Abstract
Abstract
Objective
The purpose of this study was to determine how strongly mean systolic blood pressure (mSBP, mm Hg) was related to hypertension control and if an mSBP<130 was required to achieve ≥80% control to <140/<90.
Design
mSBP and per cent control to <140/<90 at the last encounter were assessed in a cross-sectional analysis of two cohorts with hypertension: (1) randomised, controlled Systolic blood PRessure Intervention Trial (SPRINT) and (2) real-world American Medical Association’s Measure Accurately, Act Rapidly, Partner with patients Hypertension programme.
Setting
SPRINT randomised participants with hypertension to two SBP targets: <140 (standard treatment, SPRINT-S) and <120 (intensive treatment, SPRINT-I). MAP (Measure Accurately, Act Rapidly, Partner with patients) included adults with hypertension at five healthcare systems incentivised by payers to control BP to <140/<90.
Participants
SPRINT participants with year 2 data. Patients in MAP (had hypertension, were aged≥18 years, had ≥2 healthcare visits from November 2019 through October 2021 and received care from clinicians (n=544) with ≥24 patients.
Primary and secondary outcome measures
mSBP and control to <140/<90. In MAP, control to <140/<90 was assessed in clinicians grouped by 5 mm Hg increments in the mSBP of their patient panel.
Results
In SPRINT-S (n=4303) and SPRINT-I (n=4323), mSBP values at the last visit were 136.7 and 121.7 with BP<140/<90 in 61% and 88% of participants, respectively. In MAP, mSBP at the last visit (n=168 978 patients) was 132.1 with BP<140/<90 in 70% of participants. Among clinicians with participant mSBP of 120 to <125, 88% of their patients were controlled to <140/<90, similar to SPRINT-I. Control fell to 79% of patients, with clinician-level mSBP of 125 to <130, 71%, with mSBP of 130 to <135 and 57%, with mSBP of 135 to <140 (similar to SPRINT-S); mSBP accounted for 80% of variance in clinician-level hypertension control.
Conclusions and relevance
mSBP is strongly related to hypertension control. Moreover, mSBP<130 is required to attain control rates to <140/<90 in the range of 80% and higher.
Keywords: Hypertension, Blood Pressure, Cardiovascular Disease
STRENGTHS AND LIMITATIONS OF THIS STUDY.
Data sources included adults with hypertension from a rigorously designed and conducted clinical trial as well as real-world clinical settings.
The relationship of mean systolic blood pressure (BP) to control at <140/<90 mm Hg was assessed in the overall study population and by age, race (black/white) and sex.
BP measurements in the real-world setting were not consistently standardised.
Introduction
The quality of hypertension care at a population level is most often assessed by control rates to blood pressure (BP, mm Hg) <140/<90.1,3 Most clinicians globally still aim to control BP to <140/90 when treating hypertension. Increasingly, hypertension guidelines are recommending systolic BP control to <130 or lower.4,7 However, a fundamental question is, ‘What mean BP levels are needed for acceptable control rates for patients and populations?’ Given intraindividual and interindividual BP variability, an average BP of 139/89 will only control BP to <140/<90 slightly over half the time, which is suboptimal among those aiming for clinical excellence.
The definition of acceptable control rates is converging at over 80%. For example, the WHO and US Centers for Disease Control recommend a BP control rate of at least 80%.1 3 However, the mean BP required to achieve >80% control rates remains uncertain. This gap in evidence is critical, especially for clinicians aiming to attain high rates of control for their patient population and consistent control to <140/<90 for each patient. It is critical to know whether the target mean SBP (mSBP) for their patient population and individual patients should be closer to 125 than 135, for example, as lowering mSBP to an additional 10 mm Hg requires another BP drug or increasing doses of several BP drugs.8 9
The mean BP required to achieve 80% control rates can be estimated from interindividual and intraindividual BP variability, which is approximated by the SD.10 Interindividual SBP has an SD of roughly 16 mm Hg.810,12 In a normal distribution, the 84th percentile is 1 SD above the mean. Hence, an mSBP of ∼124 mm Hg would be required to attain 84% control to <140 in a population, that is, 16 mm Hg below 140. Similarly, for a patient with an intraindividual SD of 12 mm Hg,13 an mSBP of ∼128 across visits would be needed to attain SBP<140 on 84% of encounters. However, these are indirect approximations, which do not account for diastolic BP (DBP) or skewing of BP distributions. Directly observed data from clinical care are required to inform the important question of mSBP required to achieve acceptable BP control rates. Therefore, this paper aims to quantify the relationship between mSBP and hypertension control rates and, specifically, to determine what mean SBP is required for 80% or higher control to <140/<90.
Methods
Study design
The study employed a retrospective, cross-sectional analysis of two cohorts of adults with hypertension to assess the relationship of mSBP and hypertension control. The two cohorts included the Systolic blood PRessure Intervention Trial (SPRINT)8 14 15 and the Measure Accurately, Act Rapidly, Partner with patients (MAP) Hypertension programme conducted by the American Medical Association (AMA).16 This report followed the guidelines for STrengthening the Reporting of OBservational studies in Epidemiology.17
Data sources
Two de-identified data sets were accessed for this study.
SPRINT was a multicentre trial comparing clinical outcomes at two BP targets. Details on inclusion and exclusion criteria were published.8 14 15 Our study used data from the SPRINT Primary Outcome Paper and included all participants with BP measurements in Year 02 with visits scheduled at months 15, 18, 21 and 24. The second year was chosen since it represented the time at which medication changes had stabilised and most participants remained in the study.
Randomisation and visit frequency: SPRINT participants were randomly assigned to open-label treatment groups with target SBP 135–139 (standard treatment, SPRINT-S) or target SBP<120 mm Hg (intensive treatment, SPRINT-I).8 14 Following a baseline visit, subsequent visits occurred monthly for 3 months then quarterly thereafter.
BP (mm Hg) was measured in SPRINT using an automated device (OMRON HEM-907 XL, Lake Forest, lllinois, USA) with subjects in a seated position after 5 min rest. Three measurements were taken with the visit mean value available for analysis.14
The SPRINT treatment protocol included monthly medication adjustments for participants in the intensive treatment group until target SBP<120 was achieved. The standard treatment group had medications adjusted to target SBP 135–139, with medications reduced if SBP was<130 on a single visit or<135 on two consecutive visits.14
Study duration: SPRINT was planned for 4–6 years duration but terminated after median follow-up of 3.3 years when interim analysis showed benefit in the primary outcome.8
The AMA MAP Hypertension (hereafter MAP) quality improvement programme was described.16 Clinicians at five healthcare organisations that agreed to participate in the MAP quality improvement programme were eligible for inclusion if their patient panel included≥24 adult patients with hypertension over the study period. The healthcare organisations were diverse, including two federally qualified health centres, two community-based health systems and one academic health centre.
The 2-year study period from 1 November 2019 through 31 October 2021 for this analysis reflected baseline data for two-thirds of patients before implementing MAP, that is, usual care. Staff at the two federally qualified health centres, which provided care for one-third of patients at MAP sites, received training in BP measurement described below.
Each clinician’s panel was comprised of adults≥18 years with a diagnosis of hypertension and at least two primary care visits with recorded BP in the 2-year study period. Anonymised participant-level data obtained from the electronic health records of participating institutions included demographic characteristics, height, weight, BP values, medications and comorbid conditions as described.16
BP measurements in MAP: BP was measured and recorded according to usual clinical processes at each participating health system. The credentials of the individuals measuring and recording BP were not available in the electronic record. MAP training, which occurred at the two federally qualified health centres, included instruction in patient positioning and arm cuff size.18 BP values≥140 systolic or≥90 diastolic at these two health centres led to a recommendation for automated office BP in triplicate on subjects in the seated position without additional rest. The mean of the three values was recorded. Repeat BP values after an initially elevated BP were obtained in 40–80% of adults at the federally qualified health centres. For all health systems in this study, when two or more BP values were entered for an encounter, the entry with the lowest SBP value defined BP for that encounter.
Data analysis
Statistical methods focused on the distribution of BP values and relationships to hypertension control at<140/<90 in the SPRINT and MAP databases. The primary outcome in SPRINT was patient-level BP control in the standard and intensive treatment cohorts. In MAP, the primary outcome was patient-level control to<140/<90 as a function of their clinicians’ mSBP (mm Hg) in 5 mm Hg increments. In MAP, BP control to SBP<140, SBP<130 and BP<130/<80 was also assessed as a function of their clinicians’ mSBP or the best of last visit mSBP or mSBP for all study visits.
As secondary outcomes, the percentage of study visits controlled to<140/<90 was also assessed as a function of the participants’ mSBP in 5 mm Hg increments from all study visits in (1) Year 2 in the two arms of SPRINT and (2) during the 2-year study period in MAP.
Using only MAP data, multiple linear regression was used to model clinician-level hypertension control as a function of their patient panel mSBP at the patient’s last visit to different SBP/DBP control thresholds (<140/<90, <130/<80) and SBP thresholds (<140, <130). The multivariable regression analysis was performed with mSBP and mean values for DBP as well as SBP and DBP variability (SD). Model fit was assessed using R2. SAS V.9.4 (SAS Institute, Cary, North Carolina, USA) and R V.4.0 were used for all analyses.
Results were disaggregated by age, race and sex. Mean BP values on first and last visit and the mean across all visits, as well as categories of control status at BP<140/<90 and BP<130/<80 were examined by: age group, defined as<60 years and≥60 years; race recorded as either black or white due to the limited number of patients identified in other race groups; sex as either female or male. Patients with missing data on these characteristics were excluded. The disaggregated analysis from MAP at the clinician level was restricted to clinicians having at least 16 patients in each of the subgroups. Among the 544 total clinicians, the number excluded by age, race and sex were 75, 150 and 83, respectively.
Results
The process for selecting SPRINT participants was described.8 14 Visits in SPRINT Year 2 occurred in 8626 participants (92% of original cohort). Among 4303 subjects in the SPRINT-S Year 2 cohort, 3665 (85%) were seen at all 4 visits and 4201 (98%) had two or more visits. Among 4323 subjects in the SPRINT-I Year 2 cohort, 3706 (86%) were seen at all 4 visits and 4200 (97%) had at least two visits.
The process for selecting MAP patients is depicted in figure 1. Of 348 729 adults≥18 years seen during the 2-year study period, 187 978 had a hypertension diagnosis. Excluding individuals having fewer than two encounters with BP measurement and individuals seen by clinicians having<24 adults with hypertension resulted in 169 978 study patients. This patient group had 911 180 encounters with BP values. All patients had at least two visits, 58 683 patients (34%) had two to three visits and 111 295 patients (66%) had four or more visits.
Figure 1. The process is depicted for selecting the 169 978 patients with hypertension for analysis from the MAP BP database. BP, blood pressure; MAP, Measure Accurately, Act Rapidly, Partner with patients.
Descriptive characteristics of adults in SPRINT-S and SPRINT-I and MAP are provided in table 1. SPRINT participants were older than MAP participants, whereas MAP participants had higher body mass index. In MAP, BP was controlled to<140/<90 for 62% of adults on their first visit and 70% on their last visit during the 2-year study period. BP values and control rates were similar in SPRINT-S and MAP participants at the first visit and across all visits. BP control improved over the study period in MAP but declined slightly in SPRINT-S and SPRINT-I. Racial differences in BP values were smaller in SPRINT than MAP, although BP control among black adults in MAP was higher than in SPRINT-S at the last study visit.
Table 1. Selected patient characteristics, BP values and hypertension control in two databases.
| SPRINT POP year 2 | AMA MAPBP2019–2021 | ||
| Group | Standard | Intensive | |
| Number | 4303 | 4323 | 169 978 |
| Age, years* | 67.8±9.5 | 67.9±9.4 | 60.4±13.8 |
| Female, n (%)† | 1486 (34.5) | 1527 (35.3) | 95 715 (56.3) |
| Male, n (%) | 2817 (65.5) | 2796 (64.7) | 74 260 (43.7) |
| White, n (%)‡ | 2502 (58.2) | 2517 (58.2) | 95 445 (56.2) |
| Black, n (%) | 1298 (30.2) | 1258 (29.1) | 64 450 (37.9) |
| Asian, n (%) | -- | -- | 2688 (1.6) |
| Other, n (%)† | 503 (11.7) | 548 (12.7) | 5529 (3.3) |
| BMI, kg/m2 | 29.8±5.7 | 30.0±5.8 | 32.1±7.8 |
| Diabetes mellitus, n (%)§ | 0 | 0 | 62 188 (36.6) |
| SBP, mm Hg | |||
| First visit | 134.9±13.0 | 120.7±13.3 | 134.8±18.2 |
| Last visit | 136.7±13.3 | 121.7±14.3 | 132.1±16.5 |
| Average all visits | 135.5±8.8 | 120.9±10.0 | 133.5±13.1 |
| DBP, mm Hg | |||
| First visit | 75.0±11.4 | 67.7±10.4 | 79.0±11.6 |
| Last visit | 76.1±10.9 | 68.2±10.3 | 77.2±10.5 |
| Average all visits | 75.3±9.7 | 67.7±8.8 | 78.1±8.6 |
| BP control first visit | |||
| <140/<90, n (%) | 2868 (66.7) | 3919 (90.7) | 104 519 (61.5) |
| <130/<80, n (%) | 1138 (26.5) | 3230 (74.7) | 46 179 (27.2) |
| BP control last visit | |||
| <140/<90, n (%) | 2611 (60.7) | 3822 (88.4) | 118 593 (69.8) |
| <130/<80, n (%) | 912 (21.2) | 3063 (70.9) | 53 886 (31.7) |
| BP control average all visits | |||
| <140/<90, n (%) | 3048 (70.8) | 4081 (94.4) | 121 193 (71.3) |
| <130/<80, n (%) | 805 (18.7) | 3499 (80.9) | 53 344 (31.4) |
Age was top coded at 90 years in SPRINT.
Missing values for sex in AMA MAP, 3 (0.002%).
Other race in SPRINT included designations of other (standard arm, 65 and intensive arm, 87) and Hispanic (standard arm, 438 and intensive arm, 461). Missing values for race in AMA MAP, 1866 (1.1%).
Diabetes was an exclusion criterion in SPRINT.
AMAAmerican Medical AssociationBMIbody mass indexBPblood pressureDBPdiastolic blood pressureMAPMeasure Accurately, Act Rapidly, Partner with patientsSBPsystolic blood pressureSPRINT POPSystolic blood PRessure Intervention Trial Primary Outcome Paper
BP control rates are provided by age (<60, ≥60 years), race (black, white) and sex (male, female) in table 2. BP control was higher among older than younger subjects in SPRINT-S and MAP, but slightly higher in older than younger adults in SPRINT-I. In SPRINT-S, SPRINT-I and MAP, BP control was higher in white than black adults. BP control was higher in men than women in SPRINT, but higher in women than men in MAP. BP values for the age, race and sex groups in SPRINT and MAP are provided in online supplemental table S1.
Table 2. BP values and control rates in SPRINT and MAP by age, race and sex subgroups.
| A. Age | SPRINT POP year 2 | AMA MAP | ||||
| Age<60 | Age≥60 | Age<60 | Age≥60 | |||
| Standard | Intensive | Standard | Intensive | |||
| n | 886 | 905 | 3417 | 3418 | 78 065 | 91 913 |
| BP control first visit | ||||||
| <140/<90, n (%) | 563 (63.5) | 832 (91.9) | 2305 (67.5) | 3087 (90.3) | 45 517 (58.3) | 59 002 (64.2) |
| <130/<80, n (%) | 176 (19.9) | 643 (71.1) | 962 (28.2) | 2587 (75.7) | 17 726 (22.7) | 28 453 (31.0) |
| BP control last visit | ||||||
| <140/<90, n (%) | 546 (61.6) | 814 (89.9) | 2065 (60.4) | 3008 (88.0) | 53 660 (68.7) | 64 933 (70.6) |
| <130/<80, n (%) | 177 (20.0) | 627 (69.3) | 735 (21.5) | 2436 (71.3) | 21 640 (27.7) | 32 246 (35.1) |
| BP control all visits | ||||||
| <140/<90, n (%) | 602 (68.0) | 867 (95.8) | 2446 (71.6) | 3214 (94.0) | 54 537 (69.9) | 66 656 (72.5) |
| <130/<80, n (%) | 138 (15.6) | 702 (77.6) | 667 (19.5) | 2797 (81.8) | 20 285 (26.0) | 33 059 (36.0) |
| B. Race | SPRINT POP year 2 | AMA MAP | ||||
| Black | White | Black | White | |||
| Standard | Intensive | Standard | Intensive | |||
| n | 1298 | 1258 | 2502 | 2517 | 64 450 | 95 445 |
| BP control first visit | ||||||
| <140/<90, n (%) | 794 (61.2) | 1117 (88.8) | 1696 (67.8) | 2301 (91.4) | 34 770 (53.9) | 64 134 (67.2) |
| <130/<80, n (%) | 309 (23.8) | 881 (70.0) | 728 (29.1) | 1918 (76.2) | 14 166 (22.0) | 29 429 (30.8) |
| BP control last visit | ||||||
| <140/<90, n (%) | 773 (59.6) | 1091 (86.7) | 1485 (59.4) | 2233 (88.7) | 41 329 (64.1) | 70 761 (74.1) |
| <130/<80, n (%) | 267 (20.6) | 855 (68.0) | 549 (21.9) | 1797 (71.4) | 17 520 (27.2) | 33 473 (35.1) |
| BP control all visits | ||||||
| <140/<90, n (%) | 872 (67.2) | 1169 (92.9) | 1795 (71.7) | 2391 (95.0) | 40 542 (62.9) | 74 296 (77.8) |
| <130/<80, n (%) | 203 (15.6) | 959 (76.2) | 517 (20.7) | 2071 (82.3) | 15 184 (23.6) | 35 468 (37.2) |
| C. Sex | SPRINT POP year 2 | AMA MAP | ||||
| Male | Female | Male | Female | |||
| Standard | Intensive | Standard | Intensive | |||
| n | 2817 | 2796 | 1486 | 1527 | 74 260 | 95 715 |
| BP control first visit | ||||||
| <140/<90, n (%) | 1907 (67.7) | 2567 (91.8) | 961 (64.7) | 1352 (88.5) | 44 984 (60.5) | 59 534 (62.2) |
| <130/<80, n (%) | 741 (26.3) | 2122 (75.9) | 397 (26.7) | 1108 (72.6) | 19 507 (26.3) | 26 672 (27.9) |
| BP control last visit | ||||||
| <140/<90, n (%) | 1735 (61.6) | 2506 (89.6) | 876 (59.0) | 1316 (86.2) | 51 538 (69.4) | 67 053 (70.1) |
| <130/<80, n (%) | 610 (21.7) | 2030 (72.6) | 302 (20.3) | 1033 (67.7) | 23 107 (31.1) | 30 778 (32.2) |
| BP control all visits | ||||||
| <140/<90, n (%) | 2026 (71.9) | 2664 (95.3) | 1022 (68.8) | 1417 (92.8) | 52 486 (70.7) | 68 705 (71.8) |
| <130/<80, n (%) | 521 (18.5) | 2289 (81.9) | 284 (19.1) | 1210 (79.2) | 22 710 (30.6) | 30 634 (32.0) |
AMAAmerican Medical AssociationBPblood pressureMAPMeasure Accurately, Act Rapidly, Partner with patientsSPRINT POPSystolic blood PRessure Intervention Trial Primary Outcome Paper
Among 544 clinicians in MAP, 90% (490) had a mSBP between 120 and <140 based on their patients’ last SBP. Percentages of patients controlled to BP<140/<90 and SBP<140 (table 3) as well as SBP<130 and BP<130/80 (online supplemental table S2) all fell as clinician mSBP rose. Hypertension control rates were similar when using the patients’ last or mean SBP for the 2-year period (online supplemental table S3).19 Control rates were higher when using the best of the patient’s last or mSBP for all study visits (online supplemental table S4). Hypertension control rates to<140/<90 and <140 were more comparable than were control rates to<130/<80 and <130, since 96% of adults with SBP<140, also had DBP<90, while only 71% of adults with SBP<130 had DBP<80 (data not shown).
Table 3. Hypertension control to SBP<140 and BP<140/<90 for clinicians grouped by their patients’ mean SBP at the last visit.
| Clin meanPt last SBP | Clinician, N | Pt, N | Patient last SBP | SBP<140 | BP<140/<90 | |||
| Mean | SD | Pt, N | % | Pt, N | % | |||
| 120–125 | 8 | 3318 | 124 | 11.8 | 2978 | 89.80 | 2908 | 87.60 |
| 125–130 | 149 | 59 917 | 127.9 | 14.1 | 49 089 | 81.90 | 47 188 | 78.80 |
| 130–135 | 192 | 64 375 | 131.8 | 15.3 | 47 659 | 74.00 | 45 575 | 70.80 |
| 135–140 | 141 | 29 461 | 137.5 | 18.5 | 17 589 | 59.70 | 16 772 | 56.90 |
| 140–145 | 50 | 11 757 | 141.7 | 20.2 | 5951 | 50.60 | 5678 | 48.30 |
| 145–150 | 4 | 1150 | 147 | 23.4 | 476 | 41.40 | 472 | 41.00 |
BPblood pressurePtpatientSBPsystolic blood pressure
The percentages of patients controlled to<140/<90 at the last visit (figure 2, upper panel) were 88% among clinicians with mSBP 120 to <125 (similar to SPRINT-I), 79% with mSBP 125 to <130, 71% with mSBP 130 to <135 and 57% with mSBP 135 to <140 (similar to SPRINT-S). The relationship between clinician-level mSBP and control to<140/<90 was similar by age, race and sex subgroups (figure 2, lower panel).
Figure 2. Upper panel. The relationship is shown between clinician-level mSBP at their patients’ last visit in 5 mm Hg bands and for mSBP in SPRINT-S and SPRINT-I and patient-level control rates to<140/<90 mm Hg on the last visit in the study period. At comparable SBP bands, patient-level control rates are similar in MAP and SPRINT. Lower panel. The relationship between clinician-level mSBP in MAP and control to<140/<90 is shown for their patients by age, race and sex group. MAP, Measure Accurately, Act Rapidly, Partner with patients; mSBP, mean systolic blood pressure; SPRINT, Systolic blood PRessure Intervention Trial; SPRINT-I, intensive treatment SPRINT; SPRINT-S, standard treatment SPRINT.
In multivariable regression models with BP control at the clinician level as the dependent variable, mSBP accounted for 80% of variance (r2) in control to<140/<90 (figure 3, upper panel). Accounting for patient age, race and sex did not significantly alter the relationship of mSBP to control at<140/<90 (r2=0.81). Varying the definition of the dependent variable as control to SBP<140, <130/<80 and SBP<130, the variance explained was 87%, 43% and 85%, respectively (figure 3, lower panel). Adding DBP and SD of SBP and DBP to SBP increased variance explained in control to 86% (<140/<90), 89% (<140), 69% (<130/<80) and 87% (<130).
Figure 3. The relationship is shown between clinician-level mSBP and control of their respective patient panels to<140/<90, <140, <130/<80 and <130. Control rates to the various targets were inversely associated with mSBP. mSBP, mean systolic blood pressure.
The relationship between participant-level mSBP from all MAP and SPRINT study visits and the percentage of visits controlled to<140/<90 is shown in figure 4. The percentage of visits with BP controlled to<140/<90 declined as participant level mSBP increased.
Figure 4. The inverse relationship between participant-level mSBP in 5 mm Hg increments across all study visits and the percentage of visits with BP controlled to<140/<90 were similar for SPRINT-S, SPRINT-I and MAP. MAP, Measure Accurately, Act Rapidly, Partner with patients; mSBP, mean systolic blood pressure; SPRINT, Systolic blood PRessure Intervention Trial; Sint, intensive treatment SPRINT; Sstd, standard treatment SPRINT.
Discussion
Our study showed the degree to which mSBP (mm Hg) was associated with BP control to<140/<90. This relationship was remarkably similar between clinical trial and real-world participants as well as by age, race and sex, which suggests a broadly generalisable finding. mSBP<130 was required for clinicians to control 80% or more of their patients to<140/<90 and for patients to be controlled to<140/<90 on ≥80% of encounters. Also, mSBP achieved by clinicians in MAP at their patients’ last visits accounted for 80% of variance between clinicians in their patients achieved control rate to<140/<90, confirming the importance of target mSBP for clinical practice.
A study strength is the inclusion of adults from a rigorous clinical trial and from diverse, real-world, primary care sites.8 15 Although the inclusion of data from the less controlled primary care setting could be viewed as a limitation in some respects, it provides real-world confirmation of clinical trial data. At comparable SBP values, hypertension control was similar in SPRINT and MAP, despite differences in BP measurement between a rigorously designed clinical trial and a real-world study. Participants in the two arms of SPRINT and in MAP also had similar percentages of study visits controlled to<140/<90 when grouped by comparable participant-level mSBP across all study visits. Generalisability of our main finding is also supported by similar control rates across age, race and sex groups at each 5 mm Hg band of clinician-level mSBP.
Very few prior studies assessed the relationship between mSBP and hypertension control. In SPRINT, SBP at various points in time was associated with corresponding changes in percentages of participants at goal.20 The authors reported few predictors of SBP control in multivariate analysis but did not include mSBP in the model. We reported that mSBP among adults with treated hypertension at different time points in a nationally representative sample was inversely associated with hypertension control.12 Based on plausible values for the SD of SBP, we estimated that mSBP 120–124 was required to control hypertension to<140/<90 in 88% of adults with treated hypertension, the implied control rate in Healthy People 2020.21 In the Intersalt study,22 mSBP correlated strongly with the prevalence of SBP values≥140 (r=0.85) in adults 20–59 years across 52 centres from 32 countries.23 Thus, mSBP predicts prevalent hypertension in a general population and BP control in adults with hypertension. We reported that control of SBP to<140 from 1999 to 2012 in the USA increased as mSBP decreased,24 suggesting that the relationship between mSBP and BP control persists over time.
Our findings have important implications for key stakeholders aiming to optimise hypertension control and prevent major adverse cardiovascular events and deaths. Many patients and patient groups will require a≥10 mm Hg or greater reduction in mSBP to attain high and consistent control to<140/<90. There are three main options for reducing mSBP≥10 mm Hg. Intensification of antihypertensive therapy, lifestyle changes and a combination of the two. In the absence of meaningful lifestyle change or test-guided prescribing strategies, many patients will require an additional medication class at standard dose,5,9 since doubling the dose of a single antihypertensive medication class typically lowers SBP by 2–3 mm Hg.9 Low-to-moderate doses of two or more antihypertensive medications in single-pill combinations are an efficient strategy with the potential for improving patient adherence, BP control and cardiovascular outcomes.5,725 Lifestyle changes, especially in combination, including greater intake of whole foods, reduced intake of salt and highly processed foods as well as weight loss, and aerobic, resistance and isometric exercise can reduce mSBP≥10 mm Hg but are often difficult to initiate and sustain.5,7 If clinicians and their patients understand that mSBP in the 120–129 range leads to fewer cardiovascular events than higher mSBP values,28,31 then this may translate into greater acceptance of the lifestyle changes and therapeutic intensification required to attain mSBP<130. In the process, better hypertension control and cardiovascular health can be achieved.
Limitations
First, baseline BP values in MAP were obtained prior to training using a standard protocol and recommended measuring devices.18 MAP includes training in BP measurement and recommends remeasuring uncontrolled readings with validated devices for automated office BP.16 However, health systems are not required to have validated devices for automated office BP to participate in MAP. Second, despite the diversity of health systems and patients participating in MAP, these sites may not fully reflect the diversity seen nationally and internationally. Third, 2 years rather than 1 year of MAP data were included in the analysis to increase sample size. Fourth, SPRINT excluded many individuals with hypertension who are prevalent in primary care, including adults with diabetes mellitus and those with severe or treatment-resistant hypertension.15 Fifth, MAP did not assess treatment-related serious adverse event rates at different levels of achieved mSBP; however, SPRINT showed that intensive SBP treatment did not lead to a higher overall rate of serious adverse events than standard treatment.8
Conclusions
Mean SBP>10 mm Hg lower than target BP threshold is required to reliably achieve acceptable BP control rates of≥80% and higher to<140/<90 mm Hg for groups of adults with hypertension, as well as control on ≥80% of medical encounters for individual patients with hypertension. Moreover, mean SBP in the 120–129, which is required to achieve high and consistent control to<140/<90, is associated with fewer cardiovascular events than higher mSBP levels.28,31 A mSBP in the 120–129 range will also mean numerous BP values<120 mm Hg, with increasing evidence that this is safe and effective.31
supplementary material
This manuscript was prepared using Systolic blood PRessure Intervention Trial (SPRINT) research materials obtained from the National Heart, Lung and Blood Institute (NHLBI) Biologic Specimen and Data Repository Information Coordinating Center and does not necessarily reflect the opinions or views of the SPRINT or the NHLBI. The comments and conclusions in this paper are those of the authors and do not necessarily represent the views of the American Medical Association.
Footnotes
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Prepub: Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2024-090440).
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Not applicable.
Ethics approval: The University of Illinois at Chicago's Institutional Review Board (IRB), the local review board for the American Medical Association (AMA), confirmed this study met criteria for exemption from informed consent (Protocol 2022-0782).
Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Data availability free text: Systolic blood PRessure Intervention Trial data are available through an application process from the Biologic Specimen and Data Repository Information Coordinating Center (BioLINCC), managed by the National Heart, Lung and Blood Institute (NHLBI) (https://biolincc.nhlbi.nih.gov). MAP data are restricted by legal agreement with participating health systems and are not available. Selected statistical code may be requested (susan.sutherland @ama-assn.org).
Data availability statement
Data are available upon reasonable request.
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