The prospective cohort study included almost 52,000 patients. The full text of the paper can be viewed here. I won’t bore you with the details of how it was done except to say it looks scientifically legitimate.
The study’s authors say, “Patients typically bring expectations to medical encounters, often making specific requests of physicians, and satisfaction correlates with the extent to which physicians fulfill patient expectations. Patient requests have also been shown to have a powerful influence on physician prescribing behavior, and our findings suggest that patient satisfaction may be particularly strongly linked with prescription drug expenditures.”
Translation. What they mean is that doctors who do what their patients want receive higher satisfaction scores. This may also include admitting patients sooner rather than later, which could account for the fact that patients who were more satisfied had lower rates of emergency department visits.
So it seems patient satisfaction may not be the great “quality metric” that it is touted to be. The study concludes, “an overemphasis on patient satisfaction could have unintended adverse effects on health care utilization, expenditures, and outcomes.”
Due to something called "copyright law," I will resist the urge to quote the whole paper. I suggest you read it and judge for yourself.