The prevalence of treatment resistant hypertension with consideration of pseudo-resistance and morbidity.

Conference: 
SAPC ASM 2018 - London
Talk Code: 
P1.42
Presenter: 
Peter Hayes
Co-authors: 
Monica Casey, Liam G Glynn, Gerard J Molloy, Hannah Durand, Eoin O’ Brien, Eamon Dolan, John Newell, Andrew W Murphy.
Author institutions: 
Discipline of General Practice, School of Medicine, National University of Ireland, Galway, Ireland , Graduate-entry Medical School, University of Limerick, Limerick, Ireland, School of Psychology, NUI Galway, Ireland, The Conway Institute, University College Dublin, Dublin, Ireland, Connolly Hospital, Blanchardstown, Dublin, Ireland, HRB Clinical Research Facility, NUI Galway, Ireland.

Problem

To confirm treatment resistant hypertension (TRH), ambulatory blood pressure measurement (ABPM) must exclude white coat hypertension (WCH), three or more medications should be prescribed at the optimal doses tolerated, and non-adherence and lifestyle should be examined. Most previous studies have not adequately considered these cardinal features of pseudo-resistance and provide an apparent TRH prevalence figure- which may overestimate the size of the problem.

Approach

We conducted a cross sectional study of the prevalence of apparent TRH in general practice, utilizing the appropriate definition, and then considered pseudo-resistance and morbidity.Forty university-research affiliated practices were invited to participate. With support, each practice ran an anatomical therapeutic chemical (ATC) drug search identifying patients on any possible hypertensive medications and then a search of individual patient’s electronic records took place. ABPM was used to rule out WCH. The World Health Organisation-Defined Daily Dosing guidelines determined adequate dosing. Adherence was defined as whether patients requested nine or more repeat monthly prescriptions within the last year.

Findings

Sixteen practices participated (n=50, 878), and 646 patients had apparent TRH. Dosing was adequate in 19% of patients and 80% were adherent to medications. Using a BP cut-off of 140/90 mm Hg the prevalence of apparent TRH was 9% (95%CI 9.0-10.0). Using 130/80 mm Hg for patients with diabetes or chronic kidney disease, it was 10.0% (95%CI 9.0-11.0). Consideration of all the cardinal features of pseudo-resistance reduced prevalence rates further to 3% (95%CI 3.0-4.0).

Consequences

Reviewing individual patient records results in a lower estimate of prevalence of TRH than has been previously reported. Further consideration for individual patients of pseudo-resistance, additionally lowers these estimates, and may be all that is required for management in the vast majority of cases.

Submitted by: 
Peter Hayes
Funding acknowledgement: 
HRB - Ireland