Table 1. UK studies of opioid prescribing in primary care

Study	Study period	Location	Study population	Findings
NTA (2011)¹	1991–2009	England	All prescriptions	Five-fold increase in prescribing opioids.Regional variations in prescribing.
Ruscitto et al (2015)⁴⁶	1995–2010	Tayside	Primary care	Increase in opioid prescribing.Larger increase in “strong”^a opioid prescribing.Associated factors: polypharmacy, social deprivation.
Curtis et al (2019)²	1998–2018	England	Primary care	Increases in prescribing between 1998 and 2016.Increase in ME amount prescribed much greater.Prescriptions decreased after 2016.Associated factor: geographical variation.
Zin et al (2014)¹³	2000–2010	England	Primary care	“Huge” increase in “strong”^a opioid prescribing.Majority (88%) for non-cancer pain.
Cartagena Farias et al (2017)³⁵	2000–2015	England	Primary careNon-cancer pain	Increasing numbers of people prescribed opioids.Prescribing for longer periods.Associated factors: age, social deprivation, regional variation.
Bedson et al (2016)⁴⁸	2002–2013	England	Primary careMusculoskeletal pain	Long-term prescribing increased to 2009; slight decrease after 2011.Increased prescribing of long-acting opioids.
Green et al (2012)⁴⁹	2004-2007(?)^b	North Staffordshire	Primary careJoint painAged >50	Factors associated with increased rates of prescription.Factors associated with “strong”^a opioid use.
Foy et al (2016)³³	2005–2012	West Yorkshire	Primary careNon-cancer pain	Prescribing of weaker opioids doubled.Six-fold increase in “stronger”^a opioid prescribing.Patient and prescriber factors associated with stepping up to “stronger” opioids.
Davies et al (2019)¹¹	2005–2015	Wales	Primary careNon-cancer pain	Large increase in prescribing of “strong”^a opioids.Associated factors: age, social deprivation, anxiety or depression diagnosis.
Jani et al (2020)⁵⁰	2006–2017	England	Primary care	Increased prescribing of opioids: codeine, morphine, tramadol, oxycodone.Initiated high doses tend to be maintained.Associated factors: social deprivation, regional variation, polypharmacy.
Mordecai et al (2018)³⁴	2010–2014	England	Primary care	Increase in amount (in ME) prescribed.Associated factors: social deprivation; regional variation.
Ponton & Sawyer (2018)³⁶	2012(?)^b	South East England	Primary carePatients prescribed high doses	Identified patients prescribed doses ≥120 mg ME of “strong”^a opioids as candidates for specialist input.
Ashaye et al (2018)⁵¹	2011–2012	London and Midlands	Primary careMusculoskeletal pain	Long-term prescribing common.Possible overprescribing in more than a quarter of patients receiving “strong”^a opioids.
Public Health England (2019)³²	2015–2018	England	Primary care	Prescriptions and proportion of population prescribed opioids declining from historically high rates.High rates of long-term prescribing.Associated factor: social deprivation, polypharmacy.
Bastable & Rann (2019)³⁷	2018	East England	Primary carePatients prescribed high doses	Identified patients prescribed opioid doses ≥120 mg ME.Co-prescribing of Z-drugs, benzodiazepines, and gabapentinoids.

ME = Morphine equivalent..
^a Drugs categorised as “strong” vary between studies, but always include morphine, oxycodone, and fentanyl.
^b This is estimated from the published text, which does not indicate the data collection period.