There is definitely a correlation between the two, despite what some fans who dislike the midichlorian concept say (I can sympathize). See Star Wars: Revenge of the Sith by Stover, a book which is G-level canon.
Here is the appropriate quote (p. 417, hardback, first edition):
And you rage and scream and reach through the Force to crush the
shadow who has destroyed you, but you are so far less now than what
you were, you are more than half machine, you are like a painter gone
blind, a composer gone deaf, you can remember where the power was but
the power you can touch is only a memory, and so with all your
world-destroying fury it is only droids around you that implode, and
equipment, and the table on which you were strapped shatters, and in
the end, you cannot touch the shadow.
A bit of context with this quote: this book will, from time to time, have sections describing how the characters are feeling, what they are doing, etc. These sections are written in second person, directly addressing the reader as if you were the character in question. This is one of my favorite parts of the book, which is why I remembered it offhand.
So, this quote is describing Anakin Skywalker/Darth Vader. "The shadow" refers to Palpatine, who is responsible in Anakin's eyes for the death of Padmé. As you can see, the quote makes it pretty clear that Darth Vader is a lot weaker than he once was.
In Empire of Dreams, Lucas says this:
However, after all of his limbs were severed, and he was extremely
burned on Mustafar, he lost much of his Force potential. As Darth
Vader, Skywalker was believed to have had roughly 80% of the strength
of the Emperor. Had he sustained none of his injuries on Mustafar, he
would have been twice as powerful.
If that quote is not convincing enough, I don't know what is.
As I said above, there are some purists who believe the midichlorians spoiled the magic/mystic element of Star Wars and so therefore simply discount them. But if you want a canonical answer, it's pretty clear: losing body parts does diminish Force ability.