SELECTIVE COX 2 INHIBITORS AND NSAID PRESCRIBING PATTERNS IN IRELAND M. Teeling, K. Bennett, J. Feel

1
SELECTIVE COX 2 INHIBITORS AND NSAID
PRESCRIBING PATTERNS IN IRELANDM. Teeling, K.
Bennett, J. Feely,Dept of Pharmacology and
Therapeutics, Trinity College, St Jamess
Hospital, Dublin 8, Ireland.
2
Introduction

• Non steroidal anti inflammatory drugs (NSAIDs)
  are among the most commonly used medicines in the
  world
• Use is associated with gastrointestinal (GI)
  toxicity
• Selective COX-2 inhibitors are thought to reduce
  GI toxicity

3
Aim of this Study

• To investigate what effect, if any,
• the availability of selective COX-2 inhibitors
  has had on NSAID prescribing patterns in Ireland

4
Methods (1)

• The General Medical Services(GMS) scheme provides
  free health service to 31 of the Irish
  population(1.2M)
• Eligibility is means tested
• The GMS provide details on prescription claims
  and also demographic data on patients such as age
  and sex
• Total annual cost of prescription items was 434
  million in 2001.

5
Methods (2)

• GMS database was reviewed from Dec 1999-Nov 2001
• First 6 months lead-in phase
• (NSAID and anti-PU drug users excluded)
• Next 12 months study period
• ( patients gt 3 prescriptions of the same NSAID
  identified)
• Final 6 months follow-up period
• Information on age,sex and on co-prescribing
  of other medications, in particular anti-PU
  drugs, collected from study and follow-up periods

6
Methods (3)

• The WHO ATC (Anatomical Therapeutic Chemical)
  classification was used to identify drugs in the
  database as follows
• M01A (Anti-inflammatory and anti-rheumatic
  products, non-steroids)
• A02B (Drugs for treatment of peptic ulcers)
• NSAIDs were classified as selective or
  non-selective
• Odds ratios were calculated, using logistic
  regression (SAS package)

7
(No Transcript)
8
Results
9
Table 1 Prescription of NSAIDs effect of age
10
Table 2 Prescription of NSAIDs - number of
other prescriptions
11
Table 3 ORs for co-prescribing of anti PU drugs
on or after the first month of NSAIDs versus no
NSAIDs

• NSAID OR (95C1)
• No NSAIDs 1.00
• Celecoxib 2.04 (1.67,2.49)
• Rofecoxib 2.11 (1.83,2.24)
• Nimesulide 2.09 (1.95,2.24)
• Diclofenac 1.36 (1.30,1.43)
• Mefanamic Acid 1.31 (1.22,1.40)
• Naproxen 1.53 (1.34,1.74)
• Figures adjusted for age, gender and
  polypharmacy

12
Discussion (1)

• The selective COX-2 inhibitors (celecoxib and
  rofecoxib) together with nimesulide accounted for
  approximately 25 of the GMS prescriptions for
  NSAIDs and almost 50 (7.3 million) of the total
  cost for anti-inflammatory and anti-rheumatic
  products in 2001
• Expenditure on anti-PU drugs accounted for over
  8 of total drug costs under the GMS in 2001
  (36.9 million)

13
Discussion (2)

• Cost of COX-2 inhibitors greatly exceed those of
  conventional non-selective NSAIDs as follows
  (DDD/month)
• Indomethacin 3.50
• Ibuprofen 7.00
• Diclofenac 11.00
• Mefanamic acid 8.00
• Naproxen 9.00
• Nimesulide 21.00
• Rofecoxib 34.50
• Celecoxib 32.00
• defined daily dose (WHO)

14
Discussion (3)

• Limitations of the study
• Database records number of prescriptions
  dispensed.
• Database does not have access to diagnoses.
• BUT
• Records were included only if gt 3 prescriptions
  dispensed during the study period and
• Adjustments for age, gender and polypharmacy were
  made

15
Conclusions (1)

• In this study, Cox-2 selective inhibitors were
  prescribed more frequently in older age groups
  and in those with a higher rate of polypharmacy
  (as noted from the GMS database in Ireland)
• These findings suggest that COX-2 inhibitors are
  preferentially prescribed to the more vulnerable
  patients.

16
Conclusions (2)

• However, even when the figures were adjusted for
  age, gender and polypharmacy, anti-PU drugs were
  still co-prescribed more frequently in the Cox-2
  selective inhibitor group
• This suggests that there may be other unaccounted
  for risk factors or
• that prescribers are still uncertain of the
  safety of COX-2 selective inhibitors in
  vulnerable patient groups

17
Conclusions (3)

• Since selective COX-2 inhibitors are more
  expensive than many of the conventional
  non-selective NSAIDs, these results suggest that
  COX-2 inhibitors may not be cost-effective.