Trends in end digit preference for blood pressure and associations with cardiovascular outcomes in Canadian and UK primary care: a retrospective observational study

Improving cardiovascular control in a hypertensive population in primary care. Results from a staff training intervention

OBJECTIVE

A pilot study to evaluate a staff training intervention implementing a nurse-led hypertension care model.

DESIGN AND SETTING

Clinical and laboratory data from all primary care centres (PCCs) in the Swedish region Västra Götaland (VGR), retrieved from regional registers. Intervention started 2018 in 11 PCCs. A total of 190 PCCs served as controls. Change from baseline was assessed 2 years after start of intervention.

INTERVENTION

Training of selected personnel, primarily in drug choice, team-based care, measurement techniques, and use of standardized medical treatment protocols.

PATIENTS

Hypertensive patients without diabetes or ischemic heart disease were included. The intervention and control groups contained approximately 10,000 and 145,000 individuals, respectively.

MAIN OUTCOME MEASURES

Blood pressure (BP) <140/90 mmHg, LDL-cholesterol (LDL-C) <3.0 mmol/L, BP ending on -0 mmHg (digit preference, an indirect sign of manual measuring technique), choice of antihypertensive drugs, cholesterol lowering therapy and attendance patterns were measured.

RESULTS

In the intervention group, the percentage of patients reaching the BP target did not change significantly, 56%-61% (control 50%-52%), non-significant. However, the percentage of patients with LDL-C < 3.0 mmol/L increased from 34%-40% (control 36%-36%), p = .043, and digit preference decreased, 39%-27% (control 41%-35%), p = 0.000. The number of antihypertensive drugs was constant, 1.63 - 1.64 (control 1.62 - 1.62), non-significant, but drug choice changed in line with recommendations.

CONCLUSION

Although this primary care intervention based on staff training failed to improve BP control, it resulted in improved cardiovascular control by improved cholesterol lowering treatment.

Assessing Primary Care Blood Pressure Documentation for Hypertension Management During the COVID-19 Pandemic by Patient and Provider Groups

Background

Primary care electronic medical record (EMR) data can be used to identify, manage, and screen hypertension cases. However, this approach relies on completeness and accessibility of documented blood pressure (BP) values. With the large switch to virtual care due to the COVID-19 pandemic, we assessed BP documentation in primary care EMRs during the pandemic, across patient and physician groups.

Methods

Hypertension-related visits were identified during the pre-pandemic (January 2017 to February 2020) and pandemic (March 2020 to December 2021) periods from a primary care EMR database in Ontario, Canada. Clustered logistic regression models were used to analyze the relationship of physician and patient characteristics with an outcome variable of documented BP. A chart review of 3200 hypertension visits without a BP recorded in structured data fields was conducted to determine if BP was recorded in progress notes.

Results

Pre-pandemic, 75.7% of hypertension-related visits (113,966 of 150,511) had a BP recorded in structured documentation, but this significantly decreased to 36.4% (26,660 of 73,239) during the pandemic (odds ratio [OR] = 0.18, 95% confidence interval [CI]: 0.18-0.19). For virtual visits, 14.3% (6357 of 44,572) had a documented BP, vs 74.0% (20,056 of 27,089) for in-person visits. Chart review found that 55.9% of hypertension visits had no associated BP in structured documentation, but did have a BP recorded in the progress note. Male providers, compared to female providers, were less likely to record BPs pre-pandemic (OR = 0.45, 95% CI: 0.32-0.63) and during the pandemic, for both virtual visits (OR = 0.48, 95% CI: 0.32-0.71) and in-person visits (OR = 0.46, 95% CI: 0.33-0.64).

Conclusions

BP documented in primary care EMRs declined during the pandemic, most likely due to high rates of virtual visits impacting hypertension detection and management.

Digit preference and biased conclusions in cardiac arrest studies

BACKGROUND

In cardiac arrest (CA), time is directly predictive of patients' prognosis. The increase in mortality resulting from delayed cardiopulmonary resuscitation has been quantified minute by minute. Times reported in CA management studies could reflect a timestamping bias referred to as "digit preference". This phenomenon leads to a preference for certain numerical values (such as 2, 5, or 10) over others (such as 13). Our objective was to investigate whether or not digit preference phenomenon could be observed in reported times of the day related to CA management, as noted in a national registry.

METHODS

We analyzed data from the French National Electronic Registry of Cardiac Arrests. We analyzed twelve times-of-the-day corresponding to each of the main steps of CA management reported by the emergency physicians who managed the patients in prehospital settings. We postulated that if CA occurred at random times throughout the day, then we could expect to see events related to CA management occurring at a similar rate each minute of each hour of the day, at a fraction of 1/60. We compared the fraction of times reported as multiples of 15 (0, 15, 30, and 45 - on the hour, quarters, half hour) with the expected fraction of 4/60 (i.e. 4 × 1/60).

MAIN RESULTS

A total of 47,211 times-of-the-day in relation to 6131 CA were analyzed. The most overrepresented numbers were: 0, with 3737 occurrences (8% vs 2% expected, p < 0.0001) and 30, with 2807 occurrences (6% vs 2% expected, p < 0.0001). Times-of-the-day as multiples of 15 were overrepresented (22% vs 7% expected, p < 0.0001).

CONCLUSION

Prospectively collected times were considerably influenced by digit preference phenomenon. Studies that are not based on automatic time recordings and that have not evaluated and considered this bias should be interpretated with caution.

Prevalence of Hypertension among Children Based on the New American Academy of Pediatrics Clinical Practice Guidelines

Background

In 2017, the American Academy of Pediatrics (AAP) updated clinical practice guidelines for the diagnosis and management of hypertension in children. The present study aimed to assess the prevalence of hypertension in Iranian children based on the latest guidelines.

Methods

Data on 7301 student participants (3589 boys and 3712 girls) aged between 7-12 yr were assessed. The data were extracted from the fifth Childhood and Adolescence Surveillance and Prevention of Adult Non-communicable Disease (CASPIAN V) school-based study conducted in the 30 provinces of Iran in 2015. Blood pressure (BP) was classified as normal, elevated BP, and stage 1 and 2 hypertension using weighted analysis and the 2017 AAP guidelines. All analyses were performed in STATA 14.0 statistical software, with findings presented in terms of prevalence.

Results

The overall prevalence of high BP in Iranian children was 14.7%. In addition, 15.1% of boys had high BP, with 9.4% and 1.7% of them with stage 1 and 2 hypertension, respectively. Moreover, 14.3% of girls had high BP, of which 10% had stage 1 and 1.3% with stage 2 hypertension. For elevated hypertension, it was observed in 4% of boys and 3% of girls.

Conclusion

Using the 2017 AAP guidelines demonstrated a higher prevalence of hypertension in children (14.7%) in Iran. The prevalence of hypertension in boys was slightly higher compared to girls.

Family doctor responses to changes in target stringency under financial incentives

Healthcare providers may game when faced with targets. We examine how family doctors responded to a temporary but substantial increase in the stringency of targets determining payments for controlling blood pressure amongst younger hypertensive patients. We apply difference-in-differences and bunching techniques to data from electronic health records of 107,148 individuals. Doctors did not alter the volume or composition of lists of their hypertension patients. They did increase treatment intensity, including a 1.2 percentage point increase in prescribing antihypertensive medicines. They also undertook more blood pressure measurements. Multiple testing increased by 1.9 percentage points overall and by 8.8 percentage points when first readings failed more stringent target. Exemption of patients from reported performance increased by 0.8 percentage points. Moreover, the proportion of patients recorded as exactly achieving the more stringent target increased by 3.1 percentage points to 16.6%. Family doctors responded as intended and gamed when set more stringent pay-for-performance targets.

Association of an Automated Blood Pressure Measurement Quality Improvement Program With Terminal Digit Preference and Recorded Mean Blood Pressure in 11 Clinics

IMPORTANCE

Terminal digit preference has been shown to be associated with inaccurate blood pressure (BP) recording.

OBJECTIVE

To evaluate whether converting from manual BP measurement with aneroid sphygmomanometers to automated BP measurement was associated with terminal digit preference, mean levels of recorded BP, and the rate at which hypertension was diagnosed.

DESIGN, SETTING, AND PARTICIPANTS

This quality improvement study was conducted from May 9, 2021, to March 24, 2022, using interrupted time series analysis of medical record data from 11 primary care clinics in a single health care system from April 2008 to April 2015. The study population was patients aged 18 to 75 years who had their BP measured and recorded at least once during the study period.

EXPOSURES

Manual BP measurement before April 2012 vs automated BP measurement with the Omron HEM-907XL monitor from May 2012 to April 2015.

MAIN OUTCOMES AND MEASURES

The main outcome was the distribution of terminal digits and mean systolic BP (SBP) values obtained during 4 years of manual measurement vs 3 years of automated measurement, assessed using a generalized linear mixed regression model with a random intercept for clinic and adjusted for seasonal fluctuations and patient demographic and clinical characteristics.

RESULTS

The study included 1 541 227 BP measurements from 225 504 unique patients during the entire study period, with 849 978 BP measurements from 165 137 patients (mean [SD] age, 47.1 [15.2] years; 58.2% female) during the manual measurement period and 691 249 measurements from 149 080 patients (mean [SD] age, 48.4 [15.3] years; 56.3% female) during the automated measurement period. With manual measurement, 32.8% of SBP terminal digits were 0 (20% was the expected value because nursing staff was instructed to record BP to the nearest even digit). This proportion decreased to 12.4% during the automated measurement period (expected value, 10%) when both even and odd digits were to be recorded. After automated measurement was implemented, the mean SBP estimated with statistical modeling increased by 5.09 mm Hg (95% CI, 4.98-5.19 mm Hg). Fewer BP values recorded during the automated than the manual measurement period were below 140/90 mm Hg (69.9% vs 84.3%; difference, -14.5%; 95% CI, -14.6% to -14.3%) and below 130/80 mm Hg (42.1% vs 60.0%; difference, -17.9%; 95% CI, -18.0% to -17.7%). The proportion of patients with a diagnosis of hypertension was 4.3 percentage points higher (23.4% vs 19.1%) during the automated measurement period.

CONCLUSIONS AND RELEVANCE

In this quality improvement study, automated BP measurement was associated with decreased terminal digit preference and significantly higher mean BP levels. The method of BP measurement was also associated with the rate at which hypertension was diagnosed. These findings may have implications for pay-for-performance programs, which may create an incentive to record BP levels that meet a particular goal and a disincentive to adopt automated measurement of BP.

Refining determinants of associations of visit-to-visit blood pressure variability with cardiovascular risk: results from the Action to Control Cardiovascular Risk in Diabetes Trial

OBJECTIVES

As there is uncertainty about the extent to which baseline blood pressure level or cardiovascular risk modifies the relationship between blood pressure variability (BPv) and cardiovascular disease, we comprehensively examined the role of BPv in cardiovascular disease risk in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Trial.

METHODS

Using data from ACCORD, we examined the relationship of BPv with development of the primary CVD outcome, major coronary heart disease (CHD), and total stroke using time-dependent Cox proportional hazards models.

RESULTS

BPv was associated with the primary CVD outcome and major CHD but not stroke. The positive association with the primary CVD outcome and major CHD was more pronounced in low and high strata of baseline SBP (<120 and >140 mmHg) and DBP (<70 and >80 mmHg). The effect of BPv on CVD and CHD was more pronounced in those with both prior CVD history and low blood pressure. Dips, not elevations, in blood pressure appeared to drive these associations. The relationships were generally not attenuated by adjustment for mean blood pressure, medication adherence, or baseline comorbidities. A sensitivity analysis using CVD events from the long-term posttrial follow-up (ACCORDION) was consistent with the results from ACCORD.

CONCLUSION

In ACCORD, the effect of BPv on adverse cardiovascular (but not cerebrovascular) outcomes is modified by baseline blood pressure and prior CVD. Recognizing these more nuanced relationships may help improve risk stratification and blood pressure management decisions as well as provide insight into potential underlying mechanisms.

Digit Preference in Office Blood Pressure Measurements, United States 2015-2019

BACKGROUND

Blood pressure (BP) measurement error may lead to under- or overtreatment of hypertension. One common source of error is terminal digit preference, most often a terminal digit of "0." The objective was to evaluate national trends in terminal digit preference in office BP measurements among adults with treated hypertension.

METHODS

Data were from IQVIA's National Disease and Therapeutic Index, a nationally representative, serial cross-sectional survey of office-based physicians. The analysis included office visits from 2015 to 2019 among adults aged ≥18 years receiving antihypertensive treatment. Annual trends were examined in the percent of systolic and diastolic BP measurements ending in zero by patient sex, age, and race/ethnicity, physician specialty, and first or subsequent hypertension treatment visit.

RESULTS

From 2015 to 2019, there were ~60 million hypertension treatment visits annually (unweighted N: 5,585-9,085). There was a decrease in the percent of visits with systolic (41.7%-37.7%) or diastolic (42.7%-37.8%) BP recordings ending in zero. Trends were similar by patient characteristics. However, a greater proportion of measurements ended in zero among patients aged ≥80 (vs. 15-59 or 60-79) years, first (vs. subsequent) treatment visits, visits to cardiologists (vs. primary care physicians), and visits with systolic BP ≥140 or diastolic BP ≥90 (vs. <140/90) mm Hg.

CONCLUSIONS

Despite modest improvement, terminal digit preference remains a common problem in office BP measurement in the United States. Without bias, 10%-20% of measurements are expected to end in zero. Reducing digit preference is a priority for improving BP measurement accuracy and hypertension management.

Examining the effectiveness of telemonitoring with routinely acquired blood pressure data in primary care: challenges in the statistical analysis

Background

Scale-up BP was a quasi-experimental implementation study, following a successful randomised controlled trial of the roll-out of telemonitoring in primary care across Lothian, Scotland. Our primary objective was to assess the effect of telemonitoring on blood pressure (BP) control using routinely collected data. Telemonitored systolic and diastolic BP were compared with surgery BP measurements from patients not using telemonitoring (comparator patients). The statistical analysis and interpretation of findings was challenging due to the broad range of biases potentially influencing the results, including differences in the frequency of readings, ‘white coat effect’, end digit preference, and missing data.

Methods

Four different statistical methods were employed in order to minimise the impact of these biases on the comparison between telemonitoring and comparator groups. These methods were “standardisation with stratification”, “standardisation with matching”, “regression adjustment for propensity score” and “random coefficient modelling”. The first three methods standardised the groups so that all participants provided exactly two measurements at baseline and 6–12 months follow-up prior to analysis. The fourth analysis used linear mixed modelling based on all available data.

Results

The standardisation with stratification analysis showed a significantly lower systolic BP in telemonitoring patients at 6–12 months follow-up (-4.06, 95% CI -6.30 to -1.82, p < 0.001) for patients with systolic BP below 135 at baseline. For the standardisation with matching and regression adjustment for propensity score analyses, systolic BP was significantly lower overall (− 5.96, 95% CI -8.36 to − 3.55 , p < 0.001) and (− 3.73, 95% CI− 5.34 to − 2.13, p < 0.001) respectively, even after assuming that − 5 of the difference was due to ‘white coat effect’. For the random coefficient modelling, the improvement in systolic BP was estimated to be -3.37 (95% CI -5.41 to -1.33 , p < 0.001) after 1 year.

Conclusions

The four analyses provide additional evidence for the effectiveness of telemonitoring in controlling BP in routine primary care. The random coefficient analysis is particularly recommended due to its ability to utilise all available data. However, adjusting for the complex array of biases was difficult. Researchers should appreciate the potential for bias in implementation studies and seek to acquire a detailed understanding of the study context in order to design appropriate analytical approaches.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01219-8.

Temperature-adjusted hypertension prevalence and control rate: a series of cross-sectional studies in Guangdong Province, China

BACKGROUND

Previous studies have shown negative relationships between ambient temperature and blood pressure (BP). However, few studies estimated temperature-adjusted hypertension prevalence and control rate in different population.

OBJECTIVE

To estimate the effects of temperature on BP, and further calculate temperature-adjusted hypertension prevalence and control rate.

METHODS

Meteorological and BP data in Guangdong Province from 2004 to 2015 were collected. There were 31 351 participants aged 18 years and over. Based on 2018 European society Arterial Hypertension Guidelines, participants were divided into normotensive patients (n = 23 046), known hypertensive patients (n = 2807), and newly detected hypertensive patients (n = 5498). We first used generalized additive model to establish the nonlinear relationship between daily mean temperature and BP, and then calculated the linear effects of temperature on BP among populations with different hypertension status. Finally, we calculated the temperature-adjusted hypertension prevalence and control rate.

RESULTS

Generally, there is an inverse relationship between temperature and BP. For a 1 °C increase in temperature, the decreased SBPs for normotensive patients, newly detected hypertensive patients, and known hypertensive patients were 0.37 [95% confidence interval (CI): -0.40, -0.33] mmHg, 0.21 (95% CI: -0.32, -0.10) mmHg and 0.81 (95% CI: -1.02, -0.59) mmHg, while reduced DBPs were 0.19 (95% CI: -0.21, -0.16) mmHg, 0.01 (95% CI: -0.06,0.08) mmHg, and 0.44 (95% CI: -0.56, -0.32) mmHg, respectively. At 5, 10, 15, 20, and 25 °C, the hypertension prevalence rates were 32.5, 29.7, 27.7, 26.0, and 25.0%, respectively, and the control rates were 12.0, 17.5, 23.5, 30.1, and 37.1%, respectively.

CONCLUSION

Low temperature increased BP for all populations, especially for known hypertensive patients, which makes hypertension prevalence increase and control rate decrease if temperature reduce. Our findings suggest that temperature should be considered in hypertension clinic management and epidemiological survey.

Telemonitoring at scale for hypertension in primary care: An implementation study

BACKGROUND

While evidence from randomised controlled trials shows that telemonitoring for hypertension is associated with improved blood pressure (BP) control, healthcare systems have been slow to implement it, partly because of inadequate integration with existing clinical practices and electronic records. Neither is it clear if trial findings will be replicated in routine clinical practice at scale. We aimed to explore the feasibility and impact of implementing an integrated telemonitoring system for hypertension into routine primary care.

METHODS AND FINDINGS

This was a quasi-experimental implementation study with embedded qualitative process evaluation set in primary care in Lothian, Scotland. We described the overall uptake of telemonitoring and uptake in a subgroup of representative practices, used routinely acquired data for a records-based controlled before-and-after study, and collected qualitative data from staff and patient interviews and practice observation. The main outcome measures were intervention uptake, change in BP, change in clinician appointment use, and participants' views on features that facilitated or impeded uptake of the intervention. Seventy-five primary care practices enrolled 3,200 patients with established hypertension. In an evaluation subgroup of 8 practices (905 patients of whom 427 [47%] were female and with median age of 64 years [IQR 56-70, range 22-89] and median Scottish Index of Multiple Deprivation 2012 decile of 8 [IQR 6-10]), mean systolic BP fell by 6.55 mm Hg (SD 15.17), and mean diastolic BP by 4.23 mm Hg (SD 8.68). Compared with the previous year, participating patients made 19% fewer face-to-face appointments, compared with 11% fewer in patients with hypertension who were not telemonitoring. Total consultation time for participants fell by 15.4 minutes (SD 68.4), compared with 5.5 minutes (SD 84.4) in non-telemonitored patients. The convenience of remote collection of BP readings and integration of these readings into routine clinical care was crucial to the success of the implementation. Limitations include the fact that practices and patient participants were self-selected, and younger and more affluent than non-participating patients, and the possibility that regression to the mean may have contributed to the reduction in BP. Routinely acquired data are limited in terms of completeness and accuracy.

CONCLUSIONS

Telemonitoring for hypertension can be implemented into routine primary care at scale with little impact on clinician workload and results in reductions in BP similar to those in large UK trials. Integrating the telemonitoring readings into routine data handling was crucial to the success of this initiative.

Achieving quality primary care data: a description of the Canadian Primary Care Sentinel Surveillance Network data capture, extraction, and processing in Alberta

Introduction

Electronic medical record (EMR) databases have become increasingly popular for secondary purposes, such as health research. The Canadian Primary Care Sentinel Surveillance Network (CPCSSN) is the first and only pan-Canadian primary care EMR data repository, with de-identified health information for almost two million Canadians. Comprehensive and freely available documentation describing the data ‘lifecycle’ is important for assessing potential data quality issues and appropriate interpretation of research findings. Here, we describe the flow and transformation of CPCSSN data in the province of Alberta.

Approach

In Alberta, the data originate from 54 publicly-funded primary care settings, including one community pediatric clinic, with 318 providers contributing de-identified EMR data for 410,951 patients (as of December 2018). Data extraction methods have been developed for five different EMR systems, and include both backend and automated frontend extractions. The raw EMR data are transformed according to specific rules, including trimming implausible values, converting values and free text to standard terminologies or classification systems, and structuring the data into a common CPCSSN format. Following local data extraction and processing, the data are transferred to a central repository and made available for research and disease surveillance.

Conclusion

This paper aims to provide important contextual information to future CPCSSN data users.