Opioid prescribing for chronic musculoskeletal pain
To characterise opioid prescribing for patients with chronic musculoskeletal pain in primary care practices in London and the Midlands and estimate prescription costs.
Secondary data analysis was performed on prescription data from the COPERS (Coping with Persistent Pain, Effectiveness Research into Self-Management) trial, which examined the effectiveness and cost-effectiveness of group self-management in chronic musculoskeletal pain. Prescription data for 703 patients over a 12 month period were extracted from GP electronic records. For each opioid prescription, morphine equivalent doses were calculated using the potency equivalence with oral morphine. The average daily morphine equivalent doses for each participant were calculated over the 12 month period.
60% (421/703) of patients with chronic musculoskeletal pain were prescribed opioids. Among those prescribed an opioid, the number of opioid prescriptions varied from 1 to 52 per year, with 71% (298/421) receiving 3 and more prescriptions a year. A total of 3,319 opioid prescriptions were issued over the study period, of which 53% were for strong opioids (buprenorphine, fentanyl, morphine, oxycodone, tapentadol and tramadol). The mean number of opioid prescriptions per patient prescribed any opioid was 8 (SD=7.9). The average morphine equivalent dose was 10.6mg/day (SD=32.3). A third of patients on opioids were prescribed more than one type of opioid; the most frequent combinations were codeine plus tramadol and codeine plusmorphine. Approximately 1.2% of patients (5/421) were prescribed an average morphine equivalent dose of 100 mg/day and higher. This was associated with a rise in average prescription numbers from 5.13 (SD=4.95) to 29.80 (SD=10.07), and an increase in cost from £59 (SD=139) to £2,031 (SD=1,637) per patient per year compared to those prescribed <20 mg/day. Prescription patterns were similar in London and the Midlands.
This study shows that long-term prescription of opioids for chronic musculoskeletal pain is common in primary care. The majority of patients in our study received low morphine equivalent doses (<20 mg/day), while 1.2% were prescribed doses of 120-180mg/day requiring referral to specialist care (The British Pain Society, 2010). Despite the low level of opioid over-prescription in primary care, the high economic cost of over-prescribing and the heavy burden of chronic pain nationally, stress the need for alternative pain management strategies to be further explored.