Association of Medicare and Medicaid insurance with increasing primary care-treatable emergency department visits in the United States.

Objectives Policymakers have increasingly focused on emergency department (ED) utilization for primary care–treatable conditions as a potentially avoidable source of rising health care costs. The objective was to determine the association of health insurance type and arrival time, as indicators of limited availability of primary care, with primary care–treatable classification of ED visits. Methods This was a retrospective analysis of a nationally representative sample of 241,167 ED visits from the 1997 to 2009 National Hospital Ambulatory Medical Care Surveys (NHAMCS). Probabilities of ED visits being primary care–treatable were categorized based on the primary International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code. The association of health insurance type and arrival time was determined with the average probability of the primary diagnosis being primary care–treatable using multivariable linear regression. Results Compared to privately insured visits, Medicaid visits had a 1.7% (95% confidence interval [CI] = 1.2% to 2.2%) and uninsured visits a 2.4% (95% CI = 1.9% to 3.0%) higher probability of primary care–treatable classification, while Medicare visits had a 1.4% (95% CI = 0.7% to 2.0%) lower probability during the overall study period. Compared to business hours, weekend visits had a 1.5% (95% CI = 1.0% to 2.0%) higher probability of being primary care–treatable during the overall study period. From 1997 to 2009, the overall adjusted probability of ED visits being primary care–treatable increased by 0.19% (95% CI = 0.10 to 0.28) per year. This probability increased at a rate of 0.52% per year for Medicare visits (95% CI = 0.38% to 0.65%), more than double that of Medicaid visits (0.25% per year, 95% CI = 0.13% to 0.37%). By contrast, there was no significant change from 1997 to 2009 in the average probability of ED visits being primary care–treatable by privately insured (0.05% per year, 95% CI = –0.07 to 0.16) or uninsured (0.00% per year, 95% CI = –0.12 to 0.13) individuals. Conclusions These findings add to prior work that implicates insurance type and arrival time in the variation of primary care–treatable ED visits. Although primary care–treatable classification of ED visits was most associated with uninsured or Medicaid visits, this classification increased most rapidly among Medicare visits during the study period. Resumen Objetivos Los politicos se han centrado cada vez mas en la utilizacion del servicio de urgencias (SU) en patologias tratables en atencion primaria (TAP) como una fuente potencialmente evitable de incrementar los costes del sistema sanitario. El objetivo fue determinar la asociacion del tipo de seguro sanitario y el tiempo de llegada, como indicadores de disponibilidad limitada, con la clasificacion de patologias TAP de las visitas al SU. Metodologia Analisis retrospectivo de una muestra representative nacional de 241.167 visitas al SU desde 1997 a 2009 de las National Hospital Ambulatory Medical Care Surveys. Las probabilidades de visita al SU por procesos TAP se categorizaron basandose en la codificacion CIE-9-MC. La asociacion del tipo de seguro sanitario y el tiempo de llegada se determino con la probabilidad promedio de diagnostico principal de ser TAP usando un analisis multivariable de regresion lineal. Resultados En comparacion a las visitas de los asegurados de forma privada, las visitas Medicaid tuvieron un 1,7% (IC 95% = 1,2% a 2,2%) y las visitas de los no asegurados un 2,4% (IC 95%= 1,9% a 3,0%) de mayor probabilidad de clasificacion como TAP, mientras que las visitas Medicare tuvieron un 1,4% (IC 95% = 0,7% a 2,0%) de menor probabilidad durante todo el periodo del estudio. En comparacion con la horas de trabajo, las visitas los fines de semana tuvieron un 1,5% (IC 95% = 1,0% a 2,0%) de mayor probabilidad de ser TAP durante todo el periodo del estudio. Desde 1997 a 2009, la probabilidad ajustada global de visitas al SU por procesos TAP se incremento un 0,19% (IC 95% =0,10 a 0,28) por ano. Este probabilidad incremento un porcentaje de un 0,52% por ano para las visitas Medicare (IC 95% =0,38% a 0,65%), mas del doble que las visitas Medicaid (0,25% por ano, IC 95% = 0,13% a 0,37%). En contraste, no hubo un cambio significativo de 1997 a 2009 en la probabilidad media de visitas al SU por procesos TAP en los individuos asegurados de forma privada (0,05% por ano, IC 95% = –0,07 a 0,16) o no asegurados (0,00% por ano, IC 95% = –0,12 a 0,13). Conclusiones Estos resultados anaden a los trabajos previos la implicacion del tipo de seguro y el tiempo de llegada en la variacion de las visitas al SU por procesos TAP. Aunque la calificacion de TAP de las visitas al SU se asocio con visitas de los no asegurados o Medicaid, esta clasificacion incremento mas rapidamente entre las visitas Medicare durante el periodo del estudio.