Table 1. Characteristics of the included studies.
| Study | Country | Design | Ethnicity | Patient characteristics | Sample size | Mean age | Male | Definitions of PPI use | Follow-up durations | Death (n) | Variables adjusted | NOS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Years | % | Months | ||||||||||
| van Vlerken 2012 | The Netherlands | PC | Caucasian | Cirrhotic patients with ascites | 84 | 55.0 | 67.0 | Any PPI use within follow-up | 28 | 17 | Age, gender, and Child-Pugh class | 7 |
| Bajaj 2012 | US | PC | Mixed | Cirrhotic patients | 207 | 55.0 | 59.9 | Current PPI use at admission | 1 | 49 | Age, gender, MELD score, albumin, serum sodium, SOFA score | 8 |
| de Vos 2013 | Belgium | RC | Caucasian | Cirrhotic patients with ascites | 51 | 57.5 | 68.6 | Current use for at least 2 weeks by medical record review | 12 | 40 | Age, gender, INR, MELD score, and Child-Pugh class | 7 |
| Min 2014 | Korea | RC | Asian | Cirrhotic patients with SBP | 134 | 58 | 73.9 | Any PPI use during hospitalization | Within hospitalization | 41 | Age, gender, serum sodium, MELD score, and Child-Pugh class | 8 |
| Kwon 2014 | Korea | RC | Asian | Cirrhotic patients with ascites | 533 | 62.3 | 75.4 | Current use of PPI within 30 days before admission | 1 | 175 | Age, gender, and MELD score | 8 |
| Mandorfer 2014 | Austria | RC | Caucasian | Cirrhotic patients with ascites | 607 | 57.5 | 70.0 | Current use on admission by medical record review | 10 | 358 | Age, gender, and MELD score | 8 |
| Dultz 2015 | Germany | PC | Caucasian | Cirrhotic patients | 272 | 57.0 | 66.9 | Current PPI use at admission | 9 | 86 | Age, gender, etiology of cirrhosis, and MELD Score | 8 |
| Merli 2015 | Italy | PC | Caucasian | Cirrhotic patients | 400 | 61.5 | 70.3 | Any PPI use during hospitalization | Within hospitalization | 39 | Age, gender, and MELD score | 7 |
| Cole 2016 | U.K. | RC | Caucasian | Cirrhotic patients | 198 | 56.0 | 65.2 | Current PPI use at discharge | 23 | 38 | Age, gender, and MELD score | 7 |
| Kim 2017 | Korea | RC | Asian | Cirrhotic patients with a previous SBP | 307 | 57.6 | 77.1 | Any PPI use for at least 1 week during follow-up | Within hospitalization | 91 | Age, gender, etiology of liver disease, serum sodium, SCr, and Child-Pugh class | 7 |
| Miozzo 2017 | Brazil | RC | Caucasian | Cirrhotic patients | 258 | 53.6 | 58.2 | Any PPI use during follow-up | 30 | 155 | Age, gender, and MELD score | 7 |
| Hung 2018a | China | RC | Asian | Cirrhotic patients with SBP | 2574 | 60.9 | 71.8 | Current PPI use during hospitalization | 12 | 1785 | Age, gender, and MELD score | 7 |
| Hung 2018b | China | RC | Asian | Cirrhotic patients with HE | 5020 | 62.5 | 68.0 | Current PPI use during hospitalization | 12 | 3210 | Age, gender, etiology of cirrhosis, and MELD score | 7 |
| Smith 2018 | US | RC | Mixed | Cirrhotic patients with CDI | 400 | 58.5 | 60.0 | Current PPI use at admission | 30 | 44 | Age, gender, serum albumin, and MELD score | 7 |
| Tergast 2018 | Germany | RC | Caucasian | Cirrhotic patients with ascites | 613 | 56.1 | 62.0 | Current PPI use within 7 days before admission | 1 | 121 | Age, gender, and MELD score | 8 |
| Janka 2019 | Hungary | RC | Caucasian | Cirrhotic patients | 350 | 56.0 | 53.7 | Regular use of PPI for at least 80% of follow-up periods based on medical chart review | 60 | 147 | Age, gender, and MELD score | 7 |
| Nardelli 2019 | Italy | PC | Caucasian | Cirrhotic patients | 310 | 62.2 | 71.3 | Current PPI use at least 4 weeks before admission | 14 | 112 | Age, gender, serum albumin, serum sodium, and MELD score | 9 |
| Lewis 2019 | US | RC | Caucasian | Cirrhotic patients after TIPS | 2284 | 56.4 | 66. 1 | Any PPI use at follow-up | 13 | 115 | Age, gender, and MELD score | 8 |
| Dam 2019 | Denmark | RC | Caucasian | Cirrhotic patients | 1198 | 57.5 | 70.0 | Current PPI use at admission | 3 | 81 | Age, gender, MELD score, history of variceal bleeding, and history of HE | 7 |
| Hung 2019 | China | RC | Asian | Cirrhotic patients with pneumonia | 4804 | 63.0 | 71.2 | Current PPI use during hospitalization | 3 | 638 | Age, gender, etiology of cirrhosis, and MELD score | 7 |
| De Roza 2019 | Singapore | RC | Asian | Cirrhotic patients | 295 | 62.8 | 68.1 | Any PPI use at follow-up | 6 | 115 | Age, gender, etiology of cirrhosis, history of variceal bleeding and HE, and MELD score | 8 |
Abbreviations: CDI, Clostridium difficile Infection; DM, diabetes mellitus; HE, hepatic encephalopathy; INR, international normalized ratio; MELD, Model for End-stage liver Disease; NOS, the Newcastle–Ottawa Score; PC, prospective cohort; PPI, proton pump inhibitor; RC, retrospective cohort; SCr, serum creatinine; SBP, spontaneous bacterial peritonitis; TIPS, transjugular intrahepatic portosystemic shunt.