Specialty use among patients with treated hypertension in a patient-centered medical home.
BACKGROUND
Little is known about how delivery of primary care in the patient-centered medical home (PCMH) influences outpatient specialty care use.


OBJECTIVE
To describe changes in outpatient specialty use among patients with treated hypertension during and after PCMH practice transformation.


METHODS
One-group, 48-month interrupted time series across baseline, PCMH implementation and post-implementation periods.


METHODS
Adults aged 18-85 years with treated hypertension.


METHODS
System-wide PCMH redesign implemented across 26 clinics in an integrated health care delivery system, beginning in January 2009.


METHODS
Resource Utilization Band variables from the Adjusted Clinical Groups case mix software characterized overall morbidity burden (low, medium, high). Negative binomial regression models described adjusted annual differences in total specialty care visits. Poisson regression models described adjusted annual differences in any use (yes/no) of selected medical and surgical specialties.


RESULTS
Compared to baseline, the study population averaged 7% fewer adjusted specialty visits during implementation (P < 0.001) and 4% fewer adjusted specialty visits in the first post-implementation year (P = 0.02). Patients were 12% less likely to have any cardiology visits during implementation and 13% less likely during the first post-implementation year (P < 0.001). In interaction analysis, patients with low morbidity had at least 27% fewer specialty visits during each of 3 years following baseline (P < 0.001); medium morbidity patients had 9% fewer specialty visits during implementation (P < 0.001) and 5% fewer specialty visits during the first post-implementation year (P = 0.007); high morbidity patients had 3% (P = 0.05) and 5% (P = 0.009) higher specialty use during the first and second post-implementation years, respectively.


CONCLUSIONS
Results suggest that more comprehensive primary care in this PCMH redesign enabled primary care teams to deliver more hypertension care, and that many needs of low morbidity patients were within the scope of primary care practice. New approaches to care coordination between primary care teams and specialists should prioritize high morbidity, clinically complex patients.
Division of General Internal Medicine and Geriatrics, Northwestern University, Feinberg School of Medicine, 750 N. Lake Shore Drive, 10th floor, Chicago, IL, 60611, USA, david.liss@northwestern.edu.
David T
DT
Liss
Paul A
PA
Fishman
Carolyn M
CM
Rutter
David
D
Grembowski
Tyler R
TR
Ross
Robert J
RJ
Reid
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000453:epidemiology*; D008511:Medicine / Q000379:methods*; D008875:Middle Aged; D018802:Patient-Centered Care / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult