Cardiovascular risk stratification in primary care patients with arterial hypertension: Results from the Swiss Hypertension Cohort Study (HccH)

Abstract

Aims

Few data are available on cardiovascular risk stratification in primary care patients treated for arterial hypertension. This study aimed at evaluating the cardiovascular risk profile of hypertensive patients included into the Swiss Hypertension Cohort Study according to the 2013 European Society of Hypertension/European Society of Cardiology Guidelines.

Methods

The Swiss Hypertension Cohort Study is a prospective, observational study conducted by the Centre for Primary Health Care of the University of Basel from 2006 to 2013. Patients with a diagnosis of arterial hypertension (office blood pressure measurement ≥140/90 mmHg) were enrolled. Office blood pressure measurement, cardiovascular risk factors, subclinical organ damage, diabetes mellitus, and established cardiovascular and renal disease were recorded at baseline and at an annual interval during routine consultations by general practitioners in Switzerland.

Results

In total, 1003 patients were eligible for analysis (55.6% male, mean age: 64.0 ± 13.2 years). At baseline, 78.5% of patients presented with either more than three additional cardiovascular risk factors, diabetes mellitus or subclinical organ damage, while 44.4% of patients had a high or very high overall cardiovascular risk. Cardiovascular risk factors and information about diabetes mellitus, established cardiovascular disease and renal disease were recorded mostly completely, whereas substantial gaps were revealed regarding the assessment of subclinical organ damage.

Conclusion

The present findings demonstrate that the majority of primary care patients with arterial hypertension bear a substantial number of additional cardiovascular risk factors, subclinical and/or established organ damage. This emphasizes the need for continuous cardiovascular risk stratification and adequate treatment of arterial hypertension in Switzerland.

Keywords

Arterial hypertension cardiovascular risk stratification cohort study subclinical and established organ damage primary care

Introduction

Arterial hypertension is associated with increased morbidity and mortality.^1–3 The Global Burden of Disease Study 2010 identified high blood pressure (BP) as the leading cardiovascular risk factor worldwide, followed by tobacco smoking, alcohol and drug use, diets low in fruits and high in sodium, high body mass index (BMI), high fasting plasma glucose, physical inactivity and high total cholesterol.⁴ In Switzerland, 34.9% of the adult population had high BP in 2016.⁵ Both systolic and diastolic BP correlate with the risk of stroke and coronary heart disease.^2,6 Moreover, arterial hypertension plays a key role in the pathogenesis of heart failure, peripheral artery disease (PAD) and chronic kidney disease (CKD).^7–10 According to the World Health Organization, cardiovascular diseases account for approximately 17 million deaths per year, representing one-third of global mortality.¹¹ Moreover, in 2011 an estimated 80% of health care costs in Switzerland (SFr64.6bn) were related to non-communicable diseases with a total of SFr10.3bn linked to cardiovascular diseases.¹²

Besides the level of BP, the number of additional cardiovascular risk factors and the long-standing presence of diabetes mellitus, subclinical and established organ damage favour the development of cardiovascular diseases. The individual patient risk depends on the type and number of risk factors as well as on the extent of pathologic changes.¹³ Careful risk stratification helps in understanding patients’ risk profile and guiding targeted treatment decisions. To date, few data are available on cardiovascular risk assessment in primary care patients treated for arterial hypertension. Two previous studies identified a high percentage (43% and 60%) of hypertensive patients in primary care as having a high or very high cardiovascular risk and emphasized the importance of global comprehensive cardiovascular risk stratification.^14,15

Therefore, the aim of the present study was to evaluate the cardiovascular risk profile of hypertensive patients included into the Swiss Hypertension Cohort Study (HccH). Furthermore, the compliance of general practitioners (GPs) with the 2013 European Society of Hypertension/European Society of Cardiology (ESH/ESC) Guidelines, which were applicable when performing HccH, on cardiovascular risk stratification was assessed in order to identify potential gaps in the risk stratification process.

Methods

Study design and procedures

HccH is a prospective, observational study conducted from 2006 to 2013 by the Centre for Primary Health Care of the University of Basel, Switzerland. Eighty-seven GPs from 12 cantons of Switzerland (see Figure 1) enrolled a total number of 1003 patients and recorded data via an internet-based database. Data collection was done at baseline and annually thereafter during routine consultations. The study protocol was approved by the local ethics committee (Ethikkommission beider Basel (EKBB), ID: 52/05) and written informed consent was obtained from all patients prior to study entry.

Figure 1.

Map of the cantons of Switzerland. Cantons participating in the Swiss Hypertension Cohort Study are marked in grey.

Study patients

Adult men and women (age ≥18 years) with an established diagnosis of arterial hypertension were eligible for enrolment into HccH. Inclusion criteria were antihypertensive treatment and/or mean through-sitting office BP measurement (OBPM) ≥140/90 mmHg. Diagnosis relied on the judgment of the treating physician, and treatment could be pharmacological and/or non-pharmacological (lifestyle modifications).

BP measurement

OBPM was based on the values measured at baseline. For every patient, a minimum of two BP readings were obtained in sitting position after at least 5 min of rest using calibrated aneroid or mercury sphygmomanometers or validated automatic devices, depending on availability. For risk stratification, BP was graded according to the 2013 ESH/ESC Guidelines.¹³

Assessment of clinical data

GPs were requested to record demographic characteristics (age, sex, smoking history, weight, height and waist circumference) for each patient. Obesity was defined as BMI ≥30 kg/m², while abdominal obesity was defined as waist circumference ≥102 cm in men and ≥88 cm in women. Furthermore, information on lifestyle modifications, antihypertensive drug therapy and concomitant treatments were documented. A laboratory screening for lipid and plasma glucose levels was conducted. Dyslipidaemia was defined as total cholesterol >4.9 mmol/L (190 mg/dL), or low density lipoprotein > 3.0 mmol/L (115 mg/dL), or high density lipoprotein < 1.0 in men (40 mg/dL) and <1.2 mmol/L in women (46 mg/dL), or triglycerides >1.7 mmol/L (150 mg/dL). Diabetes mellitus was considered if fasting plasma glucose levels were ≥7.0 mmol/L (126 mg/dL) on two repeated measurements, HbA1c was >7% (53 mmol/mol), or post-load plasma glucose values were >11.0 mmol/L (198 mg/dL). Mild CKD (defined as glomerular filtration rate (GFR) of 30–60 ml/min per 1.73 m²), microalbuminuria (albumin–creatinine ratio ≥2.26 mg/mmol or urinary protein dipstick test ≥2++), as well as signs of left ventricular hypertrophy (LVH) in electrocardiogram (ECG) (Sokolow–Lyon Index (S_V1 + R_V5/V6 ≥ 3.5 mV) or Cornell Voltage Product (R_aVL + S_V3 + 6 (in women)) × QRS-duration >244 mV*ms) and/or echocardiography (left ventricular mass index >115 g/m² in men, >95 g/m² in women) were considered as subclinical organ damage.^13,16 Assessment of established cardiovascular and renal disease included coronary heart disease, stroke and transient ischaemic attack (TIA), myocardial infarction, congestive heart failure, PAD, and severe CKD with a GFR <30 ml/min per 1.73m².¹³

Cardiovascular risk stratification

Cardiovascular risk stratification was performed according to the 2013 ESH/ESC Guidelines taking into account all available individual patient data. Risk was categorized as low, moderate, high, or very high, corresponding to a 10-year risk for cardiovascular morbidity and mortality of <15%, 15–20%, 20–30%, or >30%, respectively.^17,18

Data collection and management

The database used in HccH was developed by the Centre for Primary Health Care in cooperation with GPs and hosted by IBM SPSS Switzerland. Data entry was done by GPs participating in HccH via a password protected website (www.spss.serv.ch/IHAM/CaseManager). Anonymized data collection was ensured by using individual patient codes known by only the treating GP. Complete patient datasets were transferred via a secured channel to the study centre.

Statistics

Statistical analysis was performed using SPSS Version 22 (IBM SPSS Statistics). Discrete variables were expressed as number and percentage, continuous variables as mean and standard deviation (SD). Normal distribution of data was evaluated with the Shapiro–Wilk test, Q–Q Plot, histogram, skew and kurtosis. Mean comparisons between sexes and age groups were performed using Student’s t test or one-way analysis of variance, respectively Mann–Whitney U test or Kruskal–Wallis test, where applicable. Categorical variables were compared using the chi-squared test. Results were considered as statistically significant when a p-value of less than 5% was attained.

Results

Patient characteristics

This cross-sectional study analysed baseline data from the 1003 patients enrolled into HccH. Patient characteristics are presented in Table 1. More than half of the patients (55.6%) were male and age ranged from 18 to 103 years (mean age 64.0 ± 13.2 years). A small proportion of patients (13.7%) were younger than 50 years, while 22.1% were older than 75 years. Women were significantly older than men (67.5 ± 13.2 years vs. 62.0 ± 12.7 years, p < 0.001). The majority of patients were of Caucasian ethnicity (98.2%), while 1.0% of patients were of Asian, 0.4% of Black African and 0.4% of other ethnicity.

Table 1.

Baseline characteristics of 1003 patients enrolled into the Swiss Hypertension Cohort Study.

Parameters	n (%)	Mean ± SD or n (%)
Demographic data
Age [years]	1003 (100)	64.0 ± 13.2
Male sex	1003 (100)	558 (55.6%)
Clinical features
OBPM SBP [mmHg]	1003 (100)	145 ± 17
OBPM DBP [mmHg]	1003 (100)	85 ± 11
HR_rest [beats/min]	1003 (100)	73.0 ± 10.7
BMI [kg/m²]	1003 (100)	28.0 ± 5.0
WC [cm]	82 (8.2)	102.1 ± 12.2
Laboratory values
Total cholesterol [mmol/L]	876 (87.3)	5.3 ± 1.1
HDL [mmol/L]	747 (74.5)	1.4 ± 0.4
LDL [mmol/L]	628 (62.6)	3.1 ± 1.0
Triglycerides [mmol/L]	792 (79.0)	1.8 ± 1.1
Fasting plasma glucose [mmol/L]	776 (77.4)	5.9 ± 1.5
Serum creatinine [µmol/L]	890 (88.7)	82.1 ± 27.3
GFR [ml/min per 1.73m²]	890 (88.7)	91.4 ± 46.2
Albumin/creatinine ratio	75 (7.5)	5.3 ± 12.6

SD: standard deviation; OBPM: office blood pressure measurement; SBP: systolic blood pressure; DBP: diastolic blood pressure; HR_rest: heart rate at rest; BMI: body mass index; WC: waist circumference; HDL: high density lipoprotein; LDL: low density lipoprotein; GFR: glomerular filtration rate.

BP categories

BP categories based on OBPM are given in Table 2. Most patients (85.2%) had an established diagnosis of hypertension and were on antihypertensive treatment for a mean time period since diagnosis of 10.2 ± 8.2 years. The remaining 14.8% were first diagnosed with hypertension when included into HccH. At the time of enrolment, BP was controlled (<140/90 mmHg) in 33.0% of patients.

Table 2.

Hypertension grades based on office blood pressure measurement according to 2013 European Society of Hypertension/European Society of Cardiology Guidelines for the management of arterial hypertension (n = 1003).

Blood pressure categories	n (%)
Normal	116 (11.6)
High normal	215 (21.4)
Grade 1 hypertension	424 (42.3)
Grade 2 hypertension	179 (17.8)
Grade 3 hypertension	69 (6.9)

Normal: systolic blood pressure (SBP) 120–129/diastolic blood pressure (DBP) 80–84 mmHg; high normal: SBP 130–139/DBP 85–89 mmHg; Grade 1 hypertension: SBP 140–159/DBP 90–99 mmHg; Grade 2 hypertension: SBP 160–179/DBP 100–109 mmHg; Grade 3 hypertension: SBP ≥ 180 DBP ≥ 110 mmHg.

Cardiovascular risk stratification

Relative to the number of available datasets, the most prevalent cardiovascular risk factors in decreasing order were dyslipidaemia, age (≥55 years in men, ≥65 years in women) and abdominal obesity (see Table 3). The most common subclinical organ damage was mild CKD, followed by microalbuminuria and LVH. Using echocardiography, detection rate of LVH was substantially higher than with electrocardiogram (ECG) (31.4% vs. 2.2%). However, echocardiography was performed less frequently than ECG (22.8% vs. 77.5%). Coronary heart disease was reported as the most frequent established organ damage, followed by history of myocardial infarction.

Table 3.

Prevalence of CV risk factors, DM, and subclinical and established OD (n = 1003).

Parameters	n (%)	Missing data n (%)
CV risk factors
Age [m: ≥ 55, f: ≥ 65 years]	684 (68.2)	0 (0.0)
Smoking	164 (16.4)	1 (0.1)
Obesity	307 (30.6)	0 (0.0)
Abdominal obesity	54 (65.9)	921 (91.8)
PFPG	262 (33.7)	227 (22.6)
Dyslipidaemia	703 (80.0)	125 (12.5)
CV family history	142 (26.5)	467 (46.6)
DM and subclinical OD
DM	254 (25.3)	0 (0.0)
LVH	100 (12.6)	213 (21.2)
Microalbuminuria	42 (15.3)	728 (72.6)
Mild CKD	167 (18.7)	113 (11.3)
Established CV/renal disease
Coronary heart disease	116 (11.6)	1 (0.1)
Stroke, TIA	36 (3.6)	1 (0.1)
Myocardial infarction	49 (4.9)	1 (0.1)
Congestive heart failure	26 (2.6)	1 (0.1)
PAD	46 (4.6)	1 (0.1)
Severe CKD	10 (1.1)	113 (11.3)

The given percentages (%) refer to the number (n) of available datasets.

CV: cardiovascular; m: male; f: female; DM: diabetes mellitus; OD: organ damage; PFPG: pre-diabetic fasting plasma glucose; LVH: left ventricular hypertrophy; CKD: chronic kidney disease; TIA: transient ischemic attack; PAD: peripheral artery disease.

Mean OBPM was significantly different in male patients, with 144/86 mmHg compared with female patients with 147/85 mmHg (p < 0.001). Evaluation of cardiovascular risk factors showed that men were significantly older and more often smokers (p < 0.001). Prevalence of obesity, dyslipidaemia, pre-diabetic fasting plasma glucose, diabetes mellitus and positive cardiovascular family history were comparable in both sexes. Regarding signs for subclinical organ damage, microalbuminuria was more frequent in male patients (p < 0.05), whereas the prevalence of mild CKD was significantly higher in females (p < 0.001). Coronary heart disease (p < 0.01) and myocardial infarction (p < 0.05) were significantly more common in male patients. Stroke, TIA, congestive heart failure and PAD did not differ between sexes, whereas severe CKD was more frequent in females (p < 0.05).

The analysis of cardiovascular risk factors across age categories (see Table 4) revealed that pre-diabetic fasting plasma glucose and diabetes mellitus were significantly more prevalent in older patients, while younger patients showed a higher smoking prevalence. Obesity was most frequent in the middle age category from 50 to 75 years. Our data also demonstrated that subclinical and established organ damage were significantly more common in the elderly.

Table 4.

CV risk data by age category (n = 1003).

Age categories: Parameters	n	<50 years %	50–75 years %	>75 years %	p-value
CV risk factors
Smoking	1003	24.8	17.7	7.2	<0.001
Obesity	1003	32.6	34.2	18.9	<0.001
Abdominal obesity	82	52.9	66.7	81.8	0.283
PFPG	776	25.7	26.7	29.7	0.046
Dyslipidaemia	878	60.9	72.7	68	0.087
CV family history	536	30.2	27.3	19.3	0.210
DM and subclinical OD
DM	1003	10.9	25.5	33.8	<0.001
LVH	790	2.9	9.6	15.3	0.020
Microalbuminuria	275	15.4	13.4	22.0	0.328
Mild CKD	890	0.0	9.1	54.8	<0.001
Established CV/renal disease
CV diseases	1003	1.5	18.5	39.6	<0.001
Severe CKD	890	0.0	0.2	4.3	<0.001

Significant p-values are highlighted in bold. The given percentages (%) refer to the number (n) of available datasets.

CV: cardiovascular; PFPG: pre-diabetic fasting plasma glucose; DM: diabetes mellitus; OD: organ damage; LVH: left ventricular hypertrophy; CKD: chronic kidney disease.

Cardiovascular risk profile

Only 1.7% of patients did not have any cardiovascular risk factors besides arterial hypertension, while 19.7% had one or two additional risk factors, and 27.3% had three or more risk factors (see Figure 2). In 29.9% of patients, subclinical organ damage, diabetes mellitus or mild CKD (stage 3) was found, and 21.3% had an established cardiovascular and/or renal disease. Taken together, 78.5% of patients included into HccH either had three or more CV risk factors, diabetes mellitus, and subclinical or established organ damage. Based on the 2013 ESH/ESC Guidelines taking into account BP grades at the time of enrolment, 11.1% of patients were at low or low-to-moderate cardiovascular risk, 9.4% at moderate risk, 23.5% at moderate-to-high risk, 27.7% at high or high-to-very-high risk and 16.7% at very high risk, indicating a high cardiovascular risk in the majority of patients (Table 5). High-to-very-high-risk patients were significantly older (p < 0.001) with a higher prevalence of obesity and pre-diabetic fasting plasma glucose (both p < 0.05) compared with patients at low-to-moderate cardiovascular risk.

Figure 2.

This figure depicts the percentage of additional cardiovascular risk factors as categorized by the 2013 European Society of Hypertension/European Society of Cardiology Guidelines.¹³

Table 5.

Assignment of CV risk category to 10-year risk for CV morbidity and mortality.

CV risk category	n	%	10-year risk for CV morbidity and mortality
Average risk	116	11.6
Low	45	4.5	<15%
Low-to-moderate	66	6.6
Moderate	94	9.4	15–20%
Moderate-to-high	236	23.5
High	254	25.3	20–30%
High-to-very high	24	2.4
Very high	168	16.7	≥30%
Total	1003	100.0

Cardiovascular (CV) risk was categorized according to the 2013 European Society of Hypertension/European Society of Cardiology Guidelines¹³ and the 10-year risk for CV morbidity and mortality was estimated using the Framingham criteria.^17,18

Discussion

The findings of this study investigating patients with arterial hypertension in Swiss primary care indicated that BP control (<140/90 mmHg) at the time of enrolment was low (33.0%) and that 44.4% of hypertensive patients had a high or very high overall cardiovascular risk, corresponding to a 10-year risk for cardiovascular morbidity and mortality of more than 20%. A high proportion of patients (78.5%) presented with either more than three cardiovascular risk factors, diabetes mellitus, subclinical or established organ damage. Information on sex, age, smoking status, BMI, diabetes mellitus and established cardiovascular diseases were collected mostly completely (all ≤ 0.1% missing data), whereas data collection was incomplete with regard to waist circumference (abdominal obesity), microalbuminuria and cardiovascular family history, which were recorded in only 8.2%, 27.4% and 53.4% of patients, respectively.

Cardiovascular risk profile

The low rate of controlled BP in this cohort emphasizes the need for comprehensive cardiovascular risk stratification and adequate treatment of arterial hypertension. Our results are largely comparable with those of the PRESCAP 2006 study performed in primary care centres in Spain, showing that approximately half of the patients treated for hypertension had a high (33.5%) or very high cardiovascular risk (18.4%).¹⁹ The high prevalence of cardiovascular risk factors in our study is comparable with the findings of Barrios et al., who also demonstrated that age and dyslipidaemia were the most common cardiovascular risk factors in hypertensive patients in a primary care setting.²⁰ A population-based study has recently shown that obesity (50%), hypertension (47%) and hypercholesterolaemia (33%) are the leading cardiovascular risk factors in Switzerland, while smoking (13%) and diabetes mellitus (1.6%) were less prevalent than in our cohort.²¹ Prevalence of established organ damage was consistent with other studies, showing that coronary heart disease was the most reported organ damage.^19,20,22 Frequency of LVH as a sign of subclinical organ damage in hypertensive patients varies in the literature from 7.5% to 22.1%.^22–24 In the present study, a prevalence of 12.6% for LVH was detected when taking into account either ECG or echocardiography. In this study, microalbuminuria was present in 15.3% of patients, which was comparable with other studies.^23,25 Testing for microalbuminuria is not yet routinely performed in clinical practice,²⁶ although it is an established marker for subclinical organ damage according to the 2013 ESH/ESC Guidelines.¹³ Dieterle et al. showed that urinalysis for detection of microalbuminuria affects therapeutic decisions, mainly in patients at low or moderate cardiovascular risk, where immediate drug treatment is indicated.²⁶ The inclusion of data on microalbuminuria increased the percentage of patients with high cardiovascular risk from 59.4% to 66.0%. Therefore, systematic testing for microalbuminuria is important for comprehensive diagnosis and risk assessment in patients with arterial hypertension.

Cardiovascular risk stratification and the impact of missing data

Hypertension management should be based on individual cardiovascular risk assessment. Therefore, comprehensive risk stratification is of great value. The present results showed that most cardiovascular risk factors were documented with high completeness. However, substantial gaps were found for the measurement of waist circumference, which was missing in 91.8% of patients, as well as for the assessment of cardiovascular family history, which was missing in 46.6% of cases. Diabetes mellitus was recorded in all patients and creatinine levels to evaluate GFR were determined in almost 90% of patients. In contrast, screening for subclinical organ damage, such as microalbuminuria or LVH, was performed inconsistently. On the other hand, documentation of established cardiovascular disease was largely complete, demonstrating that about every fifth hypertensive patient suffered from cardiovascular disease. Nevertheless, incomplete recording of data on subclinical organ damage seen in HccH indicates that cardiovascular risk might be substantially underestimated in patients with arterial hypertension.²⁷ Since cardiovascular risk affects both timing and selection of antihypertensive treatment, it is apparent that a more comprehensive approach for risk stratification could result in earlier and more targeted antihypertensive therapy, thereby beneficially affecting prognosis in these patients.

Implications for clinical practice

Increasing the number of parameters to determine overall cardiovascular risk in the individual patient is beneficial, but may also have its drawbacks. It is conceivable that the more risk factors are evaluated, the more accurate the risk estimate will be. However, the value of adding further risk factors to the risk stratification process may be limited by only minor incremental improvements with regard to the accuracy of risk estimates.²⁸ Furthermore, including a higher number of risk factors may result in a more complex, time-consuming and costly risk stratification process that may no longer be feasible in daily clinical practice. Therefore, besides statistical considerations the incremental benefit and cost-effectiveness of including additional risk factors in the risk stratification process need to be taken into account.²⁹ In this respect, the 2013 ESH/ESC Guidelines provide guidance on the selection of relevant and cost-effective screening tests.¹³ However, the results of this study suggest that guidelines are not fully implemented in Swiss primary care yet. In particular, this applies to the awareness of the importance of comprehensive assessment of subclinical organ damage. Potential approaches may include targeted education activities and improved communication of guideline recommendations, as well as incentivizing GPs to integrate comprehensive risk stratification processes in daily practice. In addition, our data demonstrate that the assessment of physical activity is not an integral part of cardiovascular risk stratification in Switzerland. In view of recent publications demonstrating beneficial effects of regular physical exercise on the incidence of arterial hypertension as well as on BP control, particular importance should be attached to this topic.³⁰

Limitations

Several points should be considered as potentially limiting the interpretation and generalizability of the results of this study. Since decisions on patient recruitment as well as on the diagnosis of arterial hypertension, subclinical organ damage and comorbidities were at the discretion of the treating GP, a selection and inclusion bias cannot be completely excluded. In addition, cardiovascular risk in this cohort may have been underestimated due to numerous missing data. Nevertheless, baseline patient characteristics in this study were comparable with those found in previous studies. Moreover, being performed in a real-world setting, the results of this study adequately reflect the current situation and the challenges related to the management of arterial hypertension in Swiss primary care.

Conclusion

The HccH demonstrated a high rate of cardiovascular risk factors, subclinical organ damage and established cardiovascular and renal disease in primary care patients with arterial hypertension assessed in a cross-sectional approach. Despite treatment with either antihypertensive drugs and/or lifestyle modifications, almost half of the patients continued to have a high or very high overall cardiovascular risk. While cardiovascular risk factors, diabetes mellitus, and concomitant cardiovascular and renal disease were recorded with high completeness, screening for subclinical organ damage was incomplete, indicating that cardiovascular risk in primary care may be substantially underestimated. As a consequence, adequate measures should be taken to improve the process of cardiovascular risk stratification, since the detection of subclinical organ damage yields important information about cardiovascular risk and provides the basis for targeted antihypertensive treatment.

Footnotes

Author contribution

Authors AH and SBZ contributed equally to this manuscript. BM, PT, AZ and TD contributed to the conception or design of the work. All contributed to the acquisition, analysis, or interpretation of data for the work. AH, SBZ, JM and TD drafted the manuscript. SG, CG, BM, PT, JDL, AZ and TD critically revised the manuscript. All authors gave final approval and agree to be accountable for all aspects of work ensuring integrity and accuracy.

Acknowledgements

The authors of this study would like to thank all participating GPs and in particular the physicians’ network of northwestern Switzerland for their highly appreciated support in patient recruitment. Part of this work was presented at the Annual Meeting of the Swiss Society of Internal Medicine 2015 in Basel, Switzerland. FM253: A Handschin, A Zeller, P Tschudi, B Martina, J Leuppi, T Dieterle. Cardiovascular risk profile and blood pressure control in treated hypertensive patients – an analysis from the Swiss hypertension cohort study.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: grants were received from the Swiss Society of Hypertension, Berne, Switzerland, Gottfried and Julia Bangerter-Rhyner-Foundation, Switzerland, Laboratory Rothen Basel, Switzerland, MSD Chibret AG Switzerland, Novartis Pharma Switzerland, Pfizer Pharma Switzerland, Robapharm Switzerland, Sandoz Pharma Switzerland, Sankyo Pharma Switzerland, and Spirig Pharma AG, Switzerland.

References

Forouzanfar

Liu

Roth

, et al. Global burden of hypertension and systolic blood pressure of at least 110 to 115 mm Hg, 1990–2015. JAMA 2017; 317: 165–182.

MacMahon S, Peto R, Cutler J, et al. Blood pressure, stroke, and coronary heart disease. Part 1, prolonged differences in blood pressure: Prospective observational studies corrected for the regression dilution bias. Lancet 1990; 335: 765–774.

Lewington

Clarke

Qizilbash

, et al. Prospective Studies Collaboration. Age-specific relevance of usual blood pressure to vascular mortality: A meta-analysis of individual data for one million adults in 61 prospective studies. Lancet 2002; 360: 1903–1913.

Lim

Vos

Flaxman

, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: A systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380: 2224–2260.

Walther

Curjuric

Dratva

, et al. High blood pressure: Prevalence and adherence to guidelines in a population-based cohort. Swiss Med Wkly 2016; 146: w14323–w14323.

Kannel

Wolf

McGee

, et al. Systolic blood pressure, arterial rigidity, and risk of stroke. The Framingham study. JAMA 1981; 245: 1225–1229.

Vasan

Levy

. The role of hypertension in the pathogenesis of heart failure. A clinical mechanistic overview. Arch Intern Med 1996; 156: 1789–1796.

Levy

Larson

Vasan

, et al. The progression from hypertension to congestive heart failure. JAMA 1996; 275: 1557–1562.

Strano

Novo

Avellone

, et al. Hypertension and other risk factors in peripheral arterial disease. Clin Exp Hypertens 1993; 1: 71–89.

10.

Tozawa

Iseki

, et al. Blood pressure predicts risk of developing end-stage renal disease in men and women. Hypertension 2003; 41: 1341–1345.

11.

World Health Organization. A global brief on hypertension. Silent killer, global public health crisis. World Health Day 2013, Geneva, http://apps.who.int/iris/bitstream/10665/79059/1/WHO_DCO_WHD_2013.2_eng.pdf?ua=1 (2013, accessed 22 October 2018).

12.

Wieser S, Tomonaga Y, Riguzzi M, et al. The costs of non-communicable diseases in Switzerland. Winterthur, https://www.zora.uzh.ch/id/eprint/103453/1/wieser-kostendernichtuebertragbare.pdf (2014, accessed 22 October 2018).

13.

Mancia

Fagard

Narkiewicz

, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). J Hypertens 2013; 31: 1281–1357.

14.

Polonia

Mesquita-Bastos

Pessanha

, et al. Global cardiovascular risk stratification of hypertensive patients followed in Portugal in primary care or in hospital care according to the 2007 ESH/ESC guidelines. Rev Port Cardiol 2010; 29: 1685–1696.

15.

Kim

Lee

Park

. Impact of global risk assessment on the evaluation of hypertensive patients treated by primary care physicians in Korea (a nation-wide, multi-center, observational, cross-sectional, epidemiologic study to evaluate the proportion of cardiovascular risk factors in Korean hypertensive patients: WONDER study). Hypertens Res 2014; 37: 665–671.

16.

Zeller

Haehner

Battegay

, et al. Diagnostic significance of transferrinuria and albumin-specific dipstick testing in primary care patients with elevated office blood pressure. J Hum Hypertens 2005; 19: 205–209.

17.

D’Agostino

Sr Grundy

Sullivan

, et al. CHD Risk Prediction Group. Validation of the Framingham coronary heart disease prediction scores: Results of a multiple ethnic groups investigation. JAMA 2001; 286: 180–187.

18.

D’Agostino

Sr Vasan

Pencina

, et al. General cardiovascular risk profile for use in primary care: The Framingham Heart Study. Circulation 2008; 117: 743–753.

19.

Rodriguez-Roca

Llisterri-Caro

Barrios-Alonso

, et al. Cardiovascular risk and blood pressure control in a Spanish hypertensive population attended in a Primary Care setting. Data from the PRESCAP 2006 study. Blood Press 2009; 18: 117–125.

20.

Barrios

Escobar

Calderon

, et al. Cardiovascular risk profile and risk stratification of the hypertensive population attended by general practitioners and specialists in Spain. The CONTROLRISK study. J Hum Hypertens 2007; 21: 479–485.

21.

Nedeltchev

Arnold

Baumgartner

, et al. Vascular risk factors in the Swiss population. J Neurol 2005; 252: 1210–1216.

22.

Brenner

Waeber

Allemann

. Medical treatment of hypertension in Switzerland. The 2009 Swiss Hypertension Survey (SWISSHYPE). Swiss Med Wkly 2011; 141: w13169–w13169.

23.

Danon-Hersch

Marques-Vidal

Bovet

, et al. Prevalence, awareness, treatment and control of high blood pressure in a Swiss city general population: The CoLaus study. Eur J Cardiovasc Prev Rehabil 2009; 16: 66–72.

24.

Macfadyen

. The 2007 revised ESC/ESH Guidelines in the management of hypertension: Clarifying individual patient care. J Hum Hypertens 2007; 21: 757–761.

25.

Pewsner

Juni

Egger

, et al. Accuracy of electrocardiography in diagnosis of left ventricular hypertrophy in arterial hypertension: Systematic review. BMJ 2007; 335: 711–711.

26.

Dieterle

Sigle

Bengel

, et al. Cardiovascular risk stratification in unselected primary care patients with newly detected arterial hypertension. Hypertens Res 2010; 33: 607–615.

27.

Viazzi

Leoncini

Parodi

, et al. Impact of target organ damage assessment in the evaluation of global risk in patients with essential hypertension. J Am Soc Nephrol 2005; 1: 89–91.

28.

Pencina

D’Agostino

Sr D’Agostino

Jr , et al. Evaluating the added predictive ability of a new marker: From area under the ROC curve to reclassification and beyond. Stat Med 2008; 27: 157–172. discussion 207–112.

29.

Greenland

. The need for reorientation toward cost-effective prediction: Comments on ‘Evaluating the added predictive ability of a new marker: From area under the ROC curve to reclassification and beyond’ by M. J. Pencina et al., Statistics in Medicine (DOI: 10.1002/sim.2929). Stat Med 2008; 27: 199–206.

30.

Lee

Ryu

Sung

. Association of baseline level of physical activity and its temporal changes with incident hypertension and diabetes mellitus. Eur J Prev Cardiol 2018; 25: 1065–1073.