I am neither an expert nor a historian and so am unable to answer your specific question. I just wanted to point you to another very lively discussion about Mother Theresa that took place on /r/askhistorians: https://www.reddit.com/r/AskHistorians/comments/1hn2eh/askhistorians_consensus_on_mother_theresa/.

It's a very interesting read, and does a good job of separating rumours from what is actually known. There are also attempts to put various issues into context beyond those raised by the post that brought you here: for example the very first line of the /r/bestof post is somewhat problematic as Mother Theresa did not operate a hospital to treat illness, but instead operated hospices... places where people often close to death are taken so that they do not have to die alone. You can see why the statistic about the number of deaths amongst patients is problematic in those circumstances.

I also found the thread I linked you to fascinating as an example of how historians try to battle their own biases in the quest to write good history. It's a sad but interesting read, and I wish you luck on snagging an actual historian to answer your question!

/Edit - Definitely not an expert on Mother Theresa, especially seeing as how I repeatedly spelt her name wrong. Corrected!