Static outliers for Nook Surgery

There is substantial variation in prescribing behaviours, across various different areas of medicine. Some variation can be explained by demographic changes, or local policies or guidelines, but much of the remaining variation is less easy to explain. At OpenPrescribing we are piloting a number of data-driven approaches to identify unusual prescribing and collect feedback on this prescribing to inform development of new tools to support prescribers and organisations to audit and review prescribing.

This report has been developed to automatically identify prescribing patterns at a chemical level which are furthest away from “typical prescribing” and can be classified as an “outlier”. We calculate the number of prescriptions for each chemical in the BNF coding system using the BNF subparagraph as a denominator, for prescriptions dispensed between April 2021 and August 2021. We then calculate the mean and standard deviation for each numerator and denominator pair across all practices/CCGs/PCNs/STPs. From this we can calculate the “z-score”, which is a measure of how many standard deviations a given practice/CCG/PCN/STP is from the population mean. We then rank your “z-scores” to find the top 5 results where prescribing is an outlier for prescribing higher than its peers and those where it is an outlier for prescribing lower than its peers.

It is important to remember that this information was generated automatically and it is therefore likely that some of the behaviour is warranted. This report seeks only to collect information about where this variation may be warranted and where it might not. Our full analytical method code is openly available on GitHub here.

The DataLab is keen to hear your feedback on the results. You can do this by completing the following survey or emailing us at ebmdatalab@phc.ox.ac.uk. Please DO NOT INCLUDE IDENTIFIABLE PATIENT information in your feedback. All feedback is helpful, you can send short or detailed feedback.

Prescribing where Nook Surgery is higher than most

BNF Chemical Chemical Items BNF Subparagraph Subparagraph Items Ratio Mean std Z_Score Plots
Co-fluampicil(Flucloxacillin/ampicillin) 2 Broad-spectrum penicillins 112 0.02 0.00 0.00 11.62
Acetazolamide 27 Treatment of glaucoma 125 0.22 0.01 0.02 10.72
Ropinirole hydrochloride 88 Dopaminergic drugs used in parkinsonism 98 0.90 0.15 0.12 6.37
Tamsulosin and dutasteride hydrochloride 46 Drugs for urinary retention 223 0.21 0.02 0.03 5.94
Cyclizine lactate 14 Drugs used in nausea and vertigo 132 0.11 0.01 0.02 5.70

Prescribing where Nook Surgery is lower than most

BNF Chemical Chemical Items BNF Subparagraph Subparagraph Items Ratio Mean std Z_Score Plots
Gliclazide 106 Sulfonylureas 297 0.36 0.92 0.14 -4.19
Tamsulosin hydrochloride 168 Drugs for urinary retention 223 0.75 0.92 0.06 -2.71
Diazepam 48 Anxiolytics 109 0.44 0.75 0.14 -2.31
Oral rehydration salts 1 Oral sodium and water 22 0.05 0.68 0.31 -2.06
Mebeverine hydrochloride 16 Antispasmodic and other drugs altering gut motility 84 0.19 0.45 0.13 -2.04