Complexity of ambulatory care across disciplines.

Background: Complexity of care has implications for quality of care, health costs, medical errors, and patient and physician satisfaction. The objective was to compare complexity of ambulatory care across 14 medical specialties.

Methods: This secondary analysis uses the 2010 National Ambulatory Medical Care Survey, which used a multistage probability design of primary sampling units throughout U.S. ambulatory practices across 14 specialties. Sampling weights enable results from 29,179 ambulatory visits to represent 878,653,561 visits. Data included symptoms, diagnoses, diagnostic procedures, and treatments provided. Measures of input, output and total encounter complexity and hourly complexity densities were computed.

Results: Internal Medicine leads in total input and total encounter complexity with Family Medicine second in total encounter complexity. When duration-of-visit is considered, Family Medicine is the most complex discipline while Internal Medicine is the second most complex. Pediatrics lacks the complexity of Family Medicine and General Internal Medicine, and OB/GYN bears little similarity to Family Medicine or General Internal Medicine.

Conclusions: Family Medicine and Internal Medicine encounters are the most complex overall, especially when duration-of-visit is considered.

Implications: Revaluing payments based on complexity could bring better balance to cognitive and procedural services, and better meet the needs of people receiving insurance under the ACA.