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

Abstract

Background
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.

Methods
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.

Results
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 

Citation

Parker, R. A., Padfield, P., Hanley, J., Pinnock, H., Kennedy, J., Stoddart, A., Hammersley, V., Sheikh, A., & McKinstry, B. (2021). Examining the effectiveness of telemonitoring with routinely acquired blood pressure data in primary care: challenges in the statistical analysis. BMC Medical Research Methodology, 21(1), Article 31 (2021). https://doi.org/10.1186/s12874-021-01219-8

• 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)
• DOI: https://doi.org/10.1186/s12874-021-01219-8
• Keywords: Routine data, Implementation study, Quasi-experimental, Telemonitoring, Blood pressure control, Hypertension, End digit preference
• Public URL: http://researchrepository.napier.ac.uk/Output/2745047