Static outliers for Carshalton 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 Carshalton PCN is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Other topical corticosteroid preparations☰	14	Topical corticosteroids	3779	0.00	0.00	0.00	17.69
Propylene glycol 40% in Clobetasol 0.05% cream : 14
Metformin hydrochloride/sitagliptin☰	704	Other antidiabetic drugs	7070	0.10	0.01	0.01	6.22
Metformin 1g / Sitagliptin 50mg tablets : 663 Janumet 50mg/1000mg tablets : 41
Iron and folic acid☰	54	Oral iron	3362	0.02	0.00	0.00	5.08
Ferrous fumarate 322mg / Folic acid 350microgram tablets : 2 Ferrograd Folic 325mg/350microgram modified-release tablets : 41 Pregaday 322mg/350microgram tablets : 11
Dienogest☰	7	Progestogens and progesterone receptor modulators	309	0.02	0.00	0.00	4.45
Dienogest 2mg tablets : 7
Norethisterone☰	145	Oral progestogen-only contraceptives	1124	0.13	0.05	0.02	3.43
Norethisterone 350microgram tablets : 111 Noriday 350microgram tablets : 34

Prescribing where Carshalton PCN is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Desogestrel☰	959	Oral progestogen-only contraceptives	1124	0.85	0.94	0.03	-3.29
Desogestrel 75microgram tablets : 859 Cerazette 75microgram tablets : 39 Cerelle 75microgram tablets : 52 Zelleta 75microgram tablets : 3 Feanolla 75microgram tablets : 6
Theophylline☰	128	Theophylline	308	0.42	0.84	0.15	-2.85
Theophylline 200mg modified-release tablets : 17 Uniphyllin Continus 400mg tablets : 4 Uniphyllin Continus 200mg tablets : 84 Uniphyllin Continus 300mg tablets : 23
Duloxetine hydrochloride☰	268	Other antidepressant drugs	6688	0.04	0.15	0.05	-2.18
Duloxetine 30mg gastro-resistant capsules : 127 Duloxetine 60mg gastro-resistant capsules : 141
Naftidrofuryl oxalate☰	1	Peripheral vasodilators and related drugs	15	0.07	0.67	0.28	-2.15
Naftidrofuryl 100mg capsules : 1
Azelaic acid☰	11	Topical preparations for acne	592	0.02	0.07	0.03	-1.93
Azelaic acid 20% cream : 3 Azelaic acid 15% gel : 5 Skinoren 20% cream : 3