TABLE 1.

Select input parameter values and processes within the Researching Effective Strategies to Prevent Opioid Death (RESPOND) model.^a

Model attributes and processes	Description	Sources
Cohort characteristics	Simulated population using opioids in Massachusetts
Population size	394 641 at the start of study period (beginning of 2020); increases by an average of 17 950 per year	MA DPH, NSDUH 2015–2018, Barocas et al.
Proportion male	62.7% male at beginning of study period	MA DPH, NSDUH
Age	Mean age: 47 at beginning of model initialization	MA DPH, US Census 2010
Active use	70.5% of total population actively using at beginning of study period	NSDUH 2015
Injection drug use	25% of active users and 9% of non-active users are assumed to have a history of injection drug use at model initialization	NSDUH 2013, Hudgins et al. [44], Adams et al. [45]
Transitions off treatment	Users can move from non-active to active as well as active to non-active use (bidirectional). These probabilities are estimated using published data	Neaigus et al. [46], Shah et al. [47], Nosyk et al. [48]
Background mortality	Based on all-cause mortality data from 2014, stratified by age group and sex. Remains the same for all treatment modalities	NVSS
Overdose	Weekly probability of overdose function of age, sex and route of administration; 13–14% of overdoses were fatal.	MA DPH
Treatment	The probability of overdose under no treatment was informed by surveillance data. All MOUD decreased the probability of overdose (0.4 hazard for buprenorphrine–naltrexone, 0.75 for methadone, and 0.86 for injectable naltrexone). Overdose not possible within detoxification or a correctional setting. Higher risk of overdose for those in post-treatment	MA DPH, Morgan et al. [25], Sordo et al. [26]
Route of administration	Only active users had a probability of overdose. Active injection drug use had a higher probability than active non-injection drug use (varied by age and sex). Empirically observed overdose fatalities from MA PHD were used a target for model calibration	MA DPH
Treatment	Simulated the provision of methadone, buprenorphine–naltrexone, and injectable naltrexone
Probability of initiating	Only active users not currently in treatment, detoxification or a correction setting could initiate treatment. Treatment engagement was informed by longitudinal person-level administrative data. At model initialization, 15.5% of total population is assumed to be on MOUD	MA DPH
Initiation effect	Upon initiating treatment, we assumed a percentage of active users immediately became non-active (i.e. remission). Methadone: 57%; community-based buprenorphine: 75%; injectable naltrexone: 90%; detoxification and correctional setting: 100%	CTN-0051
Transitions during treatment	While receiving treatment, users can move from active to non-active use (i.e. remission) or move from inactive to active use (i.e. relapse). These transition probabilities differed by treatment modality, gender and age and were estimated using a multi-state Markov model. Transitions did not occur within detoxification and correctional settings	CTN-051, CTN-027
Retention	While in treatment, there was a weekly probability of discontinuing treatment. This differed by treatment modality	Morgan et al. [4]
Post-treatment	Upon cessation of treatment, active users remain active and a set proportion of non-active users become active (i.e. relapse). These differed by treatment modality and overdose risk is increased compared to those in treatment or in no treatment. Individuals have a 25% weekly probability of returning to the ‘no treatment’ block	Bailey et al. [49], calibrated
Cost-effectiveness	Impact inventory and description of methods and sources included in the Supporting information
Quality adjusted life years (QALYs)	Health-related quality of life stratified by active versus non-active, injection versus non-injection, gender, age and treatment status	Wittenberg et al. [28], Murphy et al. [36]
Health-care utilization	Background and OUD costs (other than costs related to treatment), stratified by age, OUD state and treatment block	CTN
Treatment utilization	Pharmaceutical costs derived from the Federal Supply Schedule (FSS) in 2020 dollars. Treatment utilization based on expert opinion and published estimates from NIDA	FSS, NIDA, expert opinion
Costs of low-threshold SSP treatment	Pharmaceutical costs equivalent to standard of care buprenorphine, treatment costs identical but without a weekly nurse visit	Expert opinion (buprenorphine provider at a SSP)
Overdose	Cost of overdose estimated based on emergency department utilization data, costs of inpatient stays, and assumes the cost of ambulance for each overdose. Cost of a non-fatal overdose was $4557.35, cost of fatal overdose was $885.97.	Jiang et al., Murphy et al., MA DPH
Criminal justice involvement	Criminal justice costs, including the cost of policing, court, incarceration, and criminal victimization, stratified by OUD state and treatment block were estimated using CTN-0051 study data. Cost for those incarcerated ($1385 per week) was based on a reported estimate from Department of Corrections and was not stratified	CTN-0051, MA Department of Corrections

CTN, Clinical Trials Network; FSS, Federal Supply Schedule; MA DPH, Massachusetts Department of Public Health; MOUD, medications for OUD; NIDA, National Institute on Drug Abuse; NSDUH, National Survey on Drug Use and Health; NVSS, National Vital Statistic System; OUD, opioid use disorder; QALY, quality-adjusted life-year; SSP, syringe service programs.

^aInput values and sources available in the Supporting information.