Email updates

Keep up to date with the latest news and content from BMC Family Practice and BioMed Central.

Open Access Highly Accessed Research article

Prevalence of target organ damage in hypertensive subjects attending primary care: C.V.P.C. study (epidemiological cardio-vascular study in primary care)

Athanasia Papazafiropoulou12*, Efstathios Skliros13, Alexios Sotiropoulos12, Christos Papafragos13, Aristofanis Gikas14, Ourania Apostolou12, Hariklia Kaliora13 and Charalambos Tountas1

Author Affiliations

1 Hellenic Association of Research and Continuing Education in Primary Care, Athens, Greece

2 3rd Department of Internal Medicine and Center of Diabetes, General Hospital of Nikaia "Ag. Panteleimon" - Piraeus, Greece

3 Nemea Health Center, Nemea, Korinthia, Greece

4 Department of General Practice, Health Centre of Kalivia, Kalivia-Lagonisi, Athens, Greece

For all author emails, please log on.

BMC Family Practice 2011, 12:75  doi:10.1186/1471-2296-12-75


The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2296/12/75


Received:12 February 2011
Accepted:14 July 2011
Published:14 July 2011

© 2011 Papazafiropoulou et al; licensee BioMed Central Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

Except for the established risk factors, presence of target organ damage has an important role in the treatment of hypertensive subjects. The aim of the present study was to estimate the prevalence of target organ damage in primary care subjects.

Methods

This multi-centre, cross-sectional survey of 115 primary care physicians recruited 1095 consecutive subjects with hypertension: 611 men (55.8%); and 484 women (44.2%). A detailed history for the presence of cardiovascular disease and a thorough clinical examination was performed to each subject.

Results

Of the total study population, 44.5% (n = 487) had target organ damage (33.0% had left ventricular hypertrophy, 21.8% increased carotid intima media thickness, 11.0% elevated plasma creatinine levels and 14.6% microalbuminuria). Target organ damage was more prevalent in males than in females (P = 0.05). In addition, males had more often increased carotid intima media thickness than females (P = 0.009). On the contrary, females had more often microalbuminuria (P = 0.06) than males. No differences were observed between the two genders regarding left ventricular hypertrophy (P = 0.35) and elevated plasma creatinine levels (P = 0.21). Logistic regression analysis showed associations between target organ damage and dyslipidemia (P < 0.001), presence of metabolic syndrome (P = 0.005), diabetes (P < 0.001) and coronary artery disease (P < 0.001).

Conclusion

A significant proportion of hypertensive subjects in primary care had documented associated target organ damage, with left ventricular hypertrophy being the most prevalent target organ damage.

Keywords:
Primary care; hypertension; target organ damage; left ventricular hypertrophy

Background

Arterial hypertension has been recognized as one of the major cardiovascular risk factors and management of hypertensive subjects still remains a challenge for the clinicians [1]. Except for the established risk factors [age, gender, family history of cardiovascular disease, smoking, obesity, dyslipidemia and diabetes mellitus (DM)], presence of subclinical target organ damage (TOD) (left ventricular hypertrophy, carotid atheromatosis and renal impairment) has an important role in the treatment of hypertensive subjects and the prevention of cardiovascular disease [2,3].

It has been showed that subclinical TOD is a marker of increased cardiovascular morbidity and mortality [4-9]. Hypertensive subjects with left ventricular hypertrophy (LVH) [4], increased carotid intima media thickness (IMT) [5] and microalbuminuria [6-9] show increased cardiovascular risk. In addition, hypertensive subjects with apparent macrovascular disease [cerebrovascular disease, coronary artery disease (CAD) and peripheral artery disease] have increased cardiovascular risk [9]. Therefore, knowledge of the presence of TOD is of major importance for the optimal management of subjects with arterial hypertension. However, little data exist regarding the prevalence of TOD in primary care subjects in our country. The aim of the present study was to estimate the prevalence of TOD in primary care subjects.

Methods

Population

The C.V.P.C. study (Epidemiological Cardio-Vascular Study in Primary Care) was a multi-center, cross-sectional survey which was carried out in order to determine the prevalence of TOD in subjects with hypertension in primary care. The survey included 1095 subjects with a known history of hypertension, 611 men (55.8%) and 484 women (44.2%) who consecutively attended 115 Primary care physicians from 1-10-2009 until 31-10-2009. Only 21 subjects refused to take part in the study. Patient's medical history recording and physical examination was performed by the physicians that took part in the study. All data were documented in patients' records.

A detailed history for the presence of cardiovascular disease, TOD, current medication, information about other diseases and smoking habits was obtained, and a physical examination was performed. Body weight with subjects in light clothing without shoes and height was measured and body mass index (BMI) was calculated. Waist circumference was measured with a soft tape on standing, midway between the lowest rib and the iliac crest. The biochemical parameters were recorded from laboratory testing in the three months prior to consultation (or in the days after consultation if no such prior testing proved available) at local biochemical laboratories.

Blood pressure was measured three consecutive times, one minute in apart, in the sitting position after 5 minutes rest period using an appropriate cuff size. All the measurements performed using the A & D UA-705 Upper Arm Blood Pressure Monitor The mean values of the last 2 measurements was calculated and used in the analysis. Arterial hypertension was defined according to the current guidelines [10], when systolic was ≥ 140 mmHg or and/or diastolic blood pressure was ≥ 90 mmHg or when the patients were on antihypertensive treatment. In addition the type of the antihypertensive treatment was recorded. The controlled hypertension definition was based on systolic blood pressure ≤ 140 mmHg and diastolic blood pressure ≤ 85 mmHg in subjects taking antihypertensive medications.

Dyslipidemia was defined when patients were on statin treatment. CAD was defined as presence of angina, history of previous myocardial infarction, positive stress testing, revascularization procedures or stenosis > 50% at the coronary arteries. DM was self-reported and defined as current use of antidiabetic treatment. Renal impairment was defined as plasma creatinine levels ≥ 1.3 mg/dl. Microalbuminuria was defined as 24 hour urinary albumin of 30-300 mg/dl. Presence of LVH and increased carotid IMT were reported according to subject's recent ultrasound examination. Subjects having three or more of the following criteria (according to the NCEP ATP III report) [11], were defined as having the metabolic syndrome (MS): abdominal obesity (waist circumference > 102 cm in men and > 88 cm in women), triglycerides ≥ 150 mg/dl, HDL cholesterol: ≤ 40 mg/dl in men and ≤ 50 mg/dl in women, high blood pressure: ≥ 130/85 mmHg or use of antihypertensive drugs and high fasting plasma glucose: ≥ 100 mg/dl or treatment for diabetes mellitus. Measurement of carotid IMT was performed by carotid ultrasound examination that measured the thickness of the intimal and medial layers of the arterial wall (IMT >0.9 mm in the common carotid artery is a known cardiovascular risk factor) [12]. Retinal examination was carried out by experienced ophthalmologists with no prior knowledge of the participants' blood pressure level.

The study protocol was reviewed by the bioethical committee of the Hellenic Association of Research and Continuing Education in Primary Care and a written consent was obtained from all participants.

Statistical analyses

Data are expressed as mean ± standard deviation (SD). Student's t-tests and pearson's χ2 test was used to compare between-groups differences. Logistic regression analysis with a backward stepwise approach was employed to identify variables associated with TOD. Relative risks (RR) were calculated from logistic regression models. Any P value ≤ 0.05 (two-tailed) was considered statistically significant. Data were analyzed using SPSS v 15.0 (SPSS, Chicago, IL, USA).

Results

The basic demographic characteristics of the study subjects are showed in Table 1. Two hundred eighty one (25.7%) subjects had a family history of cardiovascular disease and 28.4% (n = 311) patients had MS. Smokers were 38.9% of the study population. The most frequent co-morbidities were DM (25.8%) and dyslipidemia (59.5%); followed by peripheral artery disease (12.2%), CAD (11.9%), retinopathy (7.2%), heart failure (7.0%) and cerebrovascular disease (4.9%).

Table 1. Characteristics of the studied population [data are showed as Mean ± SD or n (%)]

Blood pressure control

56.8% of the subjects, (n = 622) had blood pressure levels that were considered well-controlled (< 140/85 mmHg). The above targets for blood pressure were achieved by 63.1% of the subjects with CAD, 53.5% of the subjects with TOD and 46.6% of the diabetic subjects. Of the subjects achieved blood pressure levels 12.5% were on single anti-hypertensive agent, 60.0% on dual anti-hypertensive agents and 27.5% were prescribed ≥3 anti-hypertensive drugs.

Target organ damage

Of the total study population, 44.5% (n = 487) had documented TOD (33.0% had LVH, 21.8% increased carotid IMT, 11.0% elevated plasma creatinine levels and 14.6% microalbuminuria). TOD was more prevalent in males than in females (49.1% vs. 43.0%, respectively, P = 0.05). In addition, males had more often increased carotid IMT than females (25.5% vs. 18.8%, respectively, P = 0.009). On the contrary, females had more often microalbuminuria (17.5% vs. 13.4%, respectively, P = 0.06) than males. No differences were observed between the two genders regarding LVH (34.5% vs. 31.9%, respectively, P = 0.35) and elevated plasma creatinine levels (10.3% vs. 12.9%, respectively, P = 0.21) (Table 2).

Table 2. Prevalence of target organ damage among hypertensive subjects attending primary care

Of the subjects with dyslipidemia, 53.5% (n = 348) had documented TOD (41.0% had LVH, 27.5% increased carotid IMT, 14.3% elevated plasma creatinine levels and 18.6% microalbuminuria). Of the subjects with MS, 61.7% (n = 192) had documented TOD (49.2% had LVH, 29.9% increased carotid IMT, 21.5% elevated plasma creatinine levels and 30.9% microalbuminuria). Of the diabetic subjects, 62.2% (n = 176) had documented TOD (45.9% had LVH, 33.2% increased carotid IMT, 27.2% elevated plasma creatinine levels and 36.0% microalbuminuria).

Logistic regression analysis showed associations between TOD and dyslipidemia [odds ratio (OR): 2.04, 95% Confidence Intervals (95% CI): 1.52-2.73, P < 0.001], presence of MS (OR = 1.64, 95% CI: 1.16-2.31, P = 0.005), DM (OR = 1.93, 95% CI: 1.36-2.7, P < 0.001) and CAD (OR = 4.06, 95% CI: 2.44-6.76, P < 0.001).

Discussion

In the present study we showed that a significant proportion of hypertensive subjects in primary care had documented associated TOD. LVH was the most prevalent TOD followed by increased carotid IMT and renal impairment. In addition, TOD was more prevalent in hypertensive males than in females. Studies from different populations have demonstrated a high percentage of TOD among hypertensive subjects [13-19]. Studies from the U.S.A. [13], Africa [14-17] and Europe [18,19] have showed high prevalence of TOD in hypertensive subjects. In addition, in African hypertensive subjects, males had higher odds of developing TOD compared to females [14]. It is well established that presense, even subclinical, of TOD is associated with increased cardiovascular mortality [4-9]. In addition, hypertensive subjects with LVH [4], increased IMT [5] and microalbuminuria [6-9] show increased cardiovascular risk. Therefore, presence of TOD has an important role in the treatment of hypertensive subjects and the prevention of cardiovascular disease [2,3]. Knowledge of prevalence of TOD in primary care might help to early detection and intensive treatment of subjects at high cardiovascular risk.

It is known that TOD already exists in newly diagnosed hypertensive subjects [20]. A recent study in our country showed that subjects with white coat and masked hypertension had TOD in terms of LVH and increased carotid IMT [21]. It is noteworthy, that even at early stages of hypertension TOD is present resulting at increased cardiovascular risk among hypertensive subjects [20,21]. Confirming previous studies, we showed that LVH was the most prevalent TOD in hypertensive subjects [13,15-17] followed by renal impairment [13,19].

Logistic regression analysis showed associations between TOD and presence of MS, dyslipidemia, DM and CAD. In hypertensive subjects MS, as a clustering of cardiovascular risk factors, amplifies TOD [22-24]. A recent study showed that the risk of LVH, carotid abnormalities and microalbuminuria increased by the presence of MS even after adjusting for several confounders [22]. Another study found a strong association between MS and TOD by showing that a clustering of two or three markers of TOD is the prevalent cardiovascular phenotype in MS hypertensive subjects [24]. A study in this elderly non-diabetic hypertensive subjects showed that the presence of MS was independently related to a greater prevalence of TOD and established cardiovascular disease [24].

In addition, DM and CAD per se have been associated with TOD in hypertensive subjects [16,19]. TOD tends to be more prevalent in hypertensive diabetic patients than in non-diabetics [25], as is the case in subjects with MS [26]. Another study found a relationship between TOD and established cardiovascular disease [19]. In fact, the prevalence of established cardiovascular disease was twice as great in hypertensive subjects with LVH and renal impairment [19]. Finally, despite previous findings, in the present study we failed to demonstrate any association between TOD and blood pressure levels [14,15].

Limitations

The present study has its limitations. In the present study only subjects with a known history of arterial hypertension where included and therefore a selection bias could not be avoided. In addition, information regarding the duration of antihypertensive treatment and diabetes are missing. Another limitation is that measurements were obtained by biochemical laboratories at different regions and not a central one.

Conclusion

In conclusion, a significant proportion of hypertensive subjects in primary care had documented associated TOD, with LVH being the most prevalent TOD. The above finding emphasizes the important role of the primary care clinicians to the early detection, treatment and control of high blood pressure that might help to reducing overall cardiovascular risk.

Competing interests

The authors declare that they have no competing interests.

Authors' contributions

ES, CP, AG, OA, HK and MS participated in the collection of the data. AP, ES, AS and CT participated in the design of the study and performed the statistical analysis and drafted the manuscript. All authors read and approved the final manuscript.

Acknowledgements

The study was supported by a grant of Menarini Hellas.

References

  1. Kaplan NM: Hypertension in the population at large. In Kaplan's Clinical Hypertension. 8th edition. Edited by Kaplan NM. Baltimore, Lippincott Williams & Wilkins; 2002:1-2. PubMed Abstract | Publisher Full Text OpenURL

  2. Ogden LG, He J, Lydick E, Whelton PK: Long-term absolute benefit of lowering blood pressure in hypertensive patients according to the JNC VI risk stratification.

    Hypertension 2000, 35:539-43. PubMed Abstract | Publisher Full Text OpenURL

  3. Leoncini G, Sacchi G, Viazzi F, Ravera M, Parodi D, Ratto E, Vettoretti S, Tomolillo C, Deferrari G, Pontremoli R: Microalbuminuria identifies global cardiovascular risk in essential hypertension: An artificial neural network-based approach.

    J Hypertens 2002, 20:1315-21. PubMed Abstract | Publisher Full Text OpenURL

  4. Ghali JK, Liao Y, Cooper RS: Influence of left ventricular geometric patterns on prognosis in patients with or without coronary artery disease.

    J Am Coll Cardiol 1998, 31:1635-40. PubMed Abstract | Publisher Full Text OpenURL

  5. O'Leary DH, Polak JF, Kronmal RA, Manolio TA, Burke GL, Wolfson SK Jr: Carotid-artery intima and media thickness as a risk factor for myocardial infarction and stroke in older adults. Cardiovascular Health Study Collaborative Research Group.

    N Engl J Med 1999, 340:14-22. PubMed Abstract | Publisher Full Text OpenURL

  6. Pontremoli R: Microalbuminuria in essential hypertension--Its relation to cardiovascular risk factors.

    Nephrol Dial Transplant 1996, 1:2113-5. OpenURL

  7. Pontremoli R, Ravera M, Bezante GP, Viazzi F, Nicolella C, Berruti V, Leoncini G, Del Sette M, Brunelli C, Tomolillo C, Deferrari G: Left ventricular geometry and function in patients with essential hypertension and microalbuminuria.

    J Hypertens 1999, 17:993-1000. PubMed Abstract | Publisher Full Text OpenURL

  8. Jensen JS, Feldt-Rasmussen B, Strandgaard S, Schroll M, Borch-Johnsen K: Arterial hypertension, microalbuminuria, and risk of ischemic heart disease.

    Hypertension 2000, 35:898-903. PubMed Abstract | Publisher Full Text OpenURL

  9. Mancia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, Grassi G, Heagerty AM, Kjeldsen SE, Laurent S, Narkiewicz K, Ruilope L, Rynkiewicz A, Schmieder RE, Struijker Boudier HA, Zanchetti A, Vahanian A, Camm J, De Caterina R, Dean V, Dickstein K, Filippatos G, Funck-Brentano C, Hellemans I, Kristensen SD, McGregor K, Sechtem U, Silber S, Tendera M, Widimsky P, Zamorano JL, Kjeldsen SE, Erdine S, Narkiewicz K, Kiowski W, Agabiti-Rosei E, Ambrosioni E, Cifkova R, Dominiczak A, Fagard R, Heagerty AM, Laurent S, Lindholm LH, Mancia G, Manolis A, Nilsson PM, Redon J, Schmieder RE, Struijker-Boudier HA, Viigimaa M, Filippatos G, Adamopoulos S, Agabiti-Rosei E, Ambrosioni E, Bertomeu V, Clement D, Erdine S, Farsang C, Gaita D, Kiowski W, Lip G, Mallion JM, Manolis AJ, Nilsson PM, O'Brien E, Ponikowski P, Redon J, Ruschitzka F, Tamargo J, van Zwieten P, Viigimaa M, Waeber B, Williams B, Zamorano JL: The task force for the management of arterial hypertension of the European Society of Hypertension, The task force for the management of arterial hypertension of the European Society of Cardiology. Guidelines for the management of arterial hypertension.

    Eur Heart J 2007, 28:1462-536. PubMed Abstract | Publisher Full Text OpenURL

  10. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, Jones DW, Materson BJ, Oparil S, Wright JT Jr, Roccella EJ: Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. National Heart, Lung, and Blood Institute; National High Blood Pressure Education Program Coordinating Committee. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.

    Hypertension 2003, 42:1206-52. PubMed Abstract | Publisher Full Text OpenURL

  11. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus

    Diabetes Care 1997, 20:1183-97. PubMed Abstract OpenURL

  12. Pignoli P, Tremoli E, Poli A, Oreste P, Paoletti R: Intimal plus medial thickness of the arterial wall: A direct measurement with ultrasound imaging.

    Circulation 1986, 74:1399-406. PubMed Abstract | Publisher Full Text OpenURL

  13. Post WS, Hill MN, Dennison CR, Weiss JL, Gerstenblith G, Blumenthal RS: High prevalence of target organ damage in young, African American inner-city men with hypertension.

    J Clin Hypertens (Greenwich) 2003, 5:24-30. Publisher Full Text OpenURL

  14. Addo J, Smeeth L, Leon DA: Hypertensive target organ damage in Ghanaian civil servants with hypertension.

    PLoS One 2009, 4:e6672. PubMed Abstract | Publisher Full Text | PubMed Central Full Text OpenURL

  15. Ayodele OE, Alebiosu CO, Salako BL, Awoden OG, Abigun AD: Target organ damage and associated clinical conditions among Nigerians with treated hypertension.

    Cardiovasc J S Afr 2005, 16:89-93. PubMed Abstract | Publisher Full Text OpenURL

  16. Ayodele OE, Alebiosu CO, Akinwusi PO, Akinsola A, Mejiuni A: Target organ damage and associated clinical conditions in newly diagnosed hypertensives attending a tertiary health facility.

    Niger J Clin Pract 2007, 10:319-25. PubMed Abstract OpenURL

  17. Peer N, Steyn K, Dennison CR, Levitt NS, Nyo MT, Nel JH, Commerford PJ, Fourie JM, Hill MN: Determinants of target organ damage in black hypertensive patients attending primary health care services in Cape Town: the Hi-Hi study.

    Am J Hypertens 2008, 21:896-902. PubMed Abstract | Publisher Full Text OpenURL

  18. Cuspidi C, Valerio C, Sala C, Esposito A, Masaidi M, Negri F, Zanchetti A, Mancia G: Prevalence and correlates of multiple organ damage in a never-treated hypertensive population: role of ambulatory blood pressure.

    Blood Press Monit 2008, 13:7-13. PubMed Abstract | Publisher Full Text OpenURL

  19. Cea-Calvo L, Conthe P, Gómez-Fernández P, de Alvaro F, Fernández-Pérez C, RICARHD investigators: Target organ damage and cardiovascular complications in patients with hypertension and type 2 diabetes in Spain: a cross-sectional study.

    Cardiovasc Diabetol 2006, 5:23. PubMed Abstract | BioMed Central Full Text | PubMed Central Full Text OpenURL

  20. Salako BL, Ogah OS, Adebiyi AA, Adedapo KS, Bekibele CO, Oluleye TS, Okpechi I: Unexpectedly high prevalence of target-organ damage in newly diagnosed Nigerians with hypertension.

    Cardiovasc J Afr 2007, 18:77-83. PubMed Abstract | Publisher Full Text OpenURL

  21. Kotsis V, Stabouli S, Toumanidis S, Papamichael C, Lekakis J, Germanidis G, Hatzitolios A, Rizos Z, Sion M, Zakopoulos N: Target organ damage in "white coat hypertension" and "masked hypertension".

    Am J Hypertens 2008, 21:393-9. PubMed Abstract | Publisher Full Text OpenURL

  22. Cuspidi C, Meani S, Valerio C, Sala C, Fusi V, Zanchetti A, Mancia G: Age and target organ damage in essential hypertension: role of the metabolic syndrome.

    Am J Hypertens 2007, 20:296-303. PubMed Abstract | Publisher Full Text OpenURL

  23. Cuspidi C, Valerio C, Giudici V, Negri F, Sala C, Zanchetti A, Mancia G: Metabolic syndrome and multiple organ damage in essential hypertension.

    Blood Press 2008, 17:195-203. PubMed Abstract | Publisher Full Text OpenURL

  24. Navarro J, Redón J, Cea-Calvo L, Lozano JV, Fernández-Pérez C, Bonet A, González-Esteban J: Metabolic syndrome, organ damage and cardiovascular disease in treated hypertensive patients. The ERIC-HTA study.

    Blood Press 2007, 16:20-7. PubMed Abstract | Publisher Full Text OpenURL

  25. Lozano JV, Redon J, Cea-Calvo L, Fernandez-Perez C, Navarro J, Bonet A, Gonzalez-Esteban J: Left ventricular hypertrophy in the Spanish hypertensive population. The ERIC-HTA study.

    Rev Esp Cardiol 2006, 59:136-42. PubMed Abstract | Publisher Full Text OpenURL

  26. Mule G, Nardi E, Cottone S, Cusimano P, Volpe V, Piazza G, Mongiovi R, Mezzatesta G, Andronico G, Cerasola G: Influence of metabolic syndrome on hypertension-related target organ damage.

    J Intern Med 2005, 257:503-13. PubMed Abstract | Publisher Full Text OpenURL

Pre-publication history

The pre-publication history for this paper can be accessed here:

http://www.biomedcentral.com/1471-2296/12/75/prepub