JAMA: PCPs with ambulatory training may boost outcomes

There is a widely held expectation that higher numbers of clinicians will lead to patients receiving more effective primary care. However, a May 25 study in the Journal of the American Medical Association shows that the key to better outcomes might be more primary care physicians trained in ambulatory care.

To measure the association between the PCP workforce and patient outcomes, Chiang-Hua Chang, PhD, of the Center for Health Policy Research at the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, N.H., and colleagues conducted a cross-sectional analysis of the outcomes of a sample of fee-for-service Medicare beneficiaries age 65 years or older, comparing outcomes by the number of adult PCPs (general internists and family physicians) across Primary Care Service Areas (PCSAs).

The researchers used a sample of 20 percent of the national fee-for-service Medicare beneficiaries and analyzed 100 percent of their physician and hospital claims. Beneficiaries were included if they resided in the U.S., were age 65 to 99 on Jan. 1, 2007, and had Part A (acute care in facilities, including hospitals) and Part B (clinician services) coverage in 2007. Chang and colleagues assigned a PCSA to each study beneficiary based on his or her resident zip code.

In areas with the highest quintile of PCPs, patients had fewer ambulatory care sensitive condition (ACSC) hospitalizations, Chang and colleagues wrote. ACSC hospitalizations are regarded as largely preventable admissions when adequate and timely ambulatory care is provided, according to the study.

Study beneficiaries’ hospitalization claims for any of 12 ACSC conditions (convulsions, chronic obstructive pulmonary disease, pneumonia, asthma, congestive heart failure, hypertension, angina, cellulitis, diabetes, gastroenteritis, kidney infection, urinary infection and dehydration) occurring in acute care hospitals were identified from the 2007 Medicare Provider Analysis and Review. Deaths of study beneficiaries occurring in 2007 were identified in the Medicare Denominator file, the researchers stated.

They measured Medicare program payments by linking study beneficiaries to a 5 percent sample (i.e., 5 percent of all fee-for-service Medicare beneficiaries, or a one-fourth subset of the study population) reported in the 2007 Continuous Medicare History Sample file. Medicare program spending was classified either as dollars spent on acute care facilities (Part A spending for acute facilities, such as inpatient and skilled nursing) or physician and other clinician payments (Part B spending for clinicians).

Beneficiaries residing in areas with the highest quintile of PCP full-time equivalents (FTEs) had lower mortality (5.19 vs. 5.49 per 100 beneficiaries), fewer ACSC hospitalizations (72.53 vs. 79.48 per 1,000 beneficiaries) and higher overall Medicare spending ($8,857 vs. $8,769 per beneficiary) than did beneficiaries in areas in the lowest quintile, according to the researchers.

“A higher level of primary care physician workforce, particularly with an FTE measure that may more accurately reflect ambulatory primary care, was generally associated with favorable patient outcomes,” wrote Chang and colleagues.

The adult PCP workforce varied widely across the 6,542 PCSAs, with an approximate five-fold variation in PCPs per population across PCSA quintiles (median of 17.4 PCPs per 100,000 population in the lowest quintile PCSAs vs. 81.3 per 100,000 population in the highest quintile PCSAs), the researchers found.

“Similarly, an almost two-fold difference in primary care FTEs per 100,000 beneficiaries was observed between the lowest and highest quintiles (median of 64.7 per 100,000 beneficiaries in the lowest quintile PCSAs vs. 103.2 per 100,000 beneficiaries in the highest quintile PCSAs).”

A larger local workforce of PCPs has a generally positive benefit for Medicare populations, but this association may not simply be the result of having more physicians trained in primary care in an area, the study stated. “Instead, associations were much stronger with a measure of primary care activity that was linked to a central concept of primary care—ambulatory care delivered in an office or clinic setting by physicians trained in primary care.”

The associations of PCP workforce on spending were mixed, the authors stated. “One possible explanation is that some hallmarks of primary care, such as early detection, prevention and coordination of care, might reduce hospital use but result in a tradeoff of greater clinician spending.”

The authors cited several limitations in the study. For example, the PCP workforce did not include data about advanced practice nurses and physician assistants. In addition, the cross-sectional analysis did not capture longitudinal care for an extended period—one of the core attributes of primary care, the authors stated.

“The benefits of a primary care workforce appear quite sensitive to the accurate discrimination of those physicians trained in primary care with those practicing ambulatory primary care," wrote Chang and colleagues. "Recognizing this difference is important not just to improve primary care clinician measurement, but also as an indication of the drift of physicians trained as primary care physicians to nonprimary care careers.”

“Increasing the training capacity of family medicine and internal medicine may have disappointing patient benefits if the resulting physicians are primary care in name only,” the authors wrote.

The Robert Wood Johnson Foundation and the National Institute on Aging partly supported the study.