Opioid prescribing across Scotland - rates and variations

The problem

Opioids are well-established as effective agents for acute pain and cancer-related pain, with systematic reviews also confirming their effectiveness in some chronic non-malignant pain conditions. Opioids are associated with many side effects and longer term adverse effects but despite these concerns, prescription of opioids, misuse rates, overdose and opioid related deaths have all increased steadily, with most published data coming from the USA. Detailed UK data on opioid prescribing are currently lacking although there is limited evidence of overall increased prescribing. In Scotland, in the year to April 2012, there were 2,263,233 prescriptions for opioids dispensed (excl. compound preparations) at a gross ingredient cost of >£29.6M

The approach

We aimed to describe opioid prescription rates over a 10-year period across Scotland and explore the relationship between socio-demographic factors and local/regional opioid prescribing rates. Data were obtained from Information Services Division (ISD) of NHS Scotland, including the number of paid (prescription) items and number of defined daily doses of all opioids prescribed and dispensed between April 2003 and March 2012, by individual drug. For 2012 only, data included classification by: i) Health Board area; ii) GP practice; iii) socio- demographic factors (Scottish Index of Multiple Deprivation (SIMD) quintiles); v) individual exposure to drugs. Classification of drugs is based on the British National Formulary and subdivided into “weak”, “strong” and “combination” opioids.

Findings

Initial analysis finds a continuous and substantial increase in the rate of prescription of opioids over the 10-year period. The most commonly prescribed drug was co-codamol (over 2 million prescription items in 2012). Tramadol showed an almost threefold increase over the ten-year period; >1.01M items in 2012. A graduated rate of prescribing across the SIMD quintiles in 2012 was seen, with those in the most deprived SIMD receiving 3.5 times the number of prescriptions compared to those in the most affluent. In 2012, 949,108 patients were prescribed any opioid or combination drug, representing almost a fifth of the Scottish population. Co-codamol was the most commonly prescribed (n=615,520 patients) opioid, followed by Tramadol (n=205,514 patients) and with over forty thousand patients prescribed morphine. There were marked differences in regional prescribing rates by NHS health board. Further analysis by age & sex of patients receiving opioid prescriptions and GP practice prescribing patterns is ongoing.

Consequences

This study demonstrates an increase in opioid prescribing throughout Scotland with apparent regional and socio-demographic variations. The reasons for these substantial increases are unclear. This study will help inform current practice and education, identify factors associated with good opioid prescribing and with actual or potential problems nationally.