Table 2. Summary of Included Studies on Mortality in the Elderly Patients Utilizing Methadone Maintenance Treatment.

MMT: Methadone Maintenance Treatment

Study	Study Period	Location	Design/Method	Population (Sample Size)	Age Range	Key Features	Major Findings on Aging	Major Findings on Opioids	Recommendations
Han et al. 2019 [23]	1996-2012	New York, USA	Secondary analysis of administrative data	Individuals in opioid treatment programs (N=50,000)	Above 60 years	Examined age trends, gender differences, primary substances used	The proportion of elderly (60+) increased, and more females in the older group	Heroin primary substance, small increases in alcohol and marijuana use	For more research on elderly opioid users, new care models needed
Grella and Lovinger, 2011 [16]	1978-2009	California, USA	Longitudinal follow-up of methadone patients	Original sample N=914, followed-up N=450	Above 60 years	Identified heroin use trajectories, gender differences in remission	Women are more likely to enter remission quickly	High rates of persistent drug use over 30 years	Treatment should address long-term drug use patterns and gender differences
Lofwall et al. 2005 [6]	Not given	Baltimore, USA	Cross-sectional survey	Older opioid maintenance patients (N=67)	Above 60 years	Examined physical and mental health characteristics, urine toxicology	Older patients had poorer physical health, more prescribed medications	The older group had fewer positive urine screenings for opiates	Develop more effective healthcare strategies for elderly opioid users
Rosen et al. 2011 [24]	1990-2009	United States	Literature review	Studies involving older heroin users and methadone patients (N=varied)	Above 60 years	Synthesized findings on aging heroin users	Highlighted the need for more research on older individuals in MMT	Findings inconsistent, need for larger sample sizes	Coordinated efforts needed for research and care for aging opioid users
Hser et al. 2017 [7]	1974-1997	California, USA	Longitudinal study	Original N=581, followed-up N=242	Above 60 years	Followed heroin addicts for over 30 years	Identified persistent drug use into the late 60s	Early intervention critical for sustained recovery	Strategies should include stress coping, early cessation mechanisms
Fareed et al. 2009 [15]	2002-2007	Atlanta, USA	Retrospective chart review	Methadone maintenance patients (N=91)	Above 60 years	Examined treatment history, comorbid alcohol misuse	Older individuals had longer treatment periods and less current heroin use	Reduction in drug use, psychiatric, medical, and legal problems	Target lifestyle risk factors and comorbid conditions for intervention
Rajaratnam et al. 2009 [25]	Not given	New York, USA	Random selection using stratified sampling	Methadone treatment patients (N=156)	Above 60 years	Examined treatment duration, history of alcohol misuse	Older individuals more likely to have longer treatment periods	Less current heroin use, overall drug use reduced	Better preparedness for methadone maintenance services needed
Moy et al. 2011 [26]	Publications up to January 2007	Not applicable	Systematic review	Individuals over 50 years with any substance disorder (N=varied)	Above 60 years	Evaluated treatment responses among older individuals	Encouraging treatment responses among older individuals	Lack of studies on illicit drug use treatments	Need for increased research and development of health services for older individuals
Hser et al. 2001 [27]	1974-1997	California, USA	Longitudinal study	Original N=581 male heroin addicts	Above 60 years	Followed heroin addicts for over 30 years	Identified groups with distinct heroin use trajectories	Persistent heroin use into the late 50s	Early intervention and long-term management strategies required
Firoz and Carlson 2004 [28]	1995-2000	Midwest, USA	Prospective cohort study	Methadone maintenance patients (N=759)	Above 60 years	Examined medical and psychiatric problems, employment	The older group had improved outcomes on drug use measures	Similar medical and psychiatric problems as younger patients	Methadone programs should consider the unique needs of older patients
Doukas 2014 [29]	2000-2014	Various	Literature review	Older individuals prescribed methadone (N=varied)	Above 60 years	Reviewed lifespan from opiate initiation to MMT	Increase in comorbid conditions with age	Chronic pain and psychiatric issues prevalent	Need for comprehensive care models tailored to the elderly
Fahmy et al. 2012 [30]	2007-2010	United Kingdom	Cross-sectional survey	Individuals aged 60+ using illicit drugs (N=500)	Above 60 years	Prevalence of drug use in older individuals	Higher rates of prescription drug misuse	Opioids and benzodiazepines are frequently misused	Public health interventions needed for older individuals
Outlaw et al. 2012 [31]	2000-2010	Various	Systematic review	Older individuals with substance problems (N=varied)	Above 60 years	Treatment outcomes for older individuals	Better outcomes in older individuals compared to younger ones	Consistent with reduced drug use and improved health	Age-specific treatment protocols recommended
Teesson et al. 2015 [13]	2001-2012	Australia	Long-term cohort study	Heroin-dependent individuals (N=615)	No specific cut-off for "older"	Mortality and remission rates	High mortality among older heroin users	Long-term follow-up critical for intervention success	Integration of mental health and addiction services
Pirona et al. 2015 [32]	2000-2015	Europe	Policy review	Aging opioid users in treatment (N=varied)	Above 60 years	Challenges for treatment systems	An increasing number of older opioid users	Need for policy adjustments to meet aging population needs	Enhanced support systems and funding required