Predictors of uncontrolled hypertension and antihypertensive medication nonadherence.
BACKGROUND
Although hypertension is, in most cases, a controllable major risk factor in the development of cardiovascular disease, studies have demonstrated that hypertension remains poorly controlled in Portugal. Our aim was to evaluate the covariates associated with poor blood pressure (BP) control in a Portuguese hypertensive population.


RESULTS
We conducted a cross-sectional survey in a hospital hypertension outpatient clinic, located in the Eastern Central Region of Portugal. Patients attending the clinic from July to September 2009 were asked to participate in a structured interview including medication adherence and knowledge about hypertension. Eligible participants were all adults aged 18 or over with an established diagnosis of arterial hypertension and had been on antihypertensive drug treatment for at least 6 months. Exclusion criteria were dementia, pregnancy, and breastfeeding. Detailed clinical information was prospectively obtained from medical records. A total of 197 patients meeting the inclusion criteria and consenting to participate completed the interview. Of these, only 33.0% had their BP controlled according to the JNC 7 guidelines. Logistic regression analysis revealed three independent predictors of poor BP control: living alone (OR = 5.3, P = 0.004), medication nonadherence (OR = 4.8, P < 0.001), and diabetes (OR = 4.4, P = 0.011). Predictors of medication nonadherence were: unawareness of target BP values (OR = 3.7, P < 0.001), a report of drug side effects (OR = 3.7, P = 0.002), lack of BP monitoring (OR = 2.5, P = 0.015) and unawareness of medication indications (OR = 2.4, P = 0.021), and of hypertension risks (OR = 2.1, P = 0.026).


CONCLUSIONS
Poor medication adherence, lack of information about hypertension, and side effects should be considered as possible underlying causes of uncontrolled BP and must be addressed in any intervention aimed to improve BP control.
Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique 6200-506, Portugal.
Manuel
M
Morgado
Sandra
S
Rolo
Ana Filipa
AF
Macedo
Luísa
L
Pereira
Miguel
M
Castelo-Branco
JAMA. 1995 May 10;273(18):1436-8
7723157
J Manag Care Pharm. 2006 May;12(4):303-9
16792436
Am J Public Health. 1983 Feb;73(2):153-62
6849473
J Gen Intern Med. 2005 Mar;20(3):219-25
15836524
J Hypertens. 2007 Jun;25(6):1105-87
17563527
Lancet. 2002 Mar 23;359(9311):995-1003
11937178
JAMA. 2002 Dec 11;288(22):2868-79
12472329
J Am Board Fam Med. 2008 Nov-Dec;21(6):512-21
18988718
Hypertension. 2004 Nov;44(5):602-8
15381676
MedGenMed. 2007 Sep 19;9(3):58
18092064
J Hum Hypertens. 2005 Jul;19(7):577-84
15830000
J Am Soc Hypertens. 2010 Mar-Apr;4(2):90-8
20400053
Med Care. 1986 Jan;24(1):67-74
3945130
Am J Cardiol. 1990 Jun 1;65(20):1384-6
2188495
Hypertension. 2007 Jan;49(1):69-75
17159087
Arch Intern Med. 2004 Apr 12;164(7):722-32
15078641
Arch Intern Med. 2009 Nov 23;169(21):1996-2002
19933962
Hypertension. 2003 Dec;42(6):1206-52
14656957
Curr Opin Cardiol. 2004 Jul;19(4):357-62
15218396
Rev Port Cardiol. 2006 Jun;25(6):649-60
17019982
Rev Port Cardiol. 2007 Jan;26(1):21-39
17427834
Ann Pharmacother. 2008 Feb;42(2):169-76
18182472
J Clin Hypertens (Greenwich). 2002 Nov-Dec;4(6):393-404
12461301
CMAJ. 1999 Jan 12;160(1):41-6
9934342