The author of original article mentioned staying in Indian hospital for 4 nights. Do you think a US hospital will keep you 4 nights for same surgery? I seriously doubt it. You most probably will be released few hours after the surgery or at most after overnight stay. Is the quality of care becomes lower because an Indian hospital kept a patient for 4 days instead of 1 day by US hospital? What does it say about relationship between quality of surgery and all these metrics such as duration of hospital stay, pain medication dosage and duration?
I found a lot of studies which used hospital stay duration and pain medication dosage and duration while in hospital as a proxy to quality of surgery but none that showed these metrics have anything to do with quality of surgery. Also, while quality of surgery takes into consideration the pain medication dosage and duration in the hospital, it ignores the pain medication dosage and duration patient was prescribed after being released from hospital. Similarly the overall healing and recovery time required by patient after the surgery is ignored in favor of the portion of recovery time patient spent in hospital. Hopefully, you see the incentive misalignment and mis-measurements.
You will get what you measure, nothing more nothing less. It is up to you to decide whether a measurement is relevant or not to what you trying to measure. You should not only worry about what a statistical study show but also what the study doesn't show.