By Tara Haelle

US Medicare patients with diabetes who receive their care from nurse practitioners are slightly less likely to be hospitalized for a potentially preventable condition compared with those cared for by physicians, according to a study published recently.

"These results may represent a valid finding of better outcomes from primary care delivered by nurse practitioners," write Yong-Fang Kuo, PhD, and colleagues at the University of Texas Medical Branch in Galveston. "Alternatively, they may have resulted from confounding by selection biases not completely controlled for in the analyses."

The researchers compared potentially preventable hospitalizations from 2007 to 2010 among 345,819 Medicare patients with any diagnosis of diabetes. Of these, 93,443 patients had received all their primary care from nurse practitioners (a total of 136,348 person-years), and 252,376 patients had received all their care from a generalist physician (553,890 person-years).

Nurse practitioners' patients had a 10% lower risk of hospitalization for a potentially preventable condition (odds ratio [OR], 0.90) and a 6% lower risk of hospitalization for poor diabetes control, such as hypoglycemia or hyperglycemia (OR, 0.94), compared with patients of physicians. Similarly, the odds for hospitalization for other conditions was slightly lower among nurse practitioners' patients than among physicians' patients (OR, 0.96).

All-cause mortality between the groups was not statistically different over 4 years, however. In the nurse-practitioner group, 17.15% of patients died, compared with 16.97% of physicians' patients (adjusted hazard ratio, 1.00; 95% CI, 0.97–1.03).

"We find it surprising that the findings of lower rate of potentially avoidable hospitalization among nurse practitioners patients still hold true, despite use of multiple advanced analyses to adjust for complexity and severity of illnesses between diabetes patients cared for by nurse practitioners vs MDs," said coauthor Mukaila A Raji, MD.

More Patients Receiving Care From Nurse Practitioners

As background, the researchers explain that primary care provided by nurse practitioners has been promoted as a means of addressing the shortage of primary-care physicians. There was a 15-fold increase in the number of patients receiving care from nurse practitioners from 1998 to 2010, and 22 US states have changed their policies to allow nurse practitioners to practice and prescribe without physician supervision.

However, some medical groups have raised concerns about primary care delivered solely by nurse practitioners, arguing that outcomes might not be comparable, particularly in complex patients. A number of trials in controlled settings have found comparable outcomes between the two groups, but there have been no population-based studies of outcomes of primary care delivered by nurse practitioners and MDs.

The current results show that patients of nurse practitioners were more likely to live in rural areas and be younger, female, and white and have lower income, possibly because individuals with these demographics may be more open to receiving care from nurse practitioners, Dr Raji suggested.

And yet the findings reveal that nurse practitioners provide the same quality of clinical care as MDs, he added.

"Nurse practitioners will continue to play a key role in improving access to primary care for seniors living with diabetes, especially those living in rural and nonmetropolitan areas," said Dr Raji.

"I anticipate nurse practitioners playing similar roles in addressing the primary-care gap for patients with other ambulatory sensitive conditions, such as congestive heart failure, chronic obstructive pulmonary disease, and asthma."

Because the researchers limited their study population to elderly patients with fee-for-service Medicare coverage, the findings cannot be generalized to the general US population or to other countries, Dr Raji stressed.

Yet the results fit with the goal of the Affordable Care Act to improve patient-care access while delivering high-value patient-centered care, he added.

"Reducing unnecessary hospital admissions and readmissions is a key benchmark of quality and the basis for financial reimbursement for the healthcare system."

"Our finding of the association of nurse practitioners' diabetes primary care with lower risk of avoidable hospitalizations likely reflects the unique skills of nurse practitioners in care coordination, transitional care management, advance care planning, and preventive care," he concluded.