The Medical Home: What Do We Know, What Do We Need to Know? A Review of the Earliest Evidence on the Effectiveness of the Patient-Centered Medical Home Model

March 2013
AHRQ Publication No. 12(14)-0020-1-EF
Prepared For:
Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services, 540 Gaither Road, Rockville, MD 20850,

Contract Numbers: HHSA290200900019I/HHSA29032002T, HHSA290200900019I/HHSA29032005T
Prepared By: Mathematica Policy Research, Princeton, NJ; Aparajita Zutshi, Ph.D., Deborah Peikes, Ph.D., M.P.A., Kimberly Smith, Ph.D., M.P.A., Melissa Azur, Ph.D. (Mathematica Policy Research),  Janice Genevro, Ph.D., Michael Parchman, M.D., David Meyers, M.D. (Agency for Healthcare Research and Quality).
Table 11. Summary of evidence on emergency department use
 Statistically SignificantInconclusive
InterventionFavorableUnfavorableNot Statistically SignificantUncertain Statistical Significance

Notes: A result is considered statistically significant if p<0.05. The effects reported here are point estimates; the true effects can lie anywhere within the confidence intervals around these estimates, and may well be different from the point estimate. We do not include the confidence intervals because not all studies reported them.

aBecause the statistical significance of findings on the odds of hospital use in the CMP evaluation did not take clustering into account, we made this adjustment by using ICC estimates from the literature. However, we found that the statistical significance of these findings was sensitive to the estimate of ICC used; the findings remained significant when some estimates of ICC were used but lost their significance when other estimates were used. Therefore, we consider the statistical significance of these findings to be uncertain.

bThe p-values for findings on hospital stays for the GRACE evaluation were adjusted for clustering using a range of estimates of the intracluster correlation (ICC) from the literature. The findings remained statistically significant after the adjustment.


Care Management Plusaa  Year 1: Odds of an ED visit among all patients, patients without diabetes, and patients with diabetes
Year 2: Odds of an ED visit among patients with diabetes
Year 2: Odds of an ED visit among all patients and patients without diabetes
Geriatric Resources for Assessment and Care of EldersbYear 2: Reduced number of visits by 24% among all patients and by 35% among high-risk patients Year 1: Number of visits among all patients and high-risk patients 
Guided Care  8 Months;
20 Months: Number of visits