Static outliers for Waca 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 Waca PCN is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Daptomycin	7	Some other antibacterials	63	0.11	0.00	0.00	101.00
Daptomycin 500mg powder for solution for infusion vials : 7
Sulfur	5	Topical preparations for acne	839	0.01	0.00	0.00	15.08
Salicylic acid 2% / Sulfur 2% in Aqueous cream : 5
Chlorhexidine acetate	1	Chlorhexidine salts	70	0.01	0.00	0.00	14.79
Chlorhexidine acet 0.015%/Cetrimide 0.15% irrig soln 1L btl : 1
Mercaptamine hydrochloride	5	Tear deficiency, eye lubricant/astringent	1919	0.00	0.00	0.00	8.78
Mercaptamine 0.5% eye drops : 5
Isotretinoin	207	Oral preparations for acne	222	0.93	0.04	0.13	6.88
Isotretinoin 20mg capsules : 188 Isotretinoin 10mg capsules : 18 Roaccutane 20mg capsules : 1

Prescribing where Waca PCN is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score
Chlorhexidine gluconate	69	Chlorhexidine salts	70	0.99	1.00	0.00	-14.79
Chlorhexidine gluconate 1% cream : 1 Chlorhexidine gluconate 4% solution : 18 Chlorhexidine glucon 0.015%/Cetrimide 0.15% soln 100ml sach : 1 HiBiScrub 4% solution : 44 Cepton 1% medicated skin wash : 1 Hydrex 4% Surgical Scrub : 3 ChloraPrep solution 3ml applicators : 1
Co-cyprindiol (Cyprote acetate/ethinylestradiol)	15	Oral preparations for acne	222	0.07	0.96	0.13	-6.88
Co-cyprindiol 2000microgram/35microgram tablets : 9 Dianette tablets (Bayer) : 6
Gliclazide	1719	Sulfonylureas	4117	0.42	0.93	0.11	-4.55
Gliclazide 80mg tablets : 1198 Gliclazide 30mg modified-release tablets : 182 Gliclazide 40mg tablets : 279 Gliclazide 60mg modified-release tablets : 56 Gliclazide 40mg/5ml oral suspension : 3 Edicil MR 30mg tablets : 1
Alendronic acid	1984	Bisphosphonates and other drugs	3589	0.55	0.87	0.07	-4.28
Alendronic acid 10mg tablets : 3 Alendronic acid 70mg tablets : 1936 Alendronic acid 70mg/100ml soln unit dose sugar free : 10 Alendronic acid 70mg effervescent tablets sugar free : 21 Binosto 70mg effervescent tablets : 14
Cetomacrogol	0	Vehicles	2	0.00	0.93	0.25	-3.76