Is the positive correlation for chronic kidney disease with use of proton-pump inhibitors a causal relationship, or due to some other factor in common?

This is a causal relationship, meaning that the proton-pump inhibitors, in and of themselves, have a deleterious long-term effect on the kidney. And that is a major concern considering that once damaged, the ability to heal will be uncertain. And given there can be quite easily, additional risk factors for individuals on this kind of medication, such as having a chronic viral infection causing diabetes, this is something physicians need to keep a close eye on and ideally, minimize utilization to protect their patients.