J Clin Hypertens. 2018;20:429–437. wileyonlinelibrary.com/journal/jch
©2018 Wiley Periodicals, Inc.
1 | INTRODUCTION
Hypertension is the most common condition seen in primary care today.
An estimated 80 million adults older than 20 years currently have a diag-
nosis of hypertension. This represents 38.9 million physician office visits
and 3.6 million outpatient department visits annually.
Report of the Joint National Committee on Prevention, Detection,
Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines
recommend that once antihypertensive medications are started, pa-
tients should return for follow- up at monthly intervals until blood pres-
sure (BP) goals are reached and then every 3 to 6 months once stable.
The 2014 Evidence- Based Guideline for the Management of High BP in
Adults from the panel members of the Eighth Joint National Committee
(JNC 8) does not provide follow- up intervals, but does recommend that
if BP goals are not reached within a month of starting treatment, an in-
crease in the initial medication should be made or a second medication
from one of the recommended classes should be started.
Kaiser Permanente (KP) Southern California is a large, integrated
healthcare system that delivers care to approximately 4.1 million mem-
Since 2004, KP has implemented a series of changes to improve
the treatment and identification of hypertension, including: (1) creation
of a hypertension registry, (2) BP measurement standardization, (3) the
use of an evidence- based and easy- to- remember treatment algorithm,
and (4) a multidisciplinary approach to care, which includes medical
assistants, nurses, and pharmacists with shared responsibilities in BP
According to the Healthcare Effectiveness Data and
Information Set (HEDIS) from 2004 to 2012 assessing BP control at
KP, overall hypertension control increased from 54% to 86%.
The main objective of this study was to examine and describe pa-
tients with newly diagnosed hypertension and determine whether the
frequency and intervals between outpatient encounters were associ-
ated with achieving BP control. In addition, this study examined the
potential risk factors associated with the time to BP control in the first
year since hypertension diagnosis.
2 | METHODOLOGY
In this retrospective, observational, cohort study, we identified pa-
tients with newly diagnosed hypertension at KP Southern California
Association between encounter frequency and time to blood
pressure control among patients with newly diagnosed
hypertension: a retrospective cohort study
Liliana Sherman PharmD
| Mitchell A. Pelter PharmD, FCSHP, FASHP, ASH-CHC
Robert L. Deamer PharmD, BCPS
| Lewei Duan MS
| Michael Batech DrPH, MPH
Department of Pharmacy, Kaiser Permanente
Woodland Hills Medical Center, Woodland
Hills, CA, USA
Kaiser Permanente Drug Education, Ventura
County, Oxnard, CA, USA
Department of Pharmacy Administration,
Kaiser Permanente, Woodland Hills, CA, USA
Kaiser Permanente, Pasadena, CA, USA
Liliana Sherman, Department of Pharmacy,
Kaiser Permanente Woodland Hills Medical
Center, Woodland Hills, CA, USA.
This retrospective cohort study of 95 957 patients from a large integrated healthcare
organization was conducted to examine whether the frequency and intervals between
outpatient encounters were associated with achieving blood pressure (BP) control.
Patients were followed up until they were censored or achieved BP control up to
1 year. Additionally, this study examined the time to BP control. On average, follow- up
was significantly longer in patients with uncontrolled BP at 292.9 days compared with
232.2 days in those with BP control. The controlled BP group had significantly more
encounters on average compared with the uncontrolled BP group (4.1 vs 3.1, stand-
ardized difference 0.33). As the number of days increased between encounters from
the 1 to < 14 days, there was a consistently lower likelihood of achieving BP control.
ing BP control. These findings suggest that there may be an optimal number of en-
counters to benefit patients with hypertension.