Static outliers for The Westgate Practice

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 The Westgate Practice is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Ciprofloxain/dexameth☰	121	Otitis externa	326	0.37	0.05	0.06	5.14
Ciprofloxacin 0.3% / Dexamethasone 0.1% ear drops : 120 Cilodex ear drops : 1
Pilocarpine nitrate☰	38	Treatment of glaucoma	3100	0.01	0.00	0.00	4.10
Pilocarpine nitrate 2% eye dps 0.5ml ud preservative free : 34 Minims pilocarpine nitrate 2% eye drops 0.5ml unit dose : 4
Bempedoic acid☰	6	Lipid-regulating drugs	16071	0.00	0.00	0.00	4.01
Bempedoic acid 180mg tablets : 6
Insulin glulisine☰	168	Short-acting insulins	749	0.22	0.03	0.05	3.54
Apidra 100units/ml inj 3ml pre-filled SoloStar pens : 157 Apidra 100units/ml solution for injection 3ml cartridges : 6 Apidra 100units/ml solution for injection 10ml vials : 5
Mercaptamine☰	8	Drugs used in metabolic disorders	9	0.89	0.07	0.25	3.22
Cystagon 50mg capsules : 4 Cystagon 150mg capsules : 4

Prescribing where The Westgate Practice is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Zinc sulfate monohydrate☰	0	Zinc	2	0.00	0.73	0.40	-1.84
Sodium chloride☰	4	Topical nasal decongestants	82	0.05	0.54	0.31	-1.57
Saline Steripoules nebuliser liquid 2.5ml unit dose ampoules : 1 Sodium chloride 0.9% neb liq 2.5ml unit dose ampoules : 3
Dexamethasone☰	191	Otitis externa	326	0.59	0.78	0.13	-1.49
Otomize ear spray : 191
Lithium carbonate☰	38	Drugs used for mania and hypomania	185	0.21	0.61	0.28	-1.45
Priadel 200mg modified-release tablets : 8 Priadel 400mg modified-release tablets : 20 Lithium carbonate 400mg modified-release tablets : 5 Lithium carbonate 200mg modified-release tablets : 5
Sildenafil (Erectile Dysfunction)☰	618	Drugs for erectile dysfunction	963	0.64	0.77	0.09	-1.34
Sildenafil 50mg tablets : 245 Sildenafil 100mg tablets : 359 Sildenafil 25mg tablets : 14