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Examining the effectiveness of telemonitoring with routinely acquired blood pressure data in primary care: challenges in the statistical analysis

Parker, Richard A.; Padfield, Paul; Hanley, Janet; Pinnock, Hilary; Kennedy, John; Stoddart, Andrew; Hammersley, Vicky; Sheikh, Aziz; McKinstry, Brian


Richard A. Parker

Paul Padfield

Hilary Pinnock

John Kennedy

Andrew Stoddart

Vicky Hammersley

Aziz Sheikh

Brian McKinstry


Scale-up BP was a quasi-experimental implementation study, following a successful randomised controlled trial of the roll-out of telemonitoring in primary care across Lothian, Scotland. Our primary objective was to assess the effect of telemonitoring on blood pressure (BP) control using routinely collected data. Telemonitored systolic and diastolic BP were compared with surgery BP measurements from patients not using telemonitoring (comparator patients). The statistical analysis and interpretation of findings was challenging due to the broad range of biases potentially influencing the results, including differences in the frequency of readings, ‘white coat effect’, end digit preference, and missing data.

Four different statistical methods were employed in order to minimise the impact of these biases on the comparison between telemonitoring and comparator groups. These methods were “standardisation with stratification”, “standardisation with matching”, “regression adjustment for propensity score” and “random coefficient modelling”. The first three methods standardised the groups so that all participants provided exactly two measurements at baseline and 6–12 months follow-up prior to analysis. The fourth analysis used linear mixed modelling based on all available data.

The standardisation with stratification analysis showed a significantly lower systolic BP in telemonitoring patients at 6–12 months follow-up (-4.06, 95% CI -6.30 to -1.82, p 

Journal Article Type Article
Acceptance Date Jan 25, 2021
Online Publication Date Feb 10, 2021
Publication Date 2021-02
Deposit Date Feb 19, 2021
Publicly Available Date Feb 19, 2021
Journal BMC Medical Research Methodology
Publisher BMC
Peer Reviewed Peer Reviewed
Volume 21
Issue 1
Article Number 31 (2021)
Keywords Routine data, Implementation study, Quasi-experimental, Telemonitoring, Blood pressure control, Hypertension, End digit preference
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Examining The Effectiveness Of Telemonitoring With Routinely Acquired Blood Pressure Data In Primary Care: Challenges In The Statistical Analysis (1.2 Mb)

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This article is licensed under a Creative Commons Attribution 4.0 International License.

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