Non-steroidal anti-inflammatory drugs

March 2008


Introduction

Data presented in these web pages relate to the prescribing of drugs used to treat rheumatic diseases and gout in Scotland for the financial years 1993/94 to 2006/07, inclusive.  Statistics given include the volume, as defined by number of prescribed items or defined daily dose, and the gross ingredient cost of the drugs at both Scotland and NHS Board level.  The report concentrates on the main drugs within BNF section 10.1, that is, the non-steroidal anti-inflammatory drugs that form BNF sub-section 10.1.1.

It should be noted that drugs indicated for rheumatic diseases and gout can be used to treat other indications such as joint damage caused by a sports injury or headache therefore no guarantee can be given that the statistics presented relate solely to their prime function.

Arthritis is an inflammation of the joints.  It affects an estimated 9 million people in the UK, including around 12,000 children.  NHS Quality Improvement Scotland (NHS QIS) estimate that between 152,000 and 217,000 people in Scotland have rheumatoid arthritis or osteoarthritis based on prevalence rates of 0.5 - 0.9% and 2.5 - 3.3% respectively, as reported by the Scottish Medicines Consortium .  No cure exists at present but treatment is available to alleviate the pain and some of the misery caused by joint stiffness.  

There are about two hundred different kinds of arthritis.  The common types are:

• osteoarthritis - where the cartilage protecting the bones is worn away.  About 5 million people in the UK have osteoarthritis, mainly elderly but it can also affect younger people through sport injuries.
  
• rheumatoid arthritis - is a more severe but less common condition.  The body's immune system attacks and destroys the joint lining, making the joints painful, unstable and deformed.  This type of arthritis tends to affect younger people and is more common in women than in men.  It affects about one in 100 people.    
  
• ankylosing spondylitis - is the third most common type of arthritis in the UK.  Inflammation occurs in the spine and pelvis causing the joints to stiffen and sometimes 'lock'.  This disease affects more men than women 
  
• gout - caused by uric acid crystals forming in the joints, particularly the big toe, ankles, hands and wrists.  It can be very painful, but is easily controlled by medication and a change in diet.

Information of the various forms of arthritis, its treatment and prevalence can be found on the following Internet sites:

• BBC Health   
• Arthritis Research Campaign
• Arthritis Care
• NHS Direct 
• Back Care

Rheumatic diseases and gout

Medicines used in the treatment of rheumatic diseases and gout are given in the British National Formulary (BNF)  section 10.1.  This section is divided into sub-sections and paragraphs:

• BNF 10.1.1 - NSAIDs.   A non-steroidal anti-inflammatory drug(NSAID) is indicated for pain and stiffness resulting from inflammatory rheumatic disease. The drugs have analgesic, antipyretic and anti-inflammatory effects and are non-narcotic, however, they can have an adverse effect on the gastro-intestinal and renal systems.
• BNF 10.1.2 - Corticosteroids.  Treatment with corticosteroids is reserved for specific indications, e.g., where other anti-inflammatory drugs are unsuccessful.
• BNF 10.1.3 - Drugs which suppress the rheumatic disease process.   These drugs, unlike NSAIDs, can affect the progression of disease but may require two-six months of treatment for a full therapeutic response.
• BNF 10.1.4 -  Gout and cytotoxic induced hyperuricaemia.  Acute attacks of gout are normally treated with high doses of an NSAID, but the long term control may require the use of other drugs

Summary

The prescribing of drugs indicated for rheumatic diseases and gout (BNF 10.1) in Scotland between 1993/94 and 2006/07 has been reviewed.  A summary of the main findings is given below.

• A total of 2.47 million items were prescribed in Scotland during 2006/07, a decrease of some 84,870 (3.3%) from the previous year. A fall in the prescribing of NSAIDs (BNF 10.1.1) was the principal reason.
  
• Prescribing of NSAIDs, the main section within BNF 10.1, has fallen for the third consecutive year down by 1%, 12.4% and 5.1% respectively between 2004/05, 2005/06 and 2006/07.
  
• Main reasons for the fall are the withdrawal of two COX II drugs, prescribing restrictions on others in the group and a fall in the prescribing of some other NSAID drugs.
  
• The gross ingredient cost of drugs within BNF 10.1 has risen slightly from £21.78 million in 2005/06 to £21.85 million in 2006/07, the first rise in cost observed since 2003/04. 
  
• During the past three financial years the NSAID drug cost fell from £34.4 million in 2003/04 to £31.9 million in 2004/05, to £19.3 million in 2005/06 and £19.1 million in 2006/07.  Generic price control on the principal NSAID drugs has played a large part in reducing the gross ingredient cost.
  
• It is estimated that in 2006/07, some 210,000 people (4.9%) in Scotland aged 15 and over, are in daily receipt of a NSAID drug.
  
• At individual NHS board level, during 2006/07, Lanarkshire is the highest user with 6.5% of the population making daily use of a NSAID, while Lothian is the lowest at 3.3%.  

Data Source

Practitioner Services, a division of NHS Services Scotland process all NHS prescriptions for payment of pharmacies, dispensing doctors, and appliance suppliers.  This gives a full record from which trends in prescribing can be investigated at a detailed level.  The data includes prescribing by GPs, nurses, dentists, pharmacists and hospitals, where the latter was dispensed in the community.  Hospital dispensed prescriptions are NOT included in the figures.  The Information Services Division (ISD) cannot say what proportion of the drug dispensed is actually consumed.

A downloadable Excel file is provided that gives both the data behind the graphs and details of WHO DDD values. 

Figure 1 shows the number of prescribed items in total and by BNF sub-section for drugs indicated for rheumatic diseases and gout prescribed in Scotland from 1993/94 to 2006/07.

Figure 1 Number of prescribed items - Scotland 1993/94 to 2006/07


Source: Information Services Division, Healthcare Information Group.

BNF 10.1.2, Local corticosteroid injections, show little change over the fourteen years of the review period, remaining at around 11,000 prescribed items per annum. 

Non-steroidal anti-inflammatory drugs  account for over 80% of the items in BNF section 10.1.  Prescribing of these drugs shows a slow but steady increase of around 1% per annum from 1993/94 to 2000/01,  increasing to some 3% per annum up to 2003/04.  Thereafter NSAID prescribing begins to decline, the number of prescriptions issued in 2006/07 being lower than that for 1993/94  - 2.0 versus 2.1 million items. 

It has been postulated that the decrease in the prescribing of NSAIDs is due to a combination of the withdrawal/restriction of COX IIs and changes in the prescribing of some of the 'standard' NSAIDs.  The 'shortfall' being covered by increased prescribing of non-opiod analgesics, for example, paracetamol.  

Cyclo-oxygenase-2 inhibitors (COX II) were first introduced in June 1999 having a lower risk of gastro-intestinal side effects than the non-selective NSAIDs. However, concerns about cardiovascular safety led to the withdrawal of two of the drugs with the recommendation that the others be used only in those patients with a high risk of gastroduodenal ulcer perforation or bleeding.    The drugs involved are given in table 1

Table 1 - COX II (Cyclo-oxygenase-2 inhibitors

Source: Information Services Division, Healthcare Information Group

Figure 2 shows the number of prescribed items over time for COX II inhibitors.  Changes in the prescribing of COX IIs accounts for about half of the 2006/07 drop shown in Figure 1, and it is possible that minor analgesic prodcuts such as asprin (not in BNF Chapter 10) might have been used a substitute.

Figure 2 - Prescribing of COX II inhibitors 1999/00 to 2006/07

Source: Information Services Division, Healthcare Information Group

Seven drugs account for 96% of all non-selective NSAIDs, the prescribing of which are shown in figure 3, below.

Figure 3 - Top seven non-selective NSAIDS 1993/94 to 2006/07


Source: Information Services Division, Healthcare Information Group

In 2006/07 figure 3 shows that celecoxib is back in the top 7, replacing mefenamic acid. Both of these items have reduced prescribng in 2006/7 compared to 2005/6, with mefenamic acid reducing more than celecoxib. Historically prescribing of the 'older' NSAIDS (for example, diclofenac, naproxen, ibruprofen, meloxicam) declined following the introduction of the COX II's in 1999. However in 2003, reports of problems with the 'newer' drugs (COX II's) became available and this saw a slow reserving trend in the number of the 'older' NSAID being prescribed, although this was not evident until 2005. Between 2005/06 and 2006/07, the prescribing of the COX IIs fell by 18,899 items whereas the prescribing of the 'older' NSAIDs decreased by 89,508.

ISD cannot say from this data how many people are receiving these drugs.  However, an approximation can be found from using the defined daily dose (DDD) as developed by the World Health Organisation (WHO).  The DDD is defined as the assumed average maintenance dose per day for a drug used in its main indication in adults.  DDDs are derived from the international use of the substance in question.  As British prescribing patterns may differ from the accepted international value, each DDD should be regarded as a technical value, a close approximation of an average of the actually used doses.  The DDDs are therefore not necessarily the most frequently prescribed or used doses.

This approach has the advantage of eliminating problems associated with prescribed items (variation in the amount prescribed, differing formulations) and gross ingredient cost (price variation over time and price difference between products).

WHO defined daily dose (DDD) values for the drugs within BNF 10.1 are given in a downloadable Excel file.

Figure 4 shows the defined daily dose given as the number of DDDs per 1,000 population per day.  This value offers an explanation of what proportion of the population may receive a certain drug treatment.  For example an estimated drug consumption of 10 DDDs per 1000 population per day corresponds to a daily use of the drug by 1% of the population.  The population used is the mid-year estimate produced by the General Registrar Office for Scotland, but restricted to persons aged 15 and over.

Figure 4 - Number of DDDs per 1000 population (aged 15+) per day 1993/94 to 2006/07


Source: Information Services Division, Healthcare Information Group.

The prescribing pattern in figure 4 is essentially the same as that shown in figure 1, the number of prescribed items, again indicating that lengths of treatments per prescription have not materially changed over time.  Daily use of drugs indicated for rheumatic diseases and gout, as calculated from the defined daily dose, are shown in table 2.

Table 2 Estimated population using drugs for rheumatic diseases and gout

Source: Information Services Division, Healthcare Information Group

The figures in table 2 are estimates only, the actual patient base is currently unknown.

The gross ingredient cost, that is the cost of the drug before the deduction of any supplier discount and patient charges, is given in figure 5.

Figure 5 - Gross Ingredient Cost (£) of drugs in BNF 10.1 - 1993/94 to 2006/07


Source: Information Services Division, Healthcare Information Group.

The total gross ingredient cost of "rheumatic/gout drugs" during 2006/07 was £21.8 million, down £14.61 million from the 2003/04 peak.  The drop is due to a decline in prescribing of the NSAIDs, withdrawal and prescribing restriction on the COX II NSAIDs and the effects of price control on drugs in the NSAID group.  

Other drugs within BNF 10.1, that is, the corticosteroids (BNF 10.1.2), drugs which suppress the rheumatic process (BNF 10.1.3), and drugs indicated for gout and cytotoxic-induced hyperuricaemia contributed  £0.18, £1.71 and £0.89 million respectively to the 2006/07 total ingredient cost. 

Prescribing Statistics - NHS Boards

a) Usage

The following charts, for reasons of clarity, use the NHS Board cipher rather than the board name.  Table 3 maps the cipher to the board name.

Table 3 - NHS Board Cipher -Translation

The number of DDDs per 1,000 population per day is used to permit comparison between the NHS boards, as shown in figure 6.

Figure 6 - NSAIDs - DDDs per 1000 population (aged 15+) per day - NHS Board 1993/94 & 2006/07


Source: Information Services Division, Healthcare Information Group.
Footnote: Data for NHS Greater Glasgow and Clyde and NHS Highland in 1998 represents the 'old'
health board structure of Greater Glasgow Health Board and Highland Health Board.  Data for 2006/07
represents the new formation of these boards, to incorporate the parts of Argyll and Clyde from April 2006

The percentage of the population in 2006/07 'using' NSAIDs daily varies from 3.3% in Lothian to 6.5% in Lanarkshire which equates to around 21,800 and 29,000 people respectively.  It must be emphasised that these figures are purely estimates, the actual patient bases is unknown,  Nine NHS boards are above the Scottish average (4.9%), viz:

• 6.5% - Lanarkshire
• 6.2% - Ayrshire and Arran
• 6.0% - Western Isles
• 5.4% - Orkney
• 5.3% - Greater Glasgow and Clyde
• 5.2% - Fife
• 5.2% - Dumfries and Galloway
• 5.1% - Forth Valley
• 4.9% - Highland

b) Costs

Figure 7 shows that gross ingredient cost (£) for NSAIDs per head of population has fallen from a peak of £8.21 in 2003/04 to £4.48 in 2006/07.  The 2006/07 cost is actually lower than that recorded in 1993/94, that is, £5.20.

Figure 7 - Gross Ingredient Cost (£) per head of population (aged 15+)  -  by NHS Board 1993/94 & 2006/07

Source: Information Services Division, Healthcare Information Group.
Footnote: Data for NHS Greater Glasgow and Clyde and NHS Highland in 1998 represents the 'old'
health board structure of Greater Glasgow Health Board and Highland Health Board.  Data for 2006/07
represents the new formation of these boards, to incorporate the parts of Argyll and Clyde from April 2006

The effect of price controls, withdrawal of two COX II NSAIDS & prescribing restrictions on the remaining COX IIs, and the reduction in prescribing of NSAIDs in general have all contributed to the lowering of drugs costs in the NSAID category  BNF 10.1.1. 

Main contact: Prescribing

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