Inclusion criteria
Systematic reviews (with or without meta-analysis) or primary studies were included that met the following criteria: (Cochrane ‘PICOS’ format):
P - adults aged 18 years or older
I - PPI therapy for any indication for duration of more than 12 weeks
C – Non-use or histamine type-2 receptor antagonist (H2RA) use
O – All-cause mortality
Primary studies were sought and included that had not been available by SR search cut-off dates up to January 2020.