Static outliers for Hamstreet 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 Hamstreet Surgery is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Sulindac☰	4	Non-steroidal anti-inflammatory drugs	567	0.01	0.00	0.00	7.80
Sulindac 200mg tablets : 4
Ferrous gluconate☰	184	Oral iron	456	0.40	0.03	0.05	6.85
Ferrous gluconate 300mg tablets : 184
Prochlorperazine mesilate☰	10	Drugs used in nausea and vertigo	373	0.03	0.00	0.00	6.19
Stemetil 12.5mg/1ml solution for injection ampoules : 1 Prochlorperazine 12.5mg/1ml solution for injection ampoules : 9
Calcium acetate/magnesium carbonate☰	1	Phosphate binding agents	1	1.00	0.05	0.18	5.24
Osvaren 435mg/235mg tablets : 1
Dornase alfa☰	5	Mucolytics	87	0.06	0.00	0.01	5.15
Pulmozyme 2.5mg nebuliser liquid 2.5ml ampoules : 5

Prescribing where Hamstreet Surgery is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Furosemide☰	398	Loop diuretics	655	0.61	0.86	0.09	-2.78
Furosemide 20mg tablets : 187 Furosemide 40mg tablets : 211
Nitrofurantoin☰	160	Urinary-tract infections	195	0.82	0.97	0.06	-2.39
Nitrofurantoin 100mg modified-release capsules : 132 Nitrofurantoin 100mg tablets : 7 Nitrofurantoin 100mg capsules : 6 Nitrofurantoin 50mg tablets : 15
Amoxicillin☰	194	Broad-spectrum penicillins	309	0.63	0.81	0.09	-2.13
Amoxicillin 500mg capsules : 131 Amoxicillin 250mg/5ml oral suspension : 48 Amoxicillin 125mg/5ml oral suspension : 9 Amoxicillin 250mg capsules : 6
Losartan potassium☰	278	Angiotensin-II receptor antagonists	2410	0.12	0.50	0.19	-2.06
Losartan 25mg tablets : 78 Losartan 50mg tablets : 92 Losartan 100mg tablets : 98 Losartan 12.5mg tablets : 10
Ferrous fumarate☰	51	Oral iron	456	0.11	0.57	0.24	-1.96
Ferrous fumarate 210mg tablets : 49 Ferrous fumarate 140mg/5ml oral solution sugar free : 2