Static outliers for Sidcup Medical Centre

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 Sidcup Medical Centre is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Diethylamine salicylate	220	Rubefacients, topical NSAIDS, capsaicin and poultice	624	0.35	0.03	0.06	5.28
Algesal cream : 214 Diethylamine salicylate 10% cream : 6
Sodium oxybate	8	Hypnotics	1490	0.01	0.00	0.00	4.69
Sodium oxybate 500mg/ml oral solution sugar free : 8
Magnesium citrate	6	Magnesium	6	1.00	0.07	0.21	4.47
Magnesium citrate 100mg capsules : 3 Magnesium citrate 200mg tablets : 3
Influenza	287	Vaccines and antisera	295	0.97	0.08	0.22	4.05
Influvac sub-unit Tetra vacc inj 0.5ml pre-filled syringes : 276 Adjuvanted trivalent flu vacc (SA, inact) inj 0.5ml pfs : 11
Low protein cereals	5	Foods for special diets	162	0.03	0.00	0.01	3.95
Loprofin low protein breakfast cereal flakes (2 flavours) : 5

Prescribing where Sidcup Medical Centre is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Urea hydrogen peroxide	0	Removal of ear wax and other substances	1	0.00	0.83	0.34	-2.47

Permethrin	1	Parasiticidal preparations	4	0.25	0.84	0.25	-2.34
Permethrin 5% cream : 1
Amitriptyline hydrochloride	1373	Tricyclic and related antidepressant drugs	2034	0.68	0.84	0.08	-2.16
Amitriptyline 10mg tablets : 860 Amitriptyline 25mg tablets : 318 Amitriptyline 50mg tablets : 195
Procyclidine hydrochloride	153	Antimuscarinic drugs used in parkinsonism	327	0.47	0.84	0.21	-1.80
Procyclidine 5mg tablets : 153
Ganciclovir	0	Antivirals	1	0.00	0.68	0.42	-1.60