Investigating the prescribing trajectory and geographical drug utilisation patterns of gabapentinoids in primary care in England: an ecological study.

AIM This study aimed to investigate the prescribing trajectory, geographical variation and population factors including the socioeconomic status (SES) related to prescribing gabapentinoids in primary care in England. METHODS This ecological study applied practice-level dispensing data and statistics from the UK National Health Service Digital and Office for National Statistics from 2013-2019. The prescribing of gabapentinoids (in defined daily doses (DDDs)/1000 people) was measured annually and quarterly. General practices were categorised according to the quarterly prescribing in a group-based trajectory model. The one-year prescribing in 2018/19 was associated with practice-level covariates in a mixed-effects multilevel regression; adjusted for the cluster-effects of Clinical Commissioning Groups (CCGs) and mapped geographically. RESULTS The annual national prescription rate increased by 70% from 2800 to 4773 DDDs/1000 people in the time period 2013/14 to 2018/19. General practices were stratified into six trajectory groups. Practices with the highest level and the greatest increase in prescribing (n=789; 9.8%) are mainly located in the north of England and along the east and south coastline. Socioeconomic status, demographic characteristics and relevant disease conditions were significantly associated with the prescribing. For every decrease in the Index of Multiple Deprivation decile (becoming less affluent), prescribing of gabapentinoids significantly increased by 203 (95%CI: 183, 222) DDDs/1000 registrants. CONCLUSION Gabapentinoid prescribing trajectories varied across geographical regions and are associated with socioeconomic status, CCG locality (geography) and other population characteristics. These factors should be considered in future studies investigating the determinants of gabapentinoid prescribing and the risk of harms associated with gabapentinoids.