According to WSJ:"More than 200 nursing schools have established or plan to launch doctorate of nursing practice programs to equip graduates with skills the schools say are equivalent to primary-care physicians.
Nurses with doctorates use DrNP after their name, and can also use the designation Dr. as a title.
A 2000 study published in JAMA showed comparable patient outcomes in patients randomly assigned to nurse practitioners and primary-care physicians" (emphasis is mine).
The outcomes would depend on the environment, one would suspect. Judging from my experience with some excellent mid-level providers, it may be challenging for a DrNP to achieve similar outcomes to an MD in the complex environment of a large tertiary care center.
References:
Making Room For 'Dr. Nurse' WSJ.
My take: Dr. Nurses, supporting universal care: comments. KevinMD.
Image source: OpenClipArt.org, public domain.