Family Practice Advance Access originally published online on March 29, 2007
Family Practice 2007 24(3):259-262; doi:10.1093/fampra/cmm005
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Pilot study of potential barriers to blood pressure control in patients with inadequately controlled hypertension
a Department of Community Health Sciences, St George's, University of London, London, UK
b Clinical Sciences Research Institute, Warwick Medical School, Coventry, UK. Correspondence to: Sally C. Dean, Department of Community Health Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK. Email: sally.dean@sgul.ac.uk
Received 23 December 2005; Revised 21 December 2006; Accepted 1 February 2004.
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Abstract |
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Background. Most people with high blood pressure (BP) are managed in primary care, but BP control is often inadequate.
Objectives. To examine potential barriers to adequate BP control in patients with poorly controlled hypertension.
Design. Cross-sectional survey.
Setting. Computerized inner city general practice.
Participants. A total of 155 hypertensive patients aged 50–80 years with last recorded BP 
150/90 mm Hg (or 140/85 mm Hg if diabetic).
Methods. Patients were invited to attend a nurse-led clinic where BP was measured according to a standardized protocol and patients were asked to complete a semi-structured questionnaire including lifestyle, compliance with treatment and knowledge about hypertension. Details of BP reviews were obtained from medical records.
Results. A total of 110 patients (71%) with a mean age of 65 years attended the nurse-led clinic of whom 27% were of African origin. Of those who attended, 52 (47%) had adequately controlled BP when measured according to protocol. The remaining 58 (53%) had inadequately controlled BP. Of patients on treatment, 94% (83/88) reported taking it at least 6 days a week. Only 9% of patients knew their target BP and only 39% that treatment aims to prevent stroke or heart attack. Patients with diabetes were more likely than those without to have BP audit standard (79% 26/33 versus 42% 32/77, P < 0.001).
Conclusion. About half of apparently uncontrolled hypertensive patients had BP below target when measured according to standard methods. Reported compliance was good, but patient knowledge of target BP was poor. Patients with diabetes were more likely than those without to have inadequately controlled BP.
Keywords. Blood pressure control, primary care, barriers.
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Introduction |
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Rigorous adherence to blood pressure (BP) treatment guidelines has been shown to improve BP control and reduce cardiovascular mortality1. In the UK, most hypertensives are managed in primary care but BP control is often inadequate2. This may be due to patient-related, health professional-related or organizational factors including poor compliance, ‘clinical inertia'—reluctance to change treatment despite failure to achieve target BP and lack of regular review3,4. We used data from patient questionnaires, clinical examination and medical records to examine potential barriers to adequate BP control in patients in primary care. As we planned to develop and pilot an intervention to improve BP control, we focused on patients with inadequately controlled hypertension according to the medical records.
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Methods |
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In January–March 2004, we conducted a cross-sectional survey in a multi-ethnic, inner city London general practice with 9000 patients. We performed a computerized search to identify patients on the hypertension register (read code G2 hypertensive disease) aged 50–80 years with last recorded BP
British Hypertension Society (BHS) audit standard in use at that time (150/90 mm Hg or 140/85 mm Hg if diabetic)5. Following exclusions of patients who were housebound or had severe illness, a letter and information sheet were sent asking patients to attend a nurse-led BP clinic at the practice. Patients who attended were seen by the research nurse (SD) and written informed consent was obtained. BP was measured using the Omron HEM-705CP according to the BHS protocol5. This involves measuring BP three times with the patient appropriately positioned, using a suitably sized cuff and averaging the last two readings. Patients were asked to complete a semi-structured questionnaire on demography, medical history, lifestyle, compliance with treatment and knowledge about hypertension.
Statistical analysis was performed using SPSS (version 12.0). We compared characteristics of attenders with non-attenders using chi-square tests. As BP targets are lower for people with diabetes, we compared BP control in those with and without diabetes.
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Results |
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From the hypertension register (n = 356), 225 (63%) patients were identified with a latest recorded BP
audit standard of whom 155 were eligible and invited to take part. The response rate was 71% (n = 110). The mean age of responders was 65 years, 27% were Black African or Black Caribbean and 30% had diabetes (Table 1). Baseline characteristics including age, ethnicity and most recent recorded BP were similar in attenders and non-attenders (Table 1).
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BP control in the clinic
In the 110 hypertensive patients who attended, mean BP in the clinic was 147/83 (SD 18/10) mm Hg. Nearly half (n = 52, 47%) had BP below audit standard when measured according to protocol. The remaining 58 (53%) had inadequately controlled BP, of whom 69% (40/58) had had their BP checked in the surgery at least twice in the past year. Patients with diabetes were more likely than those without to have BP
audit standard (79% 26/33 versus 42% 32/77, P < 0.001).
Compliance with treatment and knowledge about BP
Twenty-two (20%) patients were not prescribed anti-hypertensive medication. Most patients on treatment (n = 83/88 94%) said they took their anti-hypertensive medication on 6 days per week or more. However, 34 (39%) said they occasionally missed or forgot their medication. This was due to running out of drugs (n = 7), being unsure if taken already (n = 5), no particular reason (n = 5), busy routine (n = 4), change of routine (n = 4), feeling well (n = 4), taking too many drugs (n = 2), different moods (n = 2), or feeling unwell (n = 1). Only 2/88 (2%) patients were not currently taking their prescribed medication. Overall, 9% (10/110) of patients knew their target BP and 39% that treatment aims to prevent stroke or heart attack. Home BP monitoring was performed by 15% of patients.
Health care professional and organization (n = 110)
Seventy-two (65%) patients had their BP reviewed at least twice in the preceding 12 months by a health professional. Possible barriers to BP control according to the medical records included health professional under-prescribing or feels BP satisfactory despite being persistently above target (47%), BP under review (23%), health professional omitted to recheck BP at subsequent appointments (10%), patient missed BP review (7%), health professional (5%) or practice (5%) did not organize further follow-up, or patient not taking prescribed medication (2%).
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Discussion |
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Principal findings
About half of apparently uncontrolled hypertensive patients had BP below target when measured according to standard methods. Reported compliance with treatment was high but patient knowledge of target BP was poor. Patients with diabetes were more likely than those without to have inadequately controlled BP.
Strengths and weaknesses
To our knowledge, this is the first UK study examining barriers to BP control in an inner city practice. A quarter of participants were of African origin, a group at increased risk of hypertension and stroke. The study may be relevant to similar populations in other countries. The response rate was high and 100% completion of questionnaires was obtained. The limitations are the size of the study and that we do not know if the improvement in BP control in those who attended the clinic was due to regression to the mean or measuring BP correctly. It is likely that the GPs and practice nurses did not routinely measure BP according to the BHS protocol; however, we were unable to assess this objectively. As we excluded patients with last recorded BP < audit standard, we did not sample all hypertensive patients. The prevalence of diagnosed hypertension in this practice was below the national average (6% versus 11%). Possible reasons include young population, under-diagnosis or inaccurate register. Finally, we were unable to obtain objective measurements of patient compliance or to assess the attitudes of the GPs and nurses.
Implications for clinical practice and research
Researchers planning studies of people with hypertension should be aware that around half of apparently uncontrolled hypertensives may have BP below target when remeasured under research conditions. This may affect sample size calculations. We also found that less than 10% of patients knew their target BP. This should be explained and BP documented at each visit on patient-held records2. Time should be taken to measure BP accurately according to guidelines6, and BP persistently above target should be controlled using a step-wise treatment protocol and combination therapy2.
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Declaration |
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Funding: This study was supported by grants from the Burdett Trust for Nursing and Starnet London.
Ethical approval: Wandsworth Local Research Ethics Committee reference 02.42.2.
Conflicts of interest: None.
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Acknowledgments |
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We are grateful to staff and patients at the Clapham Manor Health Centre, London, who kindly agreed to participate in this study.
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Notes |
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Dean SC, Kerry SM, Cappuccio FP, Oakeshott P. Pilot study of potential barriers to blood pressure control in patients with inadequately controlled hypertension. Family Practice 2007; 24: 259–262.
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References |
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1 Fahey T, Schroeder K, Ebrahim S. Interventions used to improve control of blood pressure in patients with hypertension. Cochrane Database Syst Rev. 2006, Issue 4, Article no.: CD005182 (doi: 10.1002/14651858. CD005182. pub3.
2 Williams B, Poulter NR, Brown MJ, et al. Guidelines for management of hypertension: report of the fourth working party of the British Hypertension Society, 2004-BHS IV. J Hum Hypertens (2004) 18:139–185.[CrossRef][Web of Science][Medline]
3 Oliveria SA, Lapuerta P, McCarthy BD, L'Italien GJ, Berlowitz DR, Asch SM. Physician-related barriers to the effective management of uncontrolled hypertension. Arch Intern Med (2002) 162:413–420.
4 Inkster M, Montgomery A, Donnan P, MacDonald T, Sullivan F, Fahey T. Organisation factors in relation to control of blood pressure: an observational study. Br J Gen Pract (2005) 55:931–937.[Web of Science][Medline]
5 Ramsay L, Williams B, Johnston G, et al. Guidelines for management of hypertension: report of the third working party of the British Hypertension Society. J Hum Hypertens (1999) 13:569–592.[CrossRef][Web of Science][Medline]
6 Parati G, Bilo G, Mancia G. Blood pressure measurement in research and in clinical practice: recent evidence. Curr Opin Nephrol Hypertens (2004) 13:343–357.[CrossRef][Web of Science][Medline]
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