title: Primary care and behavioral health practice size: the challenge for health care reform.
abstract: BACKGROUND
  We investigated the size profile of US primary care and behavioral health physician practices since size may impact the ability to institute care management processes (CMPs) that can enhance care quality.
  
  
  METHODS
  We utilized 2009 claims data from a nationwide commercial insurer to estimate practice size by linking providers by tax identification number. We determined the proportion of primary care physicians, psychiatrists, and behavioral health providers practicing in venues of >20 providers per practice (the lower bound for current CMP practice surveys).
  
  
  RESULTS
  Among primary care physicians (n=350,350), only 2.1% of practices consisted of >20 providers. Among behavioral health practitioners (n=146,992) and psychiatrists (n=44,449), 1.3% and 1.0% of practices, respectively, had >20 providers. Sensitivity analysis excluding single-physician practices as "secondary" confirmed findings, with primary care and psychiatrist practices of >20 providers comprising, respectively, only 19.4% and 8.8% of practices (difference: P<0.0001). In secondary analyses, bipolar disorder was used as a tracer condition to estimate practice census for a high-complexity, high-cost behavioral health condition; only 1.3-18 patients per practice had claims for this condition.
  
  
  CONCLUSIONS
  The tax identification number method for estimating practice size has strengths and limitations that complement those of survey methods. The proportion of practices below the lower bound of prior CMP studies is substantial, and care models and policies will need to address the needs of such practices and their patients. Achieving a critical mass of patients for disorder-specific CMPs will require coordination across multiple small practices.
authors: Department of Psychiatry, Harvard Medical School & Center for Organization, Leadership, & Management Research (COLMR), VA Boston Healthcare System, Boston, MA 02130, USA. mark.bauer@va.gov
authors: Mark S
authors: MS
authors: Bauer
authors: Deane
authors: D
authors: Leader
authors: Hyong
authors: H
authors: Un
authors: Zongshan
authors: Z
authors: Lai
authors: Amy M
authors: AM
authors: Kilbourne
mesh_terms: D003625:Data Collection / Q000379:methods; D018166:Health Care Reform; D006801:Humans; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D008605:Mental Health Services / Q000458:organization & administration* / Q000706:statistics & numerical data; D010818:Practice Patterns, Physicians'; D011320:Primary Health Care / Q000458:organization & administration* / Q000706:statistics & numerical data; D011570:Psychiatry / Q000706:statistics & numerical data; D011787:Quality of Health Care / Q000458:organization & administration* / Q000706:statistics & numerical data; D014481:United States