Drug and Alcohol Dependence, 10 (1982) 383 - 391 383

PREDICTION OF LONG-TERM OUTCOME FOR HEROIN ADDICTS ADMITTED TO A METHADONE MAINTENANCE PROGRAM

BARBARA A. JUDSON and AVRAM GOLDSTEIN

Addiction Research Foundation, Palo Alto, California 94304 (U.S.A.)

(Received October 5, 1982)

Summary

Ten pre-treatment and nine during-treatment variables were correlated to outcome 5 years after admission to a methadone program for 171 subjects who were in treatment for at least 6 months. The pre-treatment variables were employment, education, criminal involvement, opiate and non-opiate drug abuse, periods of abstinence, age, sex, and ethnic group. During-treat- ment variables were employment, arrests or incarcerations, opiate and non- opiate drug abuse, living with an addict, marital status, and months of me- thadone treatment. Three measures of ‘successful’ outcome were defined. In general, subjects with more involvement with criminal justice before treat- ment, heavy alcohol use before or during treatment, continued daily heroin use or living with an addict during treatment, or minority ethnicity were more likely to have a poor outcome. However, the correlation coefficients for even the most significant correlations were weak; the highest was r = 0.26. We conclude that none of these 19 variables provide a basis for a priori judg- ment about whether or not a patient applying for admission to a methadone program is likely to have a favorable long-term outcome.

Introduction

When a heroin addict presents himself or herself for methadone treat- ment, it is of interest to know if there are predictors of outcome. Some patients will drop out quickly, others will remain in treatment for years. Some will rapidly relapse to a pattern of frequent heroin use, others will abstain for prolonged periods. Is there any way to tell, at admission, which type of patient will succeed and which will fail? Years later, we all know, some have done extraordinarily well, indeed have put the addict life-style and heroin use behind them. For others, methadone treatment is merely a passing phase, without much influence on their life-styles or drug abuse patterns. If one could tell from admission history or from progress during treatment if a

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patient was likely to have a good or bad outcome, perhaps treatment inter- vention could be tailored more specifically to that patient. In the present study we examine the correlation between various possible predictors of success and several outcome measures 5 years after admission to treatment. We found no very useful predictors of treatment success.

Method

The data used here are from 171 subjects interviewed 5 years after starting treatment in the Santa Clara County (California) methadone main- tenance treatment program. This group was from a random sample of 188 of the first 799 patients admitted when the program began in 1970, 17 having been excluded because they were in methadone treatment less than 6 months. Results of the 5-year follow-up study and descriptive data on the random sample have been presented [ 11. During the 5-year follow-up interview, information was obtained on drug use, employment, living situation, marital status, arrests and imprisonments, education, treatments for drug abuse, age, sex, and ethnicity. The information was gathered retrospectively, as a life history, from age 12 (or first drug use) to the time of interview. Data were recorded on a calendar year basis, unless the subject could remember specific months when events and activities occurred or changed. A ‘most-of-the-year’ rule was generally applied. Thus, if a status or activity occurred during six months or more of a calendar year, it was entered for that year, otherwise not. However, a more conservative criterion was applied to arrests or incar- cerations and to heroin use. Even a single arrest or incarceration was entered; and daily heroin use for a month or more was entered as daily use for the entire calendar year. In general, subjects could remember activities or events on a monthly basis only during the year or so prior to the follow-up inter- view. Information that referred to the pre-treatment or treatment period was checked against treatment files, and was corrected if the discrepancy from the subject’s recollection was well documented.

The data gathered in these interviews were divided into two distinct periods: the first, or variable duration, from age 12 (or first drug use) to the time of admission to treatment; and the second, of approximately 5 years, from admission to the time of the follow-up interview. The mean elapsed time after the 5-year anniversary date of entering the program at which inter- views were done was 2.7 months (median 1 month, range 1 to 28 months). For the first period, we considered 10 pre-treatment variables: months of heroin use since first daily use; months abstinent from heroin while at risk in the community (since first daily use); months employed; months in school; months of heavy alcohol use’; number of arrests; months in jail or prison; age at admission; sex; and ethnicity.

’ Defined as five or more drinks daily, or 12 or more drinks daily 3 4 times a week. One drink is considered to be 12 oz. beer, 4 oz. wine, or 1.5 oz. distilled spirits.

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The 5-year period between admission to methadone treatment and the follow-up interview was divided into periods in treatment and periods not in treatment. For the years during which the subject was in treatment 6 months or more, nine during-treatment variables were considered. Seven of these were based on percent of time for the following activities: employment; living with an addict; incarceration; daily heroin use; heroin use less than daily (‘chipping’); heavy alcohol use’; and heavy use of non-opiate drugs2. The other two during-treatment variables were months of methadone treatment and whether or not married (including common-law marriage).

When recalling past events, people tend to organize their memories by calendar year, according to the conventional time markers such as seasons, months, and holidays. The follow-up life-history interview was therefore structured by calendar year. For data analysis, however, we wished to com- pare subjects over comparable periods of time with respect to treatment, such as the year prior to admission, or the year prior to interview (i.e., the 5th year after admission). The transformation was carried out according to the same ‘most of the year’ rule as in the original data collection, and with the same exceptions, i.e., a month or more of daily heroin use was coded as daily use for the entire calendar year, and each arrest or incarceration was recorded.

Three definitions of ‘success’ were used as dependent variables, and were correlated with the pre-treatment and during-treatment variables:

(a) Abstinent Since Treatment (AST). Seventeen subjects who had no heroin use, arrests, or incarceration time, or admissions to any treatment program for drug abuse since leaving methadone treatment (mean If: SEM = 2.2 + 0.3 yr, range 1 - 5 yr) were compared to the 123 subjects who had used heroin or had an arrest or incarceration during the year prior to inter- view. The remaining 31 subjects (of the 171 in the sample) were abstinent from opiates at follow-up, but had not been abstinent for the whole time since leaving treatment.

(b) Heroin Score (HS). Heroin use during the year prior to the follow- up interview was scored as follows: 0 = no use most of the year; 1 = some use, less than daily for 6 months or more; 2 = daily use for one month or more. Of the 171 subjects, 24 who were incarcerated 6 months or more of this year (and therefore not ‘at risk’) were excluded.

(c) Global Outcome Score (GOS). This is a total score for the year prior to the follow-up interview, based on the following arbitrary partial scores:

‘See footnote 1, page 384.

2 Defined as follows: barbiturates and tranquilizers, 20 or more pills 3 - 4 times or more per week; amphetamines, $40 or more spent daily 3 - 4 times or more per week;

marijuana, 20 or more ‘joints’ 3 - 4 times or more per week.

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Daily heroin use for one month or more

(Alternatively): Less than daily heroin use, most of year

Living with an addict, most of year

Arrest (no incarceration) during year

Incarceration, number of months x 3 (minimum score 10)

Unemployed, most of year In treatment for drug abuse, ever during year

Heavy alcohol use, most of year (see footnote 1, p. 384)

Heavy use of non-opioid drugs, most of year

(See footnote 2, p. 385)

Possible range of scores

20

10

10

10

10 - 36 5

5

5

5

0 -96

Data analysis was carried out as follows. Since the number of patients belonging to ethnic groups other than Caucasian or Spanish-surname was very small (4% Black, 3% other), they were eliminated from the analysis of ethnicity and outcome. Subjects abstinent since leaving treatment (AST) were compared to those with heroin use or arrest or incarceration in the year prior to interview by means of Wilcoxon two-sample rank tests for all continuous variables, chi-square analysis for discrete variables (marital status, sex, ethnicity). The relationship between heroin scores (HS) or global out- come scores (GOS) on the one hand, and pre-treatment or during-treatment continuous variables on the other, was estimated by Spearman rank correla- tions. For discrete variables (marital status, sex, ethnicity), Wilcoxon two- sample rank tests were done. ‘Statistical significance’ was defined asp < 0.05.

Results

Analysis 1 This analysis compared the best outcomes with the worst: subjects

abstinent and without arrests or incarceration since leaving treatment (AST group, N = 17) versus subjects who used heroin or were arrested or incarcer- ated during the previous year (N = 123). In the pre-treatment period, the AST group had differed significantly in the following respects but in no other:

(a) Less criminal activity, as measured by the number of times arrested or incarcerated or by the total time incarcerated (p < 0.05);

(b) Less heavy alcohol use (p < 0.05); (c) More likely to be of Caucasian ethnicity (p < 0.01). During treatment, the AST group had significantly less daily heroin use

0, < 0.05).

Analysis 2 This analysis examined the within-subjects correlation for 147 subjects

between heroin scores (HS) during the year prior to interview and all the pre- treatment and during-treatment variables. This analysis excluded 24 subjects who were incarcerated for 6 months or more during that year. No significant correlations were found with pre-treatment variables, and the only during-

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treatment variable significantly correlated with HS was daily heroin use (r = 0.22, p < 0.01). A separate analysis for 65 subjects who had not been incar- cerated and also had no treatment for drug abuse during the year prior to interview revealed no significant correlations at all.

Analysis 3 Finally, this analysis examined the within-subjects correlation of global

outcome score (GOS) with the pre-treatment and during-treatment variables. For the total sample of 171, total time incarcerated during the pre-treatment period was significantly and positively correlated with GOS (r = 0.18, p < 0.05), i.e., the more time incarcerated before treatment, the worse the even- tual outcome. Subjects of Caucasian ethnicity were more likely 0) < 0.01) to have lower GOS. Of the during-treatment variables, the significant correla- tions were living with an addict (r = 0.26, p < 0.01); daily heroin use (r = 0.19, p < 0.02); arrests or incarcerations (r = 0.19, p < 0.02); and heavy alcohol use (r = 0.17, p < 0.05). For the special subset of 65 subjects (see analysis 2 above), heavy alcohol use in the pretreatment period correlated significantly (r = 0.24, p = 0.05) with GOS. As in the analysis of the total group, subjects of Caucasian ethnicity were significantly more likely to have a better outcome (p < 0.05) than those with Spanish surnames. No significant correlations were found with the during-treatment variables.

Comparison of pre-treatment variables of the 17 subjects who dropped out of methadone treatment in less than 6 months and the 171 who had 6 months or more of treatment showed that the 17 differed only in having significantly fewer months of employment (p = 0.01).

Discussion

The results of this investigation indicate that for a heroin addict who remained in methadone treatment at least 6 months, there were three predic- tors of a poor outcome 5 years later. These were heavy alcohol use and crim- inal activity (as measured by the number or durations of incarcerations) in the pretreatment period, and minority ethnicity (Spanish surname). During the treatment period, continued daily heroin use, heavy alcohol use, and living with an addict were the only predictors of a poor outcome.

Previous follow-up studies of methadone patients have produced vari- ous, and often contradictory, predictors of successful outcome. In a study of 38 successfully detoxified patients, Riordan et al. [ 21 found that the group who were opiate-abstinent at follow-up were more likely to have been unem- ployed, and to have had a shorter course of addiction, more involvement with criminal justice, and less education in the pre-treatment period than the group of patients who relapsed. The opiate-abstinent patients were also more likely to be Black and had been maintained on methadone longer than those who relapsed.

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Pugliese et al. [ 31 compared patients who detoxified from methadone maintenance with staff consent (group 1) and without staff consent (group 2). Of the group 1 patients, 80% were opiate-abstinent at follow-up, compared to only 10% in group 2. Group 1 patients had a shorter history of incarcera- tion prior to admission to the program than did group 2 patients, and had a higher rate of employment and fewer heroin-positive urine tests while in treatment. Patients in group 1 were in treatment nearly twice as long as those in group 2.

Stimmel et al. [4] did a multivariate analysis of return to narcotic use after detoxification, using the following admission variables: age, sex, family composition, education, employment status, and years of drug use. Reason for detoxification (with or without staff approval, jail, violation of rules), and time in treatment were also used in the analysis. The results showed that the most important variable in estimating risk of relapse was reason for detox- ification, with patients not completing treatment running a 5fold higher risk of relapse than patients who completed treatment. Lower age at admission and shorter duration of treatment were significantly but less importantly related to relapse.

Smart et al. [ 5 ] found employment at admission to be positively corre- lated with a favorable outcome at follow-up, and Simpson [6] reported that employment in the post-treatment period was associated with lower opioid drug use and less criminal involvement.

Employment during treatment, absence of behavioral problems during treatment, and time in treatment were positively correlated with opiate abstinence in the three-month period prior to follow-up in Dole and Joseph’s study [ 71, while duration of heroin use and criminality in the pre-treatment period were positively and significantly correlated with relapse.

In a follow-up evaluation of patients admitted to methadone programs which were part of DARP (Drug Abuse Reporting Program), Simpson et al. [ 81 reported that favorable outcome after treatment was significantly related to older age at admission, less pre-treatment criminality, less during-treatment social deviance, and longer time in treatment.

Cushman [9], on the other hand, found no relationship of outcome to time in treatment in a group of therapeutically detoxified patients (suppor- tive detoxification with staff approval). As in the study of Stimmel et al. [4], a considerable time in treatment was prerequisite to staff approval Nor was outcome related to duration of addiction before treatment, manifest alco- holism before or during treatment, or marital status at the completion of detoxification. Patients who were employed during detoxification were more likely to have a favorable outcome.

In a second follow-up study of several New York methadone programs, Cushman [lo] did find an effect of treatment duration on outcome at follow- up, with methadone treatment of at least 3 years duration being more often associated with successful outcome than were shorter durations of treatment. Again, steady employment during treatment was strongly associated with favorable outcome.

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Des Jarlais and Joseph [ 111 found a strong positive correiation between alcohol use at admission and alcohol use during treatment, and also between alcohol use during treatment and after discharge. However, they found no relationship between alcohol use and opiate use for any of the time periods.

In 1962 Winick [12] advanced a theory based on arrest records of known addicts, that a ‘maturing-out’ process occurred, i.e., that heroin ad- dicts tended to give up heroin as they got older. Several other studies pro- vided evidence that supported this view [ 13 - 161, but few follow-up studies of methadone patients have found a relationship between cessation of heroin use and age.

Whitman et al. [17], in a 5-year prospective follow-up study of non- prisoner admissions to the Clinical Research Center at Lexington, Kentucky, found no pre-treatment or ‘current-state’ (at follow-up) variables that were related to relapse or opiate abstinence after leaving treatment. Pre-treatment variables examined were education; criminal history; psychiatric family his- tory; ‘dependence process’ variables (e.g., job problems, overdoses, family problems, hospitalizations, legal problems, length of addiction); age; sex; and ethnicity. ‘Current-state’ variables included employment; marital status; children; craving for opiates; recent losses of family or friends; and loss of control. Duration of treatment was also included in the analysis.

In the present study various pre-treatment variables often considered to be predictive of treatment success or failure were found to have no pre- dictive value. Among these were employment status, total previous amount of heroin use, and age. Among the during-treatment variables it is interesting that employment status, marital status, arrests or incarcerations, use of non- opioid drugs, and even occasional heroin use were without value in predict- ing outcome.

Duration of methadone maintenance treatment had no relationship to outcome. However, this should not be misinterpreted. Some patients who leave treatment early are responding poorly (e.g., are continuing to use heroin, or are terminated for disciplinary reasons), but others are doing well and detoxify deliberately in order to attempt abstinence. Moreover, in this methadone program, patients were encouraged to detoxify when they felt the time was ripe, and they were guaranteed immediate readmission if relapse to heroin use occurred. The resulting mixed pattern of motivation for early termination may account for the lack of a relationship between treatment duration and ultimate outcome.

We draw the following conclusions from this study: (a) No a priori judgments should influence the decision to admit an

applicant for methadone maintenance treatment, since there are so few pre- dictors of outcome. Even the few predictors that are statistically significant are weak. Thus, even for the highest correlation coefficient found here (r = 0.26), only 7% of the variance would be accounted for by the correlation; consequently, the prediction would be wrong nearly as often as by chance.

(b) A history of heavy alcohol use, or heavy drinking during treatment, are warnings of poor global outcome as well as of poor outcome from the

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standpoint of abstinence from heroin. This suggests that the alcohol problem should be dealt with at the same time as the heroin problem, perhaps by giving disulfiram (Antabuse), when indicated, together with the daily me- thadone.

(c) Since criminal activity, as measured by number and duration of incarcerations, was a predictor of poor outcome, one could argue that with facilities and budgets limited, effort should be concentrated on those without a criminal background, who are most likely to benefit. The contrary argu- ment could be made that rehabilitative efforts should be concentrated on those with the worst criminal records; but there is no evidence as to whether or not such efforts would be effective. From the standpoint of maximum benefit to society, attempts should certainly be made to retain the worst criminals in methadone treatment, since the evidence is strong that their total crimes and the dollar value of their crimes decrease when their use of heroin decreases [18 - 211.

(d) That living with an addict during treatment was predictive of poor outcome confirms common sense clinical judgment, which holds that both members of an addicted couple should be treated simultaneously.

Acknowledgement

This investigation was supported by grant DA-973 from the National Institute on Drug Abuse.

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