Evaluation of a complex intervention to improve primary care prescribing: a phase IV segmented regression interrupted time series analysis

Sean MacBride-Stewart, Charis Marwick, Neil Houston, Iain Watt, Andrea Patton, Bruce Guthrie (Lead / Corresponding author)

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    13 Citations (Scopus)
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    Background: It is uncertain whether improvements in primary care high-risk prescribing seen in research trials can be realised in the real-world setting.

    Aim: To evaluate the impact of a 1-year system-wide phase IV prescribing safety improvement initiative, which included education, feedback, support to identify patients to review, and small financial incentives.

    Design and setting: An interrupted time series analysis of targeted high-risk prescribing in all 56 general practices in NHS Forth Valley, Scotland, was performed. In 2013–2014, this focused on high-risk non-steroidal anti-inflammatory drugs (NSAIDs) in older people and NSAIDs with oral anticoagulants; in 2014–2015, it focused on antipsychotics in older people.

    Method: The primary analysis used segmented regression analysis to estimate impact at the end of the intervention, and 12 months later. The secondary analysis used difference-in-difference methods to compare Forth Valley changes with those in NHS Greater Glasgow and Clyde (GGC).

    Results: In the primary analysis, downward trends for all three NSAID measures that were existent before the intervention statistically significantly steepened following implementation of the intervention. At the end of the intervention period, 1221 fewer patients than expected were prescribed a high-risk NSAID. In contrast, antipsychotic prescribing in older people increased slowly over time, with no intervention-associated change. In the secondary analysis, reductions at the end of the intervention period in all three NSAID measures were statistically significantly greater in NHS Forth Valley than in NHS GGC, but only significantly greater for two of these measures 12 months after the intervention finished.
    Original languageEnglish
    Pages (from-to)e352-e360
    Number of pages9
    JournalBritish Journal of General Practice
    Issue number658
    Early online date27 Apr 2017
    Publication statusPublished - May 2017


    • Antipsychotic drugs
    • General practice
    • High-risk prescribing
    • Interrupted time series analysis
    • Non-steroidal anti-inflammatory drugs
    • Quality improvement

    ASJC Scopus subject areas

    • Family Practice


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