The article is published by Dove Medical Press, which offers open access journals on an "author pays" model. The NIH URL seems to be merely the National Library of Medicine medical article indexing service.
The trouble is that Dove Medical Press charges quite a high fee (around $1,500) for doing a peer review and putting your article on its web site. Its not clear what level of peer review is provided, but the author fee model obviously creates a perverse incentive to reduce standards. Hence there must be a strong suspicion that this article has not undergone a rigorous review by experts in the field.
Dove Medical Press lost its accreditation with the Open Access Group in 2013 after publishing a deliberately bogus "sting" article. They got accreditation back last year after beefing up their processes.
This article (PDF) reviews a number of such outfits. Dove Medical Press doesn't seem to be quite as bogus as some, but its not good.
Looking through the article itself there are some things that raise concern:
- The study is very small: 4 subjects and 4 controls were studied over 4 days. Some measurements are given, but information about what was measured and how is sparse to non-existent.
- Much of the article seems to be unsupported speculation about the movement of electrons through bits of stuff in the body. There is nothing here that resembles a coherent theory.
- The authors consistently confuse the role of electron donation in chemical reactions with ideas related to electrical current.
In short, I can't imagine a reputable journal publishing something like this, and I won't be earthing my bed.