index, Model for End-Stage Liver Disease score, serum bilirubin and aspartate aminotransferase level, and intraoperative blood loss, suggesting an unbalanced enrollment because of these confounding variables between these two groups. As a matter of fact, propensity score matching analysis has been generally used in observational studies, which enables better balance between groups across all putative risk factors and evaluates the extent of balanced match in a measurable approach [2,3]. Therefore, it is suggested that this advanced statistical method be used here. In addition, as we think, the number of variables on baseline and intraoperative characteristics investigated in this study was far from enough. For example, comorbid illnesses (including hypertension, diabetes mellitus, renal dysfunction, etc.), preoperative hemoglobin level, the presence of perioperative blood transfusion, and the presence of concomitant surgical procedures (including cholecystotomy, splenectomy, and hilar lymph node dissection) were not provided, which actually are very likely to influence either the presence of postoperative complications or long-term survival after operation. In conclusion, clarification regarding the above-mentioned omissions would greatly solidify the conclusions of the study by Khandoga et al. [1]. Acknowledgements
This work was supported in part by National Natural Science Foundation of China (nos 81472284 and 81672699) and Shanghai Pujiang Program (no. 16PJD004).
1315
Helicobacter pylori among patients with cirrhosis: incidence or prevalence? Rinaldo Pellicano, Department of Gastroenterology and Hepatology, Molinette Hospital, Turin, Italy Correspondence to Rinaldo Pellicano, MD, Department of Gastroenterology and Hepatology, Molinette Hospital, Via Cavour 31, Torino 10126, Italy Tel: + 39 11 6333565; fax: + 39 11 6336249; e-mail: [email protected] Received 9 August 2017 Accepted 10 August 2017
In a recently published article, Pogorzelska et al. [1] investigated the association between Helicobacter pylori infection and cirrhosis due to diverse causes. H. pylori infection was detected by means of serology. They found a significantly higher rate of H. pylori-seropositivity among patients with postinflammatory cirrhosis as compared with those suffering from alcoholic liver disease. In the Aim section, the authors reported that they searched for the incidence of H. pylori infection. The same affirmation was done in the Results section when they reported ‘The incidence of H. pylori infection…’ [1]. To express morbidity, two types of rates are available: incidence and prevalence rates. The former is a direct estimate of the probability of developing a disease during a specified period of time. The latter refers to the number of cases of disease present in the population at a specified time [2]. As it is known that H. pylori infection is acquired in the preschool age, with the associated effects of family size, low socioeconomic status and education, and that the risk declines rapidly after 5 years of age [3], I think that the study by Pogorzelska et al. [1] does not evaluate the incidence but the prevalence. Acknowledgements
Conflicts of interest
Conflicts of interest
There are no conflicts of interest.
There are no conflicts of interest.
References 1
2 3
Khandoga A, Drefs M, Schoenberg M, Schiergens T, Frenes K, Op den Winkel M, et al. Differential significance of early surgical complications for acute and long-term recurrence-free survival following surgical resection of hepatocellular carcinoma: do comorbidities play a role? Eur J Gastroenterol Hepatol 2017; 29:1045–1053. Adamina M, Guller U, Weber WP, Oertli D. Propensity scores and the surgeon. Br J Surg 2006; 93:389–394. Hemmila MR, Birkmeyer NJ, Arbabi S, Osborne NH, Wahl WL, Dimick JB. Introduction to propensity scores: a case study on the comparative effectiveness of laparoscopic vs open appendectomy. Arch Surg 2010; 145:939–945.
DOI: 10.1097/MEG.0000000000000966
References 1
2
3
Pogorzelska J, Lapinska M, Kalinowska A, Lapinski TW, Flisiak R. Helicobacter pylori infection among patients with liver cirrhosis. Eur J Gastroenterol Hepatol 2017; 29:1161–1165. Lilienfeld AM, Lilienfeld DE. The derivation of biological inferences from epidemiological studies. In: Lilienfeld AM, Lilienfeld DE, editors. Foundations of epidemiology. New York, NY: Oxford University Press; 1980. pp. 289–321. Pellicano R, Ribaldone DG, Fagoonee S, Astegiano M, Saracco G, Mégraud F. A 2016 panorama of Helicobacter pylori infection: key messages for clinicians. Panminerva Med 2016; 58:304–317.
DOI: 10.1097/MEG.0000000000000978
Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.
