Over the past few weeks I have been looking at GP Prescribing data from the Health & Social Care Information Centre, which presents the number of items and cost of all the different medication prescribed and dispensed by GP practices across the UK. The dataset amounts to millions of rows of data each month. I am trying to find trends and patterns that occur with regards to the number of items that occur within this data.

As part of my internship, provided by the Q-step programme,  I am trying to think more quantitatively.

One of the things I have learnt is that when given a dataset the first thing to do with it is to break it down and make sure the meaning of everything is understood. Therefore with the data I am looking at I researched the meaning of each heading for the columns on the dataset. In this blog I will explain what each of these terms mean.

The British National Formulary (BNF)

Central to the GP prescribing data is the BNF. This is the British National Formulary which is produced by The British Medical Association and the Royal Pharmaceutical Society. It is used to give doctors and nurses advice on the selection, prescribing, dispensing and administration of medication in the UK. The BNF classifies medicines into therapeutic groups which are known as BNF Chapters. There are 15 BNF chapters and some ‘pseudo BNF chapters’ (numbered 18 to 23) that include items such as dressings and appliances. The 15 BNF Chapters are:

• Chapter 1:Gastro-intestinal System
• Chapter 2: Cardiovascular System
• Chapter 3: Respiratory System
• Chapter 4: Central Nervous system
• Chapter 5: Infection
• Chapter 6: Endocrine System
• Chapter 7: Obstetrics, Gynaecology and Urinary- tract disorders
• Chapter 8: Malignant Diseases and Immunosuppression
• Chapter 9: Nutrition and blood
• Chapter 10: Musculoskeletal and joint diseases
• Chapter 11: Eye
• Chapter 12:Ear, nose, and oropharynx
• Chapter 13: Skin
• Chapter14: Immunological Products and Vaccines
• Chapter 15: Anesthesia

Under each BNF Chapter there are subsections for example, under Chapter 2 (Cardiovascular System) one of the subsections is 2.12 Lipid-regulating drugs.

The BNF Code is the unique code that each medication has. An example of a BNF Code is 0212000U0AAADAD which is for the drug Simvastatin Tablet 40mg. The BNF Code for each drug is formed as follows:

• Characters 1 & 2 show the BNF Chapter (02)
• 3 & 4 show the BNF Section (12)
• 5 & 6 show the BNF paragraph (00)
• 7 shows the BNF sub-paragraph (0)
• 8 & 9 show the Chemical Substance (U0)
• 10 & 11 show the Product (AA)
• 12 & 13 indicate the Strength and Formulation (AD)
• 14 & 15 show the equivalent (AD). The ‘equivalent’ is defined as follows:
  • If the presentation is a generic, the 14th and 15th character will be the same as the 12th and 13th character.
  • Where the product is a brand the 14 and 15 digit will match that of the generic equivalent, unless the brand does not have a generic equivalent in which case A0 will be used.

The BNF Name is the individual preparation name for each drug. It includes the name of the drug, which could be branded or generic, followed by form it comes in and the strength of the medication. On the GP Prescribing Data – Presentation Level  dataset I used, the BNF names were often presented in an abbreviated form due to the limited number of characters available in the dataset.

Other terms

• The Strategic Health Authorities (SHA) is an NHS organisation established to lead the strategic development of the local health service and manage Primary Care Trusts and NHS Trusts and are responsible for organising working relationships by getting service level agreement.
• A Primary Care Trust (PCT) are under SHAs and are local organisations that are responsible for managing health services in the community. Examples of PCT are GP surgeries, NHS walk-in centres, dentists and opticians. However in the last 2-3 years the PCTs have been converted to Care Commissioning Groups (CCG), but much of the data that I was looking at talks about PCTs.
• Items are defined as the number of items that were dispensed in the specified month. A prescription item is a single supply of a medicine, dressing or appliance written on a prescription form. If one prescription form includes four medicines, it is counted as four prescription items.
• Quantity is the drug dispensed measured in the units. The units are dependent on the makeup of the medication, for example if it is a tablet or capsule the quantity will be the number of tablets or capsules, whereas if it is a solid such as a cream or gel the quantity will be in grammes.
• Net Ingredient Cost (NIC) is the price of the drug written on the price list or drug tariff.
• Actual Cost is the estimated cost to the NHS. It is calculated by subtracting the average percentage discount per item (based on the previous month) from the Net Ingredient Cost, and adding in the cost of a container for each prescription item. It is usually lower than NIC.
• Period is the year and month that the dataset covers.

Now that I understand the meanings of each column of the dataset I am looking at, I am trying to find new things with it. Feel free to refer back to this blog when reading my future blogs on my findings, especially if you stumble upon something you have forgotten the meaning of.