Skip to contents

Blood Pressure Assessment Functions for Paediatric and Adult Populations

Source: R/bp_family.R
bp_family.Rd

This module provides functions to assess blood pressure (BP) in children, young people, and adults using age-appropriate clinical guidelines, currently the package uses:

  • Children/adolescents (0-17 years): NHBPEP Fourth Report

  • Young adults (>17 years): NICE/BHF guidelines

Details

The functions implement clinical BP categorisation following:

  • NHBPEP Fourth Report: Sex-, age-, and height-specific percentiles for paediatric BP

  • NICE/BHF Guidelines: Fixed thresholds for adult hypertension stages

  • NPDA Limits: National Paediatric Diabetes Audit validity ranges (50/15-200/150 mmHg)

  • NDA Limits: National Diabetes Audit validity ranges (70/20-300/150 mmHg)

BP Categories by Age Group

CategoryAge (years)ReferenceCriteria
Normotension[0-12] (children)NHBPEP Fourth Report (NPDA min)(50/15mmHg \(\leq\)) SBP/DBP < 90th percentile
Normotension(12-17] (adolescents)NHBPEP Fourth Report (NPDA min)(50/15mmHg \(\leq\)) SBP/DBP < 120/80 mmHg
Normotension>17NICE/BHF (NDA min)(70/20mmHg \(\leq\)) SBP/DBP < 120/80 mmHg
Prehypertension[0-12] (children)NHBPEP Fourth Report90th \(\leq\) SBP/DBP < 95th
Prehypertension(12-17] (adolescents)NHBPEP Fourth Report120/80mmHg \(\leq\) SBP/DBP < 95th
Prehypertension>17NICE/BHF120/80mmHg \(\leq\) SBP/DBP < 140/90mmHg
Stage 1 hypertension[0-1) (newborns)NHBPEP Fourth Report95th \(\leq\) SBP < 5mmg above 99th
Stage 1 hypertension[1-17]NHBPEP Fourth Report95th \(\leq\) SBP/DBP < 5mmg above 99th
Stage 1 hypertension>17NICE/BHF140/90mmHg \(\leq\) SBP/DBP < 160/100mmHg
Stage 2 hypertension[0-1) (newborns)NHBPEP Fourth Report (NPDA max)5mmg above 99th \(\leq\) SBP (\(\leq\) 200/150mmHg)
Stage 2 hypertension[1-17]NHBPEP Fourth Report (NPDA max)5mmg above 99th \(\leq\) SBP/DBP (\(\leq\) 200/150mmHg)
Stage 2 hypertension>17NICE/BHF160/100mmHg \(\leq\) SBP/DBP < 180/120mmHg
Stage 3 hypertension>17NICE/BHF (NDA max)180/120mmHg \(\leq\) SBP/DBP (\(\leq\) 300/150mmHg)

Height Reference Standards for the Fourth Report

Fourth Report Regression Model:

The Fourth Report uses regression models with age (centred at 10 years) and height z-score polynomial terms (up to 4th degree) to calculate expected BP:

$$\mu = \alpha + \sum_{j=1}^{4} \beta_j (Age-10)^j + \sum_{k=1}^{4} \gamma_k (Z_{ht})^k$$

BMI References:

The Fourth Report was developed and validated using US CDC 2000 growth references for height percentiles. Your height z-scores should ideally be based on US CDC reference. However, UK clinical practice and NPDA audit analysis use UK-WHO growth charts as standard (historically the NPDA used the British 1990), so using the UK-WHO is also considered acceptable in UK contexts (based on the assumption that the two populations are similar enough).

To our knowledge, the Fourth Report BP percentiles have not been validated using UK-WHO height references. The clinical impact of applying Fourth Report regression coefficients with UK-WHO (rather than US CDC) height z-scores has not been formally evaluated. Users should be aware of this methodological discrepancy when interpreting results or comparing to US-based implementations.

Calculating Height Z-Scores:

This package requires height z-scores as input and does not calculate them internally. Two approaches I recommended for obtaining height z-scores are:

  1. childsds R package (https://mvogel78.r-universe.dev/childsds), which provides SDS/z-score calculations based on multiple growth standards (including UK–WHO, US CDC references).

  2. RCPCHGrowth Python library (https://growth.rcpch.ac.uk/products/python-library/), which is the official RCPCH implementation of UK-WHO growth charts, with API accessible from R.

References

See also

Other BP functions: .bp_message(), .bp_resolve_limit(), .bp_validate_demo_input(), bp_assess(), bp_category(), bp_expected(), bp_relative()