(O) Variation in The Impact of a Policy to Restrict Coverage of Lidocaine 5% Plasters in Ireland

Publication Number: 639

Background: Lidocaine plasters are licensed for post-herpetic neuralgia in Ireland. Due to rising costs and use for other indications, restrictions on their coverage were introduced in 2017. From September 2017, new initiations required individual patient approval to be covered on Ireland’s state drug schemes, and from December 2017, current users required individual approval.

Objectives: To assess changes in the utilisation of lidocaine plasters following a restriction on their coverage, and regional variation following this.

Methods: This interrupted time series study of Ireland’s GMS state drug scheme used aggregate region-level data from the Primary Care Reimbursement Service (2015-2019). We determined the number of lidocaine plaster dispensings per 1,000 eligible population per month in each of 32 local health office regions. We also examined quantity and cost of dispensings. We modelled the level and trend change from September 2017 and from December 2017 using segmented regression via Stata's xtitsa package. To quantify variation between regions, we calculated the extremal quotient and winsored systematic component of variation (SCV) over time.

Results: Among 1,646,569 eligible individuals, lidocaine plaster dispensings peaked in August 2017 at 15.8 per 1,000 eligible individuals. There was an immediate level drop of -1.12 (95%CI -1.8, -0.44) dispensings/1,000 individuals in September 2017. The post-intervention trend was -2.84 (-3.18 to -2.51) dispensings/1,000 per month to December 2017, when there was a further level drop of -2.74 (-3.7, -1.79) dispensings/1,000. This reflected an overall reduction of 13.8 dispensings/1,000. There was a small positive trend post December 2017 (0.025 dispensing/1,000 per month, 95%CI 0.005, 0.045). Lidocaine dispensings varied 4.3-12.9 fold between the lowest and highest prescribing region during the study period, with the exception of one month (January 2018) when it varied 28.7 fold. Similarly the SCV ranged from 6.1-16.4, with the exception of January 2018 (55.7), and there was a trend of reduced variation over the study period. In August 2017, dispensing varied 4.7 fold between regions, an absolute difference of 24.6 dispensings/1,000. Compared to August 2017, rates dropped by 25.3%-51.0% across regions in September 2017, and by 92.0%-98.9% in December 2017. In February 2018, dispensings varied 5.7 fold (absolute difference 1.2 dispensings/1,000).

Conclusions: There were similar substantial reductions in lidocaine dispensings across regions, however there was greater variation following the first restriction phase, compared to the second. Although regional variation in use has decreased, in both relative and absolute terms, remaining variation may reflect differing population needs or equity of access.