Static outliers for Underwood 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 Underwood Surgery is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Dextromethorphan hydrobromide☰	4	Cough suppressants	5	0.80	0.01	0.06	12.69
Dextromethorphan 7.5mg/5ml oral solution sugar free : 1 Robitussin Dry Cough 7.5mg/5ml oral solution sugar free : 3
Clemastine fumarate☰	3	Antihistamines	624	0.00	0.00	0.00	9.57
Clemastine 1mg tablets : 3
Methylcellulose☰	4	Bulk-forming laxatives	65	0.06	0.00	0.01	8.75
Methylcellulose 500mg tablets : 1 Celevac 500mg tablets : 3
Liothyronine sodium☰	34	Thyroid hormones	1517	0.02	0.00	0.00	7.42
Liothyronine 20microgram tablets : 34
Promethazine teoclate☰	24	Drugs used in nausea and vertigo	251	0.10	0.00	0.01	6.26
Promethazine teoclate 25mg tablets : 24

Prescribing where Underwood Surgery is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Levothyroxine sodium☰	1483	Thyroid hormones	1517	0.98	1.00	0.00	-7.18
Levothyroxine sodium 25microgram tablets : 401 Levothyroxine sodium 50microgram tablets : 501 Levothyroxine sodium 100microgram tablets : 557 Levothyroxine sodium 75microgram tablets : 17 Levothyroxine sodium 12.5microgram tablets : 7
Cabergoline☰	0	Bromocriptine and other dopaminergic drugs	6	0.00	0.86	0.27	-3.16
Benzydamine hydrochloride☰	3	Drugs for oral ulceration and inflammation	10	0.30	0.83	0.18	-2.84
Difflam 0.15% spray : 2 Benzydamine 0.15% oromucosal spray sugar free : 1
Famotidine☰	6	H2-Receptor antagonists	30	0.20	0.78	0.23	-2.48
Famotidine 40mg tablets : 1 Famotidine 20mg tablets : 5
Codeine phosphate☰	0	Cough suppressants	5	0.00	0.76	0.35	-2.18