Static outliers for Orwell PCN

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 Orwell PCN is higher than most

BNF Chemical Chemical Items BNF Subparagraph Subparagraph Items Ratio Mean std Z_Score Plots
Potassium bicarbonate 2 Oral bicarbonate 46 0.04 0.00 0.00 26.55
Etodolac 336 Non-steroidal anti-inflammatory drugs 2838 0.12 0.01 0.01 9.61
Ibrutinib 1 Other antineoplastic drugs 43 0.02 0.00 0.00 7.96
Antazoline 9 Other anti-inflammatory preparations 102 0.09 0.01 0.01 6.38
Hydrocort sodiumphos 28 Antibacterials 211 0.13 0.01 0.02 6.00

Prescribing where Orwell PCN is lower than most

BNF Chemical Chemical Items BNF Subparagraph Subparagraph Items Ratio Mean std Z_Score Plots
Sodium bicarbonate 44 Oral bicarbonate 46 0.96 1.00 0.00 -26.55
Tiotropium bromide 99 Antimuscarinic bronchodilators 632 0.16 0.71 0.15 -3.74
Cetirizine hydrochloride 130 Antihistamines 1848 0.07 0.28 0.08 -2.68
Isosorbide mononitrate 625 Nitrates 1099 0.57 0.73 0.07 -2.44
Isosorbide mononitrate 10mg tablets : 66
Isosorbide mononitrate 20mg tablets : 17
Isosorbide mononitrate 40mg tablets : 7
Isosorbide mononitrate 60mg modified-release tablets : 24
Isosorbide mononitrate 50mg modified-release capsules : 6
Isosorbide mononitrate 40mg modified-release tablets : 8
Isosorbide mononitrate 25mg modified-release capsules : 50
Isosorbide mononitrate 40mg modified-release capsules : 17
Isosorbide mononitrate 60mg modified-release capsules : 5
Isosorbide mononitrate 25mg modified-release tablets : 4
Isosorbide mononitrate 20mg/5ml oral suspension : 5
Elantan LA50 capsules : 39
Elantan LA25 capsules : 83
Modisal XL 40mg tablets : 2
Imdur 60mg modified-release tablets : 10
Monomax XL 60mg tablets : 31
Monomil XL 60mg tablets : 236
Nyzamac SR 40mg capsules : 10
Nyzamac SR 60mg capsules : 5
Simple 2 Expectorant and demulcent cough preparations 3 0.67 0.96 0.13 -2.33