Variation in hypertension clinical practice guidelines: a global comparison.

Background: Hypertension is the largest single contributor to the global burden of disease, affecting an estimated 1.39 billion people worldwide. Clinical practice guidelines (CPGs) can aid in the effective management of this common condition, however, inconsistencies exist between CPGs, and the extent of this is unknown. Understanding the differences in CPG recommendations across income settings may provide an important means of understanding some of the global variations in clinical outcomes related to hypertension.

Aims: This study aims to analyse the variation between hypertension CPGs globally. It aims to assess the variation in three areas: diagnostic threshold and staging, treatment and target blood pressure (BP) recommendations in hypertension.

Methods: A search was conducted on the MEDLINE repository to identify national and international hypertension CPGs from 2010 to May 2020. An additional country-specific grey-literature search was conducted for all countries and territories of the world as identified by the World Bank. Data describing the diagnosis, staging, treatment and target blood pressure were extracted from CPGs, and variations between CPGs for these domains were analysed.

Results: Forty-eight CPGs from across all World Bank income settings were selected for analysis. Ninety-six per cent of guidelines defined hypertension as a clinic-based BP of ≥140/90 mmHg, and 87% of guidelines recommended a target BP of < 140/90 mmHg. In the pharmacological treatment of hypertension, eight different first-step, 17 different second-step and six different third-step drug recommendations were observed. Low-income countries preferentially recommended diuretics (63%) in the first-step treatment, whilst high-income countries offered more choice between antihypertensive classes. Forty-four per cent of guidelines, of which 71% were from higher-income contexts recommended initiating treatment with dual-drug therapy at BP 160/100 mmHg or higher.

Conclusion: This study found that CPGs remained largely consistent in the definition, staging and target BP recommendations for hypertension. Extensive variation was observed in treatment recommendations, particularly for second-line therapy. Variation existed between income settings; low-income countries prescribed cheaper drugs, offered less clinician choice in medications and initiated dual therapy at later stages than higher-income countries. Future research exploring the underlying drivers of this variation may improve outcomes for hypertensive patients across clinical contexts.