Static outliers for Imperial College Health 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 Imperial College Health Centre is higher than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Dexamethasone☰	26	Use of corticosteroids	57	0.46	0.03	0.03	16.39
Dexamethasone 2mg tablets : 2 Dexamethasone 500microgram tablets : 24
Paliperidone☰	2	Antipsychotic drugs	71	0.03	0.00	0.00	15.32
Paliperidone 3mg modified-release tablets : 2
Glipizide☰	6	Sulfonylureas	51	0.12	0.00	0.01	7.93
Glipizide 5mg tablets : 6
Azelastine hydrochloride☰	9	Drugs used in nasal allergy	88	0.10	0.01	0.01	7.82
Azelastine 140micrograms/dose nasal spray : 9
Valsartan☰	34	Angiotensin-II receptor antagonists	219	0.16	0.02	0.02	7.12
Valsartan 80mg capsules : 28 Valsartan 160mg capsules : 6

Prescribing where Imperial College Health Centre is lower than most

BNF Chemical	Chemical Items	BNF Subparagraph	Subparagraph Items	Ratio	Mean	std	Z_Score	Plots
Medroxyprogesterone acetate☰	0	Parenteral progestogen-only contraceptives	1	0.00	0.88	0.16	-5.42
Prednisolone☰	31	Use of corticosteroids	57	0.54	0.88	0.06	-5.33
Prednisolone 5mg gastro-resistant tablets : 2 Prednisolone 5mg soluble tablets : 2 Prednisolone 1mg tablets : 8 Prednisolone 5mg tablets : 19
Benzydamine hydrochloride☰	0	Drugs for oral ulceration and inflammation	2	0.00	0.83	0.18	-4.47
Furosemide☰	81	Loop diuretics	157	0.52	0.86	0.09	-3.80
Furosemide 40mg tablets : 54 Furosemide 20mg tablets : 27
Glucose☰	0	Treatment of hypoglycaemia	1	0.00	0.75	0.21	-3.62