ABSTRACT

Objectives: To assess the impact of angiotensin receptor blocker (ARB) switching among patients with controlled blood pressure (BP) on changes in BP and BP control rates as well as physician offi ce visits and other antihypertensive medication modifi cations.

Study Design: A retrospective study was conducted using the General Electric centricity electronic medical records of a primary care physician group.

Methods: Hypertensive patients aged >18 years, with controlled BP (<130/80 mm Hg diabetes/renal impairment; <140/90 mm Hg all others) and receiving ARB therapy, were included. Switch must have occurred after the patient was on the fi rst ARB for at least 60 days. The nonswitch cohort also had controlled BP at baseline and remained on the same ARB throughout the study period.

Results: A total of 4851 patients were given an ARB between 2004 and 2008. Switchers (n = 129) and nonswitch cohort (n = 129) with controlled BP at baseline were extracted from 714 matched pairs. Matching was done on the duration of initial ARB therapy and presence of diabetes or renal impairment. There was no difference in mean baseline SBP for switchers (125.55 ± 13.84) and nonswitch cohort (124.30 ± 11.37), but switchers had higher post-switch SBP (131.94 ± 14.39) than nonswitch cohort (127.25 ± 14.57) (P = .010). More switchers lost control from index to fi rst visit post-index period (31.8%) than control (22.5%) (P = .093), and more antihy-pertensive agents were added to switchers’ regimens (1.58 ± 1.5) than controls (0.98 ± 1.1) following the switch (P <.001).

Conclusions: This study demonstrates that non-medical switches may result in loss of BP control and lead to additional medical resource use and cost. Careful consideration should be given before switching ARB therapy in patients with controlled BP.

(Am J Pharm Benefi ts. 2012;4(4):e81-e87)

Original R

esearch

Hypertension is among the most prevalent chronic

medical conditions and affects nearly 74.5 million

Americans 20 years and older.1 Hypertension is a

major risk factor for cardiovascular mortality, yet only 33% of

treated patients with hypertension achieve adequate blood

pressure (BP) control.2 In most patients, hypertension re-

mains above national guidelines, increasing the risk for heart

failure, stroke, coronary heart disease, and kidney failure.3

The incremental direct medical expenditures of hyperten-

sion in the United States are estimated at $55.0 billion,4 with

additional expenditures estimated at $14 to $18 billion in

indirect costs.5

The Seventh Report of the Joint National Committee on

Prevention, Detection, Evaluation and Treatment of High

Blood Pressure (JNC 7) contains guidelines which recom-

mend the use of thiazide-like diuretics, calcium-channel

blockers (CCBs), angiotensin-converting enzyme inhibitors

(ACEIs), angiotensin receptor blockers (ARBs), beta-block-

ers, or combination therapies as fi rst-line treatment choices.6

Based on clinical evidence and economic outcomes, the use

of newer agents such as CCBs and ARBs has increased in

recent years, and they account for a signifi cant portion of all

antihypertensive prescriptions in the United States.7 The clas-

sic “step therapy” treatment paradigm of prescribing 1 drug

and progressively increasing the drug’s dosage to reduce BP

is now considered to be inadequate in achieving BP control

in most patients with uncontrolled hypertension or among

those with compelling indications (eg, diabetes, heart fail-

ure, post-myocardial infarction, and chronic kidney disease).

Consequently, such patients often require multiple titrations

and/or combination therapy to improve BP goal–attain-

ment rates.3,8 While such therapy modifi cations to achieve

BP control are necessary, changes for non-medical reasons

such as cost, especially among patients who are adequately

controlled, should be done with caution. It is estimated

that switches for non-medical (eg, formulary) reasons are

more common among patients with hypertension than for

At a GlancePractical Implications e82

Author Information e86

Web Exclusive www.ajpblive.com

Switching Between Different ARBs in Patients With Controlled BP

Khalid M. Kamal, PhD; Christopher Zacker, RPh, PhD; and Louis Civitarese, DO

www.ajpblive.com    Vol. 4, No. 4  •  The American Journal of Pharmacy Benefi ts e81

P R A C T I C A L I M P L I C A T I O N S

The study examined the clinical and economic implications of switching angiotensin receptor blocker therapy in patients with controlled blood pressure (BP). The results demonstrate that these switches may result in higher post-switch BP, possibly leading to loss of BP control and use of additional medical resources.

n There is an association between switching among treatments and increase in healthcare resources and costs.

n If the patient’s condition is inadequately controlled after the switch, it can potentially lead to additional office visits, telephone contacts, extra tests, and discarded medications.

n In the absence of clear guidelines on the practice of switching in controlled patients, careful consideration should be given to the potential benefits and costs before switching therapies.

e82    The American Journal of Pharmacy Benefits  •  July/August 2012                                      www.ajpblive.com

n  Kamal • Zacker • Civitarese

treatment of other chronic diseases.9 However, changes

to patients’ antihypertensive drug regimens could poten-

tially result in loss of BP control, an increase in frequency

of adverse events, and even increased treatment costs.9,10

As the cost of medical care and prescription medi-

cines continues to increase, formulary restrictions and in-

creased patient cost sharing are being used with greater

frequency to contain costs. As health plans and other

payers negotiate rates for branded antihypertensive prod-

ucts, agents listed on “preferred drug lists” can change,

resulting in products changing formulary tier and, con-

sequently, copay amounts. Therapeutic switches without

an underlying medical reason are not uncommon, even

among patients who are effectively controlled with phar-

macotherapy.11,12 Although the specific rationale for these

substitutions is not known with certainty, such decisions

may occasionally be made from a cost perspective, with-

out adequate consideration given to the clinical implica-

tions. From a clinical perspective, the impact of switching

on treatment safety or effectiveness must be evaluated,

while from an economic perspective, additional utiliza-

tion of healthcare resources should be assessed.

Although therapeutic switches in ARB therapy may

occur due to changes in health plan formularies or drug

availability, little information is available to guide these

switches or to evaluate the impact of these switches on

clinical and economic outcomes in an actual practice set-

ting. The purpose of this study was to assess the “real-

world” use of ARBs in the treatment of hypertension and

the consequences, both clinical and economic, of switch-

ing between agents within the ARB class. This retrospec-

tive study uses electronic medical record data to evaluate

patients who had controlled BP and yet were switched

from the initially prescribed ARB to a different ARB to

determine whether the new ARB provides equivalent and

adequate BP control. A secondary objective was to as-

sess whether additional medical resource utilization was

observed subsequent to the therapeutic switch.

METHODSData Source

Patients were retrospectively identified from the

GE Centricity Electronic Medical Records (EMRs) da-

tabase of a primary care physician group. At the time

of the analysis, the database contained approximately

75,000 active patients receiving care from 34 primary

care providers in Southwestern Pennsylvania. The EMR

database allowed the capture of data from patient re-

cords including demographics and clinical diagnoses,

prescribed medications, procedures, and laboratory test

results. Since the data are captured at every visit, lon-

gitudinal follow-up and measurement of clinical out-

comes and resource use is possible for each patient.

Study PopulationPatients were included in the study if they were >18

years of age, had been continuously seen by the physi-

cian group, had visited a participating physician’s office

during the 4-year period (2004-2008), had a recorded

diagnosis of hypertension (International Classification

of Diseases, Ninth Revision, Clinical Modification: 401.

xx), and had initiated ARB therapy. Patients who had

switched from one ARB to another ARB (index date)

and remained on the second ARB for the duration of the

study period (6 months) were identified. Eligible patients

were required to have both a recorded BP reading on

the index date and a subsequent measurement during

the follow-up period. Patients with only 1 observation

either before or after the index date were excluded from

the study.

“Switchers” were identified as those patients who had

switched from one ARB to a different ARB. Switching

from an ARB to an ARB/hydrochlorothiazide combina-

tion was not considered to be a switch unless the ARB

component differed. Patients were required to have had

an initial ARB prescribed for them for at least 60 days

before the switch to a different ARB occurred. The se-

lection of this time period (60 days) was based on the

assumption that a patient would be stabilized on the first

ARB during this time period, thus offering some assur-

ance that the switch did not occur due to intolerance. The

nonswitch cohort consisted of patients who remained on

the same initial ARB therapy and did not switch. To re-

duce the potential influence of confounding variables,

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Switching Between Different Angiotensin Receptor Blockers

the nonswitch cohort was matched with the switchers

on the duration of initial ARB therapy and the presence/

absence of diabetes or a chronic kidney condition. The

date of the ARB switch was identified as the index date

for switchers. The index date for the nonswitch cohort

was the matched index date with the switchers with a

2-month window in duration to allow easier matching

between the 2 cohorts. Two 6-month periods were then

identified around the index date: a 6-month pre-period

and a 6-month follow-up period to capture clinical and

economic outcomes (Figure).

Study OutcomesThe outcomes of interest included systolic (SBP) and

diastolic blood pressure (DBP) measurements at baseline

(pre-index) and post-index, number of office visits (post-

index), and addition of other non-ARB antihypertensive

medications (post-index). At least 2 valid BP readings

were required for each patient, with baseline or pre-index

reading being the most recent reading prior to the switch

and post-index reading being the first reading after the

switch. “BP Control” was defined as BP of <140/90 mm

Hg for all patients except <130/80 mm Hg for diabetic

patients or those with renal conditions. Based on the

changes to SBP and DBP, the percent of patients that lost

BP control, gained BP control, or maintained the same

BP control status from index to first visit post-period was

calculated. In addition, the mean number of non-ARB

antihypertensive agents added in the post-index period

for switchers and nonswitchers, and the number of of-

fice visits during the post-index dates, were measured.

A number of other demographic and clinical variables

such as age, gender, and presence of comorbid condi-

tions (eg, diabetes and renal conditions) were included

in the analyses for statistical control.

Statistical Analyses Descriptive statistics were conducted across the

2 cohorts. Independent t tests were employed for

comparisons of continuous variables, such as BP mea-

surements and the number of office visits. χ2 tests were

used to compare categorical variables, such as changes

to antihypertensive therapy before and after the switch,

compared with the nonswitch cohort. Additional analysis

using covariance (ANCOVA) with controlled potentially

confounding factors such as age, gender, patient’s diabe-

tes and renal status, and numbers of days patients were

on ARB was conducted. Data from the EMR database

were extracted using Microsoft SQL, and all statistical

analyses were conducted using SPSS version 18.0 (SPSS

Inc, Chicago, Illinois). A P value of <.05 was considered

statistically significant. The study was approved by the

Institutional Review Board at Duquesne University (Pitts-

burgh, Pennsylvania).

RESULTSInitial review of the EMR database identified 4851

patients with hypertension who were given an ARB be-

tween 2004 and 2008. A total of 656 (13.52%) patients

were switched from one ARB to another, for any reason,

during that time period. Based on the inclusion/exclusion

criteria, 357 matched pairs of switchers and nonswitchers

were identified using a 1:1 matching based on the dura-

tion of ARB treatment and the presence/absence of dia-

betes/renal condition. The mean age of the switchers was

69.18 + 13.37 years and the nonswitch cohort was 65.72

+ 14.33 years (P <.001). Overall, 62.2% of the switchers

were females compared with 58.0% of the nonswitch co-

hort (P = .252). The 2 cohorts were comparable on base

days (numbers of days patients were on ARB), preva-

lence of diabetes or renal conditions, and pre-index SBP.

Since the goal of the study was to assess the impact

of ARB switch on changes in BP, switchers (n = 129) and

their matched control nonswitchers (n = 129) who had

controlled BP at baseline (<130/80 diabetes/renal impair-

ment; <140/90 all others) were extracted from the 357

matched pairs. There were no statistically significant dif-

ferences between the 2 groups in the duration of the ARB

Figure. Study Time Frame

2004 to 2008

Index date

BP closest to index date usedfor baseline

First BP reading after index date (6 months)

6 months 6 months

BP indicates blood pressure. Baseline or pre-index reading was the most recent reading prior to the switch and post-index reading was the first reading after the switch within 6-month period. BP control was defined as BP of <140/90 mm Hg for all patients except <130/80 mm Hg for diabetic patients or those with renal conditions.

e84    The American Journal of Pharmacy Benefits  •  July/August 2012                                      www.ajpblive.com

n  Kamal • Zacker • Civitarese

treatment and the presence/absence of diabetes/renal

condition (Table 1). The mean age of the switchers was

69.28 + 13.23 years and the nonswitch cohort was 66.17

+ 14.55 years (P = .232). Overall, 58.9% of the switch-

ers were females compared with 61.9% of the nonswitch

cohort (P = .443).

Table 2 details the baseline SBP and DBP, loss of BP

control in the post-index period, and changes in resource

utilization (post-index) in patients who had controlled

BP at baseline (univariate analysis). There was no dif-

ference in mean baseline SBP for switchers (125.55 +

13.84) and nonswitch cohort (124.30 + 11.47) but switch-

ers had higher post-switch SBP (131.94 + .39) than non-

switch cohort (127.25 + 14.57) (P = .010). More switchers

lost control from index to first visit post-index period

(31.8%) than control (22.5%), although this finding was

not statistically significant (P = .093). In the post-index

period, more non-ARB antihypertensive agents were

added in switchers (1.58 + 1.5) than control (0.98 + 1.1)

(P <.001). Also, switchers had a

slightly higher number of post-

index office visits (2.91 + 3.13)

compared with the nonswitch

cohort (2.54 + 1.79), but the

difference was not statistically

significant (P = .239).

Adjusted means and con-

fidence intervals (CIs) for

post-switch SBP and DBP and

post-index changes in resource

utilization from ANCOVA

analysis after controlling for

influencing factors such as age,

gender, patient’s diabetes and renal status, and number

of days patients were on ARB are reported in Table 3.

Switchers had higher post-switch SBP (131.70 + 1.22; 95%

CI 129.31-134.10) than nonswitch cohort (127.63 + 1.22;

95% CI 125.23-130.03) (P = .019). There was no significant

difference in post-switch DBP between switchers (77.35

+ 0.76; 95% CI 75.8-78.8) and nonswitch cohort (76.64 +

0.76; 95% CI 75.1-78.2) (P = .525). In the post-index pe-

riod, more non-ARB antihypertensive agents were added

in switchers (1.58 + 0.12; 95% CI 1.35-1.81) than control

(0.98 + 0.12; 95% CI 0.75-1.21) (P <.001). There was no

significant difference in post-index office visits between

switchers (2.77 + 0.215; 95% CI 2.35-3.19) and nonswitch

cohort (2.69 + 0.215; 95% CI 2.27-3.11) (P = .798).

Table 4 reports the results from a paired sampled t

test that provides the within-group changes in pre- and

post-index SBP and DBP. Although both groups showed

an increase in the SBP, the increase in SBP (as reported

by mean differences) was higher for switchers (6.388;

P = .001) compared with the

nonswitch cohort (2.946; P =

.025). For DBP, the mean dif-

ferences for switchers was sta-

tistically significantly different

(1.829; P = .025) whereas the

pre- and post-differences were

not statistically significant for

the nonswitch cohort (1.481; P

= .107).

DISCUSSIONThis study examined the

clinical and economic implica-

tions of switching ARB therapy

in patients with controlled BP.

The results demonstrate that

Table 1. Patient Characteristics for the Subset of Patients With Controlled Blood Pressure at Baseline (n = 258)

Switchers Nonswitch Cohort P

N 129 129

Age (mean ± SD) 69.28 ± 13.23 y 67.27 ± 13.68 y 0.232a

Gender Male 53 (41.1%) 47 (36.4%) 0.443b

Female 76 (58.9%) 82 (63.6%)

Base days 470.78 ± 370.08 534.11 ± 380.66 0.177a

Diabetes or renal condition

Yes 30 (23.3%) 24 (18.6%) 0.359b

Base days indicates numbers of days patients were on angiotensin receptor blocker therapy; SD, standard deviation. aIndependent t test, P <.05. bχ2 Test, P <.05.

Table 2. Study Outcomes Among Patients With Controlled Blood Pressure at Baseline [Univariate Analysis] (n = 258)

Switchers Nonswitch Cohort P

SBP (mean ± SD) Pre-index 125.55 ± 13.84 124.30 ± 11.47 .431

Post-index 131.94 ± 14.39 127.25 ± 14.57 .010a

DBP (mean ± SD) Pre-index 75.46 ± 9.05 75.22 ± 9.22 .833

Post-index 77.29 ± 10.12 76.70 ± 10.54 .648

Stayed the sameb 88 (68.2%) 100 (77.5%) .093

Lost controlc 41 (31.8%) 29 (22.5%) .093

Other antihypertensive medications (mean ± SD)

Post-index 1.58 ± 1.49 0.98 ± 1.11 .001a

Office visits (mean ± SD) Post-index 2.91 ± 3.13 2.55 ± 1.79 .239

DBP indicates diastolic blood pressure; SBP, systolic blood pressure; SD, standard deviation. aIndependent t test, P <.05. bStayed the same: a patient was considered to have “stayed the same” if the blood pressure readings remained high to high or low to low. cLost control: a patient was considered to have “lost control” if the blood pressure readings went from low to high.

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Switching Between Different Angiotensin Receptor Blockers

switching patients

who have controlled

BP may result in

higher post-switch

BP, possibly leading

to loss of BP control

and use of additional

medical resources.

The JNC 7 recom-

mends regular moni-

toring and follow-up

of patients initiating

new antihyperten-

sive medications un-

til their BP goals are

achieved.3 Since clear guidelines do not exist on thera-

peutically equivalent and interchangeable doses of differ-

ent ARBs, patients who have switched ARB therapy may

still require additional follow-up for dose titrations or ad-

ditional antihypertensive agents, leading to the increased

medication use and office visits observed in this study.

Few studies have been reported in the literature that

evaluated the clinical and economic impact of switches

within the ARB class. Even though this study did not quan-

tify the economic consequences of additional antihyper-

tensive medications and office visits, other ARB-related

studies have shown that switching medications can ap-

parently affect clinical outcomes and the unintended eco-

nomic consequences may go beyond the drug acquisition

costs alone.11-14 Usher-Smith and colleagues (2007) in the

United Kingdom assessed the cost savings and patients’

perspective of switching patients (n = 115) from losar-

tan to candesartan.11 At the end of the study, 7 patients

switched back to losartan and among those that stayed

on candesartan, there was a slight reduction in BP with

no adverse events attributable to the switch. The annual

savings was estimated at £13,374.40. However, the au-

thors cautioned that individual patients’ attitudes should

be carefully considered by physicians prior to switching,

since many of the patients were reportedly annoyed at the

idea of switching between drugs.11 Graham and Allcock

(2002) evaluated the clinical outcomes in patients who

were switched from losartan or valsartan to irbesartan.12

Mean BP before and after the switch was similar in pa-

tients during the conversion process. Also, no serious ad-

verse events were reported, although a higher number of

patients (34 out of 79) discontinued irbesartan due to the

incidence of adverse events.12 An administrative claims

database study by Signorovitch and colleagues (2010) es-

timated that patients who were switched from valsartan

to other ARBs without any medical reasons incurred 19.1

additional outpatient visits per 100 patients, 9.3 additional

hypertension-related inpatient days per 100 patients, and

a higher medical cost of $748 per patient compared with

$492 per patient for nonswitchers.13 Another claims-based

analysis of a US managed health plan’s enrollees demon-

strated that switching among ARBs was associated with

a statistically significant greater all-cause health services

cost than those who remained on the same ARB medica-

tion ($6286 vs $5701, respectively).14

A survey of healthcare providers in a long-term care set-

ting highlighted the concerns about non-medical switch-

ing that were based on formulary restrictions.9 Nurses,

pharmacists, and physicians reported that switching was

common in patients with hypertension, and the practice

of switching was perceived to increase administrative

time, side effects, and overall risk of costly outcomes.9 If

the patient’s condition is inadequately controlled after the

switch, it can potentially lead to additional office visits,

telephone contacts, extra laboratory and diagnostic tests,

discarded medications, hospital and emergency depart-

ment visits, and even loss of productivity.10 The associa-

tion between switching among treatments and increase in

healthcare resources and costs has also been reported for

statins, antidepressants, and antiepileptics.13

These findings highlight the challenges and potential

pitfalls in implementing cost-control mechanisms, such as

tiered pharmacy benefits, that strive to achieve healthcare

cost savings by influencing patient cost-sharing to drive

patients toward less costly agents. While savings may be

engendered on the impacted prescription product, it is

worth considering that savings generated may be more

than offset by increased healthcare costs. In the absence

of clear guidelines on the practice of switching in pa-

tients who are controlled, careful consideration should be

Table 3. Post-Index Study Outcomes Among Patients With Controlled Blood Pressure at Baseline [ANCOVA Analysis] (n = 258)

Adjusted Mean ± SD CI (95%) P

SBP Switcher 131.70 ± 1.22 129.31-134.10 .019a

Nonswitch 127.63 ± 1.22 125.23-130.03

DBP Switcher 77.35 ± 0.76 75.8-78.8 .710

Nonswitch 76.64 ± 0.76 75.1-78.2

Other antihypertensive medications Switcher 1.58 ± 0.12 1.35-1.81 .001a

Nonswitch 0.98 ± 0.12 0.75-1.21

Office visits Switcher 2.77 ± 0.22 2.35-3.19 .798

Nonswitch 2.69 ± 0.22 2.27-3.11

CI indicates confidence interval; DBP, diastolic blood pressure; SBP, systolic blood pressure; SD, standard deviation. ANCOVA analysis: controlled for age, gender, base days, and presence/absence of diabetes or renal conditions. aSignificant at P <.05.

e86    The American Journal of Pharmacy Benefits  •  July/August 2012                                      www.ajpblive.com

n  Kamal • Zacker • Civitarese

given to the potential benefits and costs before switching

therapies. Several factors should be taken into account

before making these switches: with respect to within-

class substitution, evidence on the effectiveness, safety,

and different indications for different ARBs needs to be

carefully considered.10 Reports on the clinical effective-

ness of different ARBs in patients with hypertension are

mixed. Two meta-analyses reported no differences in the

BP-lowering effects of different ARBs15,16 while a third

study showed significant differences between ARBs.17 In

addition, the indications vary among agents in the ARB

class, making it important for clinicians to base their pre-

scribing decisions on patient comorbidities and clinical

evidence rather than on the assumptions of effectiveness

and safety equivalency of different ARBs.10

The results of our study should be interpreted in the

context of the real-world data used in the study. The

main limitation is that our results are based on a patient

population and data of 1 physician group from a limited

geographical area, and may not be generalizable to other

populations or even those practices that do not have

EMR. In addition, there may have been differences in the

evaluation of patients by different providers within the

practice itself or differences in the availability and cost of

different ARBs available on local managed care formu-

laries. Second, patient adherence and persistence with

medications could not be assessed in our retrospective

analysis using EMR data. Although it is well established

that poor adherence results in additional resource use

and costs, the impact of switching on patient adherence

and persistence has been largely ignored. The reported

use of the medications by the patients actually reflects

the prescriptions written by the physicians, and thus the

initiation of the therapy is

assumed. Any assumption

regarding differences in

clinical outcomes due to

differences in patient ad-

herence rather than effica-

cy reflects the real-world

practice. Third, the use

of a single pre- and post-

index BP measurement

could be a limitation,

and alternatives (such as

multiple measurements)

could produce differing

results. However, given

the structure of the EMR

database and comparison

of 2 groups, the use of single pre- and post-index BP

measurement was considered a consistent measure. We

were unable to ascertain the reason for each switch, and

the assumption was made that switches resulted from for-

mulary-related considerations; it is difficult to know the

impact of this assumption or how this may have affected

our study’s findings. Some important information was not

available for analysis, such as duration of hypertension,

number and severity of all cardiovascular-related comor-

bid conditions, use of other medications which may af-

fect BP, and patient body mass index, and it is difficult

to know the role these covariates may have played in BP

control. Nevertheless, our study provides useful informa-

tion regarding the potential impact of switching from one

ARB to another agent within the class.

In summary, careful consideration should be given

before switching patients with controlled BP between

drugs within the same antihypertensive class, with such

switches warranting the same consideration as any other

change in medication regimen. Our study demonstrates

that switching in controlled patients may result in unin-

tended clinical and economic outcomes.

Author Affiliations: From Department of Pharmacy Administration (KMK), Duquesne University, Mylan School of Pharmacy, Pittsburgh, PA; Novartis Pharmaceuticals Corporation (CZ), Emmaus, PA; Preferred Pri-mary Care Physicians (LC), Oak Manor, Pittsburgh, PA.

Funding Source: The study was sponsored by Novartis Pharmaceu-ticals Corporation.

Author Disclosures: Dr Zacker reports employment and stock ownership with Novartis Pharmaceuticals Corporation, the funder of the study. The other authors (KMK, LC) 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 (KMK, CZ, LC); ac-quisition of data (KMK, LC); analysis and interpretation of data (KMK,

Table 4. Study Outcomes Among Patients With Controlled Blood Pressure at Baseline and Post Index [Within-Group Differences] (n = 258)

Mean ± SD Mean Difference CI (95%) P

Switcher

Baseline SBP 125.55 ± 13.84

SBP at post index 131.94 ± 14.39 6.388 9.40-3.38 .001a

Baseline DBP 75.46 ± 9.05

DBP at post index 77.29 ± 10.12 1.829 3.42-0.24 .025a

Nonswitch

Baseline SBP 124.30 ± 11.47

SBP at post index 127.25 ± 14.57 2.946 5.52-0.38 .025a

Baseline DBP 75.22 ± 9.22

DBP at post index 76.70 ± 10.54 1.481 3.28-0.32 .107

CI indicates confidence interval; DBP indicates diastolic blood pressure; SBP, systolic blood pressure; SD, standard deviation. Paired sample t test. aSignificant at P <.05.

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Switching Between Different Angiotensin Receptor Blockers

CZ, LC); drafting of the manuscript (KMK, CZ); critical revision of the manuscript for important intellectual content (KMK, LC); statistical analy-sis (KMK); provision of study materials or patients (KMK, LC); obtaining funding (KMK, CZ); administrative, technical, or logistic support (KMK); and supervision (KMK, CZ).

Address correspondence to: Khalid M. Kamal, PhD, 418 B Mellon Hall, Mylan School of Pharmacy, 600 Forbes Ave, Duquesne University, Pittsburgh, PA 15282. E-mail: kamalk@duq.edu.

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