Population impact of regulatory activity restricting prescribing of COX‐2 inhibitors: ecological study
Authors: Wheeler Benedict W. , Metcalfe Chris , Gunnell David , Stephens Peter , Martin Richard M. 
Published: July 2009

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Cyclooxygenase‐2 (COX‐2) inhibitors are selective nonsteroidal anti‐inflammatory drugs (NSAIDs), purported to demonstrate lower gastrointestinal toxicity than nonselective NSAIDs.

• Prescriptions of selective COX‐2 inhibitors declined internationally after 2004 following voluntary withdrawal and regulatory intervention because of possible cardiovascular side‐effects.

• A study in Canada indicated that rates of gastrointestinal haemorrhage actually increased during the period of increasing COX‐2 inhibitor prescriptions, due to the increased number of people receiving NSAIDs.

WHAT THIS STUDY ADDS

• The reduction in availability of COX‐2 inhibitors in the UK was temporally associated with a favourable reversal of the trend in emergency hospital admissions for acute myocardial infarction among people aged ≥65 years, but there were no related changes in myocardial infarction mortality trends.

• There was some indication that hospital admissions for gastrointestinal haemorrhage among people aged 55–64 years started to increase following a previously declining trend, but this change predated withdrawal/regulation of COX‐2 inhibitors by up to 2 years.

• The withdrawal/regulation of coxibs did not appear to have any adverse impact on population health and may have been beneficial.

AIMS

To investigate impacts of withdrawal and regulatory advice regarding cyclooxygenase‐2 (COX‐2) inhibitors on UK population rates of gastrointestinal haemorrhage and acute myocardial infarction (MI).

METHODS

Ecological time series study of prescribing, mortality and hospital admission trends in people aged ≥55 years.

RESULTS

Withdrawal and regulatory advice limiting COX‐2 inhibitor availability from 2004 were temporally associated with reversal of previously unfavourable trends in emergency MI admissions among people aged ≥65 years. Annual admission rate trends changed from +4.6% to −3.1% (P < 0.001) among women and from +2.1% to −3.8% (P= 0.003) among men. Absolute changes in average annual trend in the number of individuals aged ≥65 years admitted following MI were from +981 (1999–2004) to −819 (2004–2006) per year for women and from +713 to −995 for men. No change in trend was apparent among people aged 55–64 years, or in MI mortality trends. There was some suggestion of an unfavourable change in admission trends for gastrointestinal haemorrhage among 55−64‐year‐olds, although this appeared to occur prior to COX‐2 inhibitor withdrawal/regulation by up to 2 years. These trends were not apparent in older people, or in gastrointestinal haemorrhage mortality rates.

CONCLUSIONS

Withdrawal/regulation of COX‐2 inhibitors was temporally associated with a favourable reversal of population‐level hospital admission trends in MI among people aged ≥65 years. Unfavourable reversal of previous declines in gastrointestinal haemorrhage admissions probably occurred before changes in COX‐2 inhibitor availability. Withdrawal/ regulation of COX‐2 inhibitors did not appear to have any adverse impact on population health and may have been beneficial.