A geospatial analysis of naloxone distribution patterns in the Massachusetts overdose education and naloxone distribution program (MA OEND).

Introduction: This study describes the distribution and administration of naloxone throughout one state heavily impacted by the opioid overdose crisis. We sought to: 1) assess whether naloxone kits were used in rescue attempts in the same communities where they were distributed, and 2) explore how best to define geographical boundaries for comparing naloxone supply to demand, accounting for naloxone mobility patterns to identify areas of surplus or shortage.

Methods: used data from Massachusetts' Overdose Education and Naloxone Distribution (OEND) programs for 2018-2020, linking participants' residence, overdose rescue attempt, and refill locations at the ZIP code level. We built a Sankey plot describing the distribution and administration of naloxone between OEND program regions based on refill encounters with a reported rescue attempt. We algorithmically derived "naloxone service areas (NSAs)," defined as collections of municipalities that receive naloxone from high-volume naloxone distribution hubs. For each NSA, we calculated a coverage ratio (naloxone kits dispensed per opioid-related overdose death).

Results: From 2018-2020, the MA OEND programs had 88,085 naloxone dispensing encounters among 49,344 people. People reported a prior rescue attempt in 16 % of all observed encounters. There was substantial migration between residence and rescue attempt locations, with much naloxone distributed in Boston. The average naloxone dispensing-to-overdose death ratio was 14 kits per death over the three years, ranging from 8 to 32 kits per death across NSAs.

Conclusions: Naloxone kits are often used by people residing in communities other than where kits were distributed, with significant variation in coverage ratios across regions.