Static outliers for Wb 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 Wb PCN is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Mepivacaine hydrochloride	55	Local anaesthetics	205	0.27	0.00	0.01	21.66
Scandonest plain 3% solution for injection 2.2ml cartridges : 55
Magnesium hydroxide	3	Antacids and simeticone	3	1.00	0.03	0.11	8.93
Phillips' Milk of Magnesia 415mg/5ml oral suspension : 3
Betaxolol	46	Treatment of glaucoma	2149	0.02	0.00	0.00	7.93
Betaxolol 0.5% eye drops : 13 Betaxolol 0.25% eye drops 0.25ml unit dose preservative free : 8 Betoptic 0.5% eye drops : 15 Betoptic 0.25% suspension eye drops : 2 Betoptic 0.25% eye drops suspension 0.25ml unit dose : 8
Other magnesium preparations	5	Magnesium	15	0.33	0.01	0.05	6.22
Valupak Magnesium tablets : 5
Denosumab	102	Bisphosphonates and other drugs	1018	0.10	0.01	0.02	4.68
Denosumab 60mg/1ml inj pre-filled syringes : 64 Prolia 60mg/1ml solution for injection pre-filled syringes : 38

Prescribing where Wb PCN is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Lidocaine hydrochloride	132	Local anaesthetics	205	0.64	0.91	0.07	-3.74
Lidocaine 50mg/5ml (1%) solution for injection ampoules : 1 Lidocaine 20mg/2ml (1%) solution for injection ampoules : 12 Lidocaine 100mg/5ml (2%) solution for injection ampoules : 1 Lidocaine 5% medicated plasters : 29 Xylocaine 1% with Adrenaline 100microg/20ml inj vials : 50 Instillagel gel : 12 Emla 5% cream : 26 Ralvo 700mg medicated plasters : 1
Zinc oxide	4	Soothing haemorrhoidal preparations	11	0.36	0.77	0.14	-2.90
Anusol cream : 4
Apixaban	358	Oral anticoagulants	2925	0.12	0.40	0.12	-2.28
Apixaban 2.5mg tablets : 192 Apixaban 5mg tablets : 166
Solifenacin	126	Drugs for urinary frequency enuresis and incontinence	845	0.15	0.33	0.08	-2.18
Solifenacin 5mg tablets : 87 Solifenacin 10mg tablets : 36 Vesicare 5mg tablets : 3
Ganciclovir	0	Antivirals	2	0.00	0.70	0.34	-2.06