Static outliers for St Mary'S 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 St Mary'S Surgery is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Ranitidine hydrochloride	1	H2-Receptor antagonists	1	1.00	0.04	0.12	8.22
Ranitidine 150mg tablets : 1
Alogliptin/metformin	55	Other antidiabetic drugs	417	0.13	0.00	0.02	6.95
Alogliptin 12.5mg / Metformin 1g tablets : 55
Clindamycin/tretinoin	11	Topical preparations for acne	46	0.24	0.02	0.04	5.91
Treclin 1%/0.025% gel : 1 Clindamycin 1% / Tretinoin 0.025% gel : 10
Selenium sulfide	7	Shampoos and some other scalp preparations	24	0.29	0.03	0.05	5.63
Selsun 2.5% shampoo : 1 Selenium sulfide 2.5% shampoo : 6
Naratriptan hydrochloride	19	Treatment of acute migraine	73	0.26	0.04	0.05	4.71
Naramig 2.5mg tablets : 1 Naratriptan 2.5mg tablets : 18

Prescribing where St Mary'S Surgery is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Famotidine	0	H2-Receptor antagonists	1	0.00	0.78	0.23	-3.34

Allopurinol	74	Gout and cytotoxic induced hyperiuicaemia	99	0.75	0.89	0.05	-2.75
Allopurinol 100mg tablets : 46 Allopurinol 300mg tablets : 28
Spironolactone	19	Potassium-sparing diuretics and aldosterone antagonists	54	0.35	0.72	0.14	-2.68
Spironolactone 25mg tablets : 14 Spironolactone 100mg tablets : 5
Losartan potassium	41	Angiotensin-II receptor antagonists	358	0.11	0.50	0.19	-2.07
Losartan 25mg tablets : 4 Losartan 50mg tablets : 21 Losartan 100mg tablets : 16
Finasteride	28	Male sex hormones and antagonists	48	0.58	0.82	0.12	-2.05
Finasteride 5mg tablets : 28