Validation of The Health Improvement Network (THIN) primary care database for monitoring prescriptions for smoking cessation medications.

PURPOSE: Evaluation of tobacco policy requires high quality and timely data on smoking cessation behaviour in the general population and in relevant target groups. Electronic primary care databases have the potential to provide a valuable source of data due to their size and continuity, and the availability of demographic and socioeconomic data. We therefore sought to investigate whether The Health Improvement Network (THIN) prescribing data are complete and can therefore be used to monitor trends in the prescribing of smoking cessation medications.
METHODS: The THIN smoking cessation medication prescriptions data for England were compared with smoking cessation medication dispensing data from NHS Prescription Services for January 2004 to December 2005.
RESULTS: Throughout the period the rates of prescribing and dispensing were very similar, both for nicotine replacement therapy (NRT) and bupropion combined, and for each type of medication alone. For NRT, dispensing exceeded recorded GP prescribing by 5.5% during the study period. For bupropion, prescribing exceeded dispensing by 5%.
CONCLUSIONS: THIN prescribing and national dispensing data are highly comparable. THIN prescribing data could potentially be used to monitor longitudinal trends in prescribing for smoking cessation medications.