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The American Journal of Managed Care September 2018
Food Insecurity, Healthcare Utilization, and High Cost: A Longitudinal Cohort Study
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Alicia Fernandez, MD; E. Margaret Warton, MPH; Dean Schillinger, MD; Howard H. Moffet, MPH; Jenna Kruger, MPH; Nancy Adler, PhD; and Andrew J. Karter, PhD
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Joanne E. Brady, PhD; Claudia Vellozzi, MD, MPH; Susan Hariri, PhD; Danielle L. Kruger, BA; David R. Nerenz, PhD; Kimberly Ann Brown, MD; Alex D. Federman, MD, MPH; Katherine Krauskopf, MD, MPH; Natalie Kil, MPH; Omar I. Massoud, MD; Jenni M. Wise, RN, MSN; Toni Ann Seay, MPH, MA; Bryce D. Smith, PhD; Anthony K. Yartel, MPH; and David B. Rein, PhD
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Dhruv Khullar, MD, MPP, and Rainu Kaushal, MD, MPH
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Health Literacy, Preventive Health Screening, and Medication Adherence Behaviors of Older African Americans at a PCMH
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Fragmented Ambulatory Care and Subsequent Healthcare Utilization Among Medicare Beneficiaries
Lisa M. Kern, MD, MPH; Joanna K. Seirup, MPH; Mangala Rajan, MBA; Rachel Jawahar, PhD, MPH; and Susan S. Stuard, MBA
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Melony E. Sorbero, PhD, MS, MPH; Susan M. Paddock, PhD; Cheryl L. Damberg, PhD; Ann Haas, MS, MPH; Mallika Kommareddi, MPH; Anagha Tolpadi, MS; Megan Mathews, MA; and Marc N. Elliott, PhD

Fragmented Ambulatory Care and Subsequent Healthcare Utilization Among Medicare Beneficiaries

Lisa M. Kern, MD, MPH; Joanna K. Seirup, MPH; Mangala Rajan, MBA; Rachel Jawahar, PhD, MPH; and Susan S. Stuard, MBA
Among Medicare beneficiaries, the relationship between fragmented ambulatory care and subsequent emergency department visits and hospital admissions varies with the number of chronic conditions.
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In this study of Medicare FFS beneficiaries 65 years and older, having highly fragmented care (in the highest quintile of fragmentation scores) seemed to have the greatest impact on subsequent outcomes, suggesting a potential threshold effect. Those with highly fragmented care had a median of 13 ambulatory visits with 8 providers, and their most frequently seen provider typically accounted for just 24% of ambulatory visits. The relationship between highly fragmented care and subsequent outcomes varied by the number of chronic conditions.

Among those with 1 to 2 or 3 to 4 chronic conditions, having the most (vs the least) fragmented care significantly increased the hazard of an ED visit and, separately, increased the hazard of a hospital admission (P <.05 for each comparison). Among those with 5 or more chronic conditions, having the most (vs the least) fragmented care significantly increased the hazard of an ED visit but decreased the hazard of a hospital admission (P <.05 for each comparison). This observation could mean that having many providers for these complex patients is often necessary and sometimes protective. We did not find an association between fragmentation and ED visits or hospital admissions among those with 0 chronic conditions, perhaps because those who are relatively healthy are not as vulnerable to the adverse effects of fragmented care.

Our finding of an increased hazard of ED visits for those with fragmented care and at least 1 chronic condition is consistent with findings from 2 other studies, which were disease-specific: 1 that focused on patients with diabetes7 and another that focused on patients with diabetes, congestive heart failure, or chronic obstructive pulmonary disease.6 Our finding of an increased hazard of hospital admissions for those with fragmented care and 1 to 4 chronic conditions is also consistent with studies that expressed the increased hazard as a function of a 0.1-point increase on a continuous fragmentation scale.6,8 Thus, our work expands the literature by including Medicare beneficiaries regardless of disease type and by quantifying the magnitude of the hazard for the most fragmented care.

The results have implications for the design of future interventions to improve healthcare, in terms of which patients to target for intervention. Many previous efforts to improve healthcare quality and efficiency have targeted the sickest patients,24,25 which makes sense, because these patients account for a disproportionate amount of healthcare utilization.26 However, the effectiveness of these programs has been mixed,24,27 perhaps in part because it is difficult to modify the need for care among the sickest patients. Our study findings suggest that there may be inefficient utilization of healthcare services among those with a moderate number of chronic conditions. Inefficient utilization may be modifiable, and decreasing inefficiency among the many people with a moderate disease burden may have a large aggregate impact.

The results of this study also have implications for what kinds of future interventions to test. Previous efforts to improve care coordination, such as the patient-centered medical home model of care, have not specifically measured or targeted patterns of ambulatory care within individual patients.28 The few previous studies that tried to explicitly decrease fragmentation were small trials but had promising results. A randomized controlled trial of 776 men 55 years and older at a Veterans Administration hospital in Vermont found that those who were randomized to “continuity” (routinely scheduled appointments with the same provider) had fewer emergent hospital admissions and shorter average length of stay than those randomized to “discontinuity” (a die tossed at each scheduled follow-up visit, with a 33% chance of being sent to a different provider).29 A randomized controlled trial of 409 pediatric patients in Seattle, Washington, was successful in decreasing fragmentation through the use of custom alerts built into electronic health records, notifying providers in real time if they were seeing patients with highly fragmented care.30


This study has several limitations. First, it is observational, and we cannot rule out unmeasured confounding. Second, we cannot draw conclusions about the medical appropriateness of the care patterns observed. It is possible that fragmentation increases appropriately when patients become acutely ill and that this appropriate use of multiple providers occurs just prior to an ED visit or hospital admission. Future studies with more granular clinical data are needed to help clarify issues of appropriateness. Third, we did not measure communication across physicians. Although having fragmented care may increase the risk of gaps in communication across providers, its presence should not be interpreted as a definite lack of care coordination. Fourth, we did not have data on practice characteristics or practice affiliation, so we were not able to account for those. Fifth, this study took place in 1 region, which may limit generalizability; however, this region is a multipayer, multiprovider healthcare market, which may make it similar to other communities. Future studies could include market characteristics (such as rural vs urban and number of providers per population) as additional explanatory variables. Sixth, this study included only FFS Medicare beneficiaries; results may not apply to patients with other insurance types.

Even with these limitations, this study is relevant, because the importance of healthcare fragmentation has grown with national changes in provider reimbursement. Medicare is moving away from FFS reimbursement toward alternative payment models.31,32 These models require providers to be clinically and financially responsible for all of a patient’s care, not just the care that they themselves provide. Thus, an excess burden of ED visits and hospitalizations from fragmented ambulatory care would be highly relevant to providers seeking to succeed under these new payment models. Large studies to explicitly test and compare the effectiveness of strategies for decreasing fragmentation are warranted. Additional studies could also consider the effect of fragmentation on rates of readmission, given that that is a time when patients are especially vulnerable to the effects of suboptimal care delivery.33-35


Highly fragmented care can independently increase the hazard of an ED visit or hospital admission, even among those with a moderate number of chronic conditions. Reducing fragmentation for those with a moderate number of chronic conditions may both improve quality and reduce costs. 


This study was funded by the Commonwealth Fund (grant #20140960). The authors thank Leah Hellerstein, BA, and Yesenia Miranda, BA, for their assistance with reviewing the literature. The authors thank the New York State Department of Health for facilitating access to the data. The conclusions do not necessarily reflect the views of the Commonwealth Fund or New York State Department of Health.

Author Affiliations: Department of Medicine (LMK, MR), and Department of Healthcare Policy & Research (LMK, JKS, RJ), Weill Cornell Medicine, New York, NY; Lake Fleet Consulting (SSS), Irvington, NY.

Source of Funding: This work was supported by the Commonwealth Fund (grant #20140960).

Author Disclosures: The authors report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (LMK, SSS); acquisition of data (LMK, RJ, SSS); analysis and interpretation of data (LMK, JKS, MR, RJ); drafting of the manuscript (LMK); critical revision of the manuscript for important intellectual content (LMK, JKS, MR, SSS); statistical analysis (JKS, MR, RJ); obtaining funding (LMK); administrative, technical, or logistic support (LMK); and supervision (LMK).

Address Correspondence to: Lisa M. Kern, MD, MPH, Weill Cornell Medicine, 525 E 68th St, Box 331, New York, NY 10065. Email:

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