Study selection and data
extraction
Two reviewers (JOC, NB) independently screened titles, abstracts and
read the full text of eligible studies to identify relevant studies for
inclusion. Disagreements were resolved by a third reviewer (SAP). Pairs
of reviewers extracted data from all included studies and disagreements
were resolved by discussion. We extracted the following study features:
- Study characteristics: first author and publication year, publishing
journal, study design, setting.
- Study period: observation period (beginning and end year of
observation).
- Data source (s): initial data source to ascertain opioid use,
classified as prescribing records or pharmacy dispensing data; the
extent of population coverage of the data source used (e.g., local,
regional or nationwide); and other sources of data used in the study
(e.g., medical records, surveys).
- Study population: the size of the study population, overall and per
groups compared; the age of included subjects, classified as adults
(18 years or older), elderly (65 years or older), all age groups (no
age restrictions) and other; inclusion and exclusion criteria for
study participation and health conditions evaluated.
- LTOT measures:
- Terminology related to LTOT definition, such as ‘Chronic’ or
‘Persistent’.
- LTOT definition, classified as A) duration measures (supply days or
days of use, length of the opioid use episode, prescription fills
within specified time periods) and B) additional measures (number of
prescriptions or fills, opioid dose, continuous use of opioids, or
other criteria). Opioid dose is generally measured by Defined Daily
Doses (DDD) or Oral Morphine Equivalents (OME)[16] and continuous use of opioids is commonly
measured by assessing consecutive days or months of opioid use or a
lack of a defined gap period between prescriptions.
- Rationale supporting LTOT definition and whether studies used more
than one LTOT definition.
- Rates of LTOT and the denominator used in the estimate (e.g., whole
population, healthcare enrollees, people using opioids, people with
specified health conditions).