Journal of Substance Abuse Treatment, Printed in the USA. All rights reserved.
Vol. 9, pp. 319-325,
1992 Copyright
0
0740-5472/92 $5.00 + .OO 1992 Pergamon Press Ltd.
ARTICLE
Crack Cocaine Use in a Cohort of Methadone Maintenance Patients DON C. DES JARLAIS, PhD,* JOHN WENSTON, MA,? SAMUEL R. FRIEDMAN, phD,t Jo L. SOTHERAN, MA,? ROBERT MASLANSKY, MD,$ AND MICHAEL MARMOR, PhD$ *Beth Israel Medical
Center, New York, New York; tNarcotic and Drug Research, Inc., New York, New York; SBellevue Hospital, Addiction Treatment Center, New York, New York; $New York University, School of Medicine, New York, New York
We examined crack use in a cohort of methadone patients originally enrolled in 1984-86. Crack use questions were added to the study in 1987. Of the 494 methadone patients originally enrolled, 228 subjects remained in methadone and were re-interviewed in 1987-88, and 234 remained in methadone and were re-interviewed in 1988-89. Approximately one-quarter of the subjects were using crack at each of the 1987-88 and 1988-89 data collection points, and only 3% of the subjects were using crack at daily or greater frequencies at each of the 1987-88 and 1988-89 interviews. Concurrent crack use was associated with (a) the number of noninjected drugs being used; (6) the number of IVdrug-using sexual partners; (c) drug injection; and(d) the use of nonheroin opiates. Persistent crack use, defined as use in both 1987-88 and 1988-89, was associated with previous noninjected drug use andprevioussuicide attempts. While thepotentialproblem of crack use among methadone patientsshould not be minimized, it appears that, compared to illicit drug injectors not in treatment, being in methadone maintenance may offer a protective effect against crack use. Abstract-
Keywords-crack;
cocaine;
methadone;
AIDS; polydrug.
dency of IDUs to use a wide variety of noninjected drugs (Hubbard et al., 1989), so that IDUs must be considered to be at particularly high risk of developing problems with crack. The high prevalence of HIV infection among persons who have injected illicit drugs is of particular importance for public health. Most of the intravenous drug users who have been exposed to HIV were exposed through the sharing of drug injection equipment, while sexual transmission has been a distinctly secondary route of transmission (see Turner, Miller, & Moses, 1989). Yet because of its association with high levels of unsafe sexual activity, crack use may both increase the rate of heterosexual HIV transmission among IDUs themselves and greatly increase heterosexual transmission from IDUs to persons who do not inject illicit drugs. There have been a limited number of studies of the relationships between crack use and intravenous drug use. First, at least in New York City, the emergence of crack has not led to a large-scale substitution of smoking cocaine for injecting cocaine (Des Jarlais & Fried-
INTRODUCTION THE USE OF CRACK COCAINE has been associated with recent increases in syphilis (Rolfs, Goldberg, & Sharrar, 1990), high levels of unsafe sexual activity (Friedman et al., 1988), failure of mothers to properly care for children (Beckwith, Rodning, & Kropenske, 1989), and sexual transmission of human immunodeficiency virus (the causative agent for AIDS) (Chiasson et al., 1989). The distribution of crack has been associated with an increase in violent crimes (Goldstein, Brownstein, Ryan, & Bellucci, 1989). Persons with histories of injecting illicit drugs are a particularly important group to study with respect to crack use. Many injecting drug users (IDUs) have not been able to control their use of illicit drugs, and there is an increasing tenThis research was supported by grant DA03574 from the National Institute on Drug Abuse. The views expressed in this paper do not necessarily reflect the positions of the granting agency or of the institutions by which the authors are employed. Requests for reprints should be sent to Don C. Des Jarlais, c/o BIMWNDRI, 11 Beach Street, New York NY 10013.
319
320
D. C. Des Jarlais et al.
man, 1988), even though crack use does not involve the pain and direct threat of HIV exposure that are associated with injecting illicit drugs. Crack should therefore be seen as an additional form of drug use rather than as a replacement for injecting. Second, studies of intravenous drug users not in treatment (Des Jarlais, 1990; Weissman, Sowder, &Young, 1990) have shown crack use (and high levels of unsafe sexual activity) among persons with long histories of injecting illicit drugs. These studies have not yet provided longitudinal data on crack use among intravenous drug users, either at the individual or group level, nor have they identified factors associated with continuing crack use among intravenous drug users. The present study examines the extent of crack use in a cohort of intravenous drug users in methadone maintenance treatment and identifies predictors of persistent crack use among the group. METHODS A cohort of 494 injecting drug users was recruited from
methadone maintenance and inpatient drug detoxification programs in 1984 through 1986. The purpose of the cohort study was to examine risk factors for AIDS among injecting drug users. Details on recruitment and follow-up for the cohort have been presented elsewhere (Marmor et al., 1987; Des Jarlais et al., 1987; Des Jarlais et al., 1989). For the purposes of the present study, some additional methodological comments are required. First, the present study is confined to subjects who were enrolled in methadone treatment when the study began and who remained in methadone treatment throughout the study period. Second, subject recruitment was a convenience sample rather than a random sample of methadone patients. Third, in order to process blood samples on the day of collection, recruitment was conducted primarily from mid-morning to early afternoon. Consequently, there was underrepresentation of patients who attended the clinics less frequently as well as of patients who only attended very early in the morning or in the evening. The effects of this recruitment strategy on the generalizability of the findings are considered in the discussion section. Participation in the study was voluntary, and individual research information was not shared with staff of the treatment program unless the subject specifically agreed that information be shared (usually in the context of providing medical treatment for HIV-related disease). Informed consent was obtained, an interview covering AIDS risk behaviors and medical history was administered by a trained interviewer, and a 25mL blood sample was collected at each data collection point, which occurred approximately once per year after intake into the study. A high percentage of the patients who were asked to participate- over 95% agreed to do so. Within the interview format each sub-
ject was asked about drug use and AIDS risk behaviors either over the previous two years (on the intake interview) or since the subject’s last study interview (on the follow-up interviews). Some questions, including a three-item depression scale, were added to the intake interview for subjects enrolled in 1986. Questions on crack use were added to the follow-up interviews beginning in 1986-87, but were not included on the intake interviews. The self-reported drug use and sexual behavior of subjects in this study have been associated with HIV exposure in theoretically predicted ways (Marmor et al., 1987), suggesting that the self-report data are valid for the subjects as a group. Of the 494 methadone patients enrolled in the cohort from 1984 to 1986, 228 remained in methadone treatment and were re-interviewed in 1987-88, and 234 remained in methadone treatment and were re-interviewed in 1988-89, with 166 participating in both of these follow-up interviews. (That some subjects in the cohort could not be interviewed in one year but were then successfully interviewed in a later year is not unusual for cohort studies of intravenous drug users.) Substantial numbers of subjects who had left methadone treatment were also re-interviewed in 1987-88 and 1988-89, but are not included in the analyses presented here. These subjects included persons who had been doing “very well” in treatment and detoxified with program approval and others who had been doing “very poorly” and were administratively discharged or left against medical advice. Proper analyses of crack use among subjects who had left methadone treatment would thus have required stratification by reason for leaving, which would have greatly reduced statistical power. For the subjects included in this paper, there was a mean of 22.3 months (median 22.1 months) between the “previous” interview and the follow-up 1987-88 interviews (which had the first questions specific to crack use) and a mean of 13.0 months (median 11.5 months) between the 1987-88 and 1988-89 follow-up interviews. The 1987-88 follow-up interviews therefore asked about crack use over the previous 2-year period, while the 1988-89 follow-up interviews asked about crack use over the previous l-year period. It was during this time period - 1985 to 1989 -that crack use was rapidly increasing in New York City. Since that time crack use appears to have stabilized or slightly declined in 1989 and 1990 (Johnson & Hamid, 1990). The data reported in this study thus should cover the period of the great increase in crack use in New York. RESULTS
Table 1 presents demographic characteristics of the methadone maintenance subjects re-interviewed in 1987-88 and 1988-89. The demographic changes pri-
321
Crack and Methadone Maintenance TABLE 1 and Drug Characteristics Follow-Up Sample
of
1987-88
1988-89
Follow-Up (n = 228)
Follow-Up (n = 234)
37.8
39.5
67% 33%
73% 27%
36% 28% 36% 0% 47% 17.6 6% 43%
37% 30% 32% 1% 43% 19.4 1% 47%
Mean age in years Sex Male Female RacelEthnicity White Blat k Hispanic Other HIV positive Mean years since first injection Injecting 5 years or less No injections since last interview
marily reflect aging of the cohort, with a higher mean age and fewer new injectors (persons who had injected for less than 5 years). With a mean of 18 years since first injecting drugs, this group of subjects should be considered highly experienced users of illicit drugs. Frequency of crack cocaine use since the previous interview for the 1987-88 and 1988-89 subjects is presented in Table 2. For both times, approximately onequarter of the subjects reported using crack, although only a small minority reported high frequencies of crack use. To identify factors associated with crack use among this cohort of intravenous drug users, we first Iooked for concurrent associations between variables from the 1987-88 interviews and self-reported crack use during the same time period (approximately the previous 2 years). Tables 3 and 4 present the variables that were
TABLE 2 Frequency of Crack Cocaine Use In Follow-Up Periods
Never Once a year Once a month 1-3 times per ~nth Once a week 2-3 times per week 4-6 times per week Once a day 2-3 times daily 4 or more times a day
1987-88 Follow-Up Sample (n = 228)
1988-89 i=ollow-up Sample (n = 234)
78% 4%
75% 6% 6% 1% 1% 3% 3% 0% 1% 2%
z; 3% 2% 0% 1% 2% 0%
associated with any self-reported use of crack in univariate analyses. No demographic variables were associated with crack use, but the concurrent use of a large number of other drugs was associated with crack use. Two measures of sexual behavior - the number of regular partners who were known to have injected drugs, and engaging in prostitution (defined as exchanging sex for money or drugs) - were associated with using crack. Of the 15 subjects who reported engaging in prostitution in the period covered by the 1987-88 interview, 10 were female, 4 were male, and 1 was a transsexual. Crack use was particularly high among the 9 females who engaged in prostitution and injected drugs; 6 of these women also used crack. The use of condoms was not associated with crack use (data not presented). HIV status also was not associated with crack use; 49% of the crack users were seropositive and 480/, of the non-crack users were seropositive. In a stepwise multivariate logistic regression analysis of predictors of crack use in the 1987-88 interview data, we first entered the number of noninjected drugs (other than crack) used since the previous interview, and then added use of individual drugs. Results of the multivariate logistic regression for factors associated with crack use during the 1987-88 time period are presented in Table 5. There were four statistically significant independent factors associated with concurrent crack use- three referring to other drug behavior and one representing close interpersonal relationships with other drug users. To examine crack use over time in this cohort, we first determined whether crack use in 1987-88 was associated with re-interviewing the subject in 1988-89, There was a significant relationship -only 622%(3 I /50) of the subjects reporting crack use in 1987-88 remained in methadone treatment and could be re-interviewed the following year, while 78% (138/178) of the subjects reporting no use of crack in 1987-88 remained in treatment and could be re-interviewed in 1988-89 (x2 = 4.907, p < 0.03). (The relationship between crack use in 1987-88 and lack of a follow-up interview in 198889 also held when we included the persons who were followed up but were not in methadone programs at the time of follow-up. Data not presented.) The 198889 interviews thus probably underrepresent persons who continued to use crack in the time period between the interviews. Table 6 presents a cross tabulation of the frequencies of crack use for the 166 subjects who were in methadone maintenance and interviewed at both time intervals. Overall, there was relative stability in the use of crack among these subjects, without a strong trend towards escalation of use of crack. Of these 166 subjects, 125 (75%) reported using crack at the same frequency, while 24 (14%) subjects reported increasing their frequency of crack use, and 17 (10%) subjects reported decreasing their use. The number of subjects
322
D. C. Des Jarlais et al. TABLE 3 Comparison of Crack Users With Nonusers-1997-I
Sexual and Drug-Related Risk Behaviors Drugs used IV Any IV drug Any speedball Any heroin Any cocaine Non-IV drugs used Any drug Heroin -snorted Cocaine-snorted Other opiates Barbiturates Other sedatives Marijuana PCP Psychedelics Clonidine Elavil Alcohol Mean number of non-IV drugs used Mean time since last injection (mos.) Sexual activity Prostitution All subjects IVDU femalesb Mean no. IVDU partners Any sharing of syringes
Crack Users (n = 50)
989 Follow-Up Sample
Nonusers (n = 178)
p valuea
80% 44% 30% 68%
51% 18% 16% 44%
0.000 0.000 0.030 0.003
90% 20% 38% 26% 8% 14% 64% 8% 6% 18% 40% 58% 2.3 18.8
75% 8% 24% 4% 1% 5% 38% 0% 1% 7% 15% 36% 1.2 45.5
0.021 0.021 0.042 0.000 0.022 0.025 0.001 0.002 0.034 0.024 0.000 0.005 0.002 0.000
16% 55% 1.04 41%
4% 10% 0.48 26%
0.006 0.002 0.006 0.049
Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test
t test t test
Fisher’s Exact Test
t test
aAll significance tests are chi-square unless noted otherwise. bn = 11 crack users; n = 30 nonusers.
who began using during this follow-up period (19) was only slightly higher than the number of subjects who reported ceasing use of crack (12). These 12 who did not use crack during the follow-up period represent 39% of the 31 subjects using crack during the first period and re-interviewed in 1988-89. The factors associated with current crack use in 1987-88 provide at most limited inferences about potential causal mechanisms through which a methadone patient might initiate and continue crack use. In order to find predictors of persistent crack use, we examined the relationships of the intake data collected in 198486 with persistent crack use during 1987-89. Persistent crack use was operationally defined as reported use of crack at both the 1987-88 and 1988-89 interviewsthere were 18 subjects (8%) who met this definition. The variables examined as potential predictors included demographics, the number of noninjected drugs used, specific noninjected drugs used, specific individual drugs injected, sexual behavior, AIDS risk behaviors, HIV status, and a 3-item depression scale that was added to the questionnaire for subjects entering the study in 1986. The depression scale was associated with persistent crack use from 1987-88 and 1988-89. Analysis of the separate items in the scale showed that the question on
“feeling depressed in the previous year” was not associated with persistent crack use, but the items “having thought about suicide in the previous year” and “having attempted suicide in the previous year” were both associated with persistent crack use. Thus, it was only more severe depression, with suicidal ideation or attempts, that was associated with persistent crack use in this sample. Results of two stepwise multivariate logistic regressions are presented in Table 7; the first for subjects who entered the study in either 1984 or 1986 and using only the variables that were on both questionnaires; and the second only for subjects who entered the study in 1986. In this second analysis, all behavioral intake variables (including the depression scale) were utilized. The number of noninjected illicit drugs used at intake was a statistically significant predictor of persistent crack use in both analyses, and actually having attempted suicide was a significant predictor of persistent crack use for the subjects who entered the study in 1986.
DISCUSSION
Crack cocaine was used by approximately one quarter of the methadone patients in this sample. The use of
Crack and Methadone Maintenance
323 TABLE 4 Predictors of Crack Use-1967-l YES
IV Drugs used Any IV drug Speedball Heroin Cocaine Non-IV drugs used Any drug Heroin -snorted Cocaine -snorted Other opiates Barbiturates Other sedatives Marijuana PCP Psychedelics Clonidine Elavil Alcohol Sexual activity Prostitution All subjects IVDU females Shares needles
988
NO
n
% Use Crack
n
130 54 44 112
30% 41% 34% 30%
174 184 116
10% 16% 19% 14%
0.000 0.000
178 25 61 20 6 15 100 4 4 21 47 93
25% 40% 31% 65% 67% 47% 32% 100% 75% 43% 43% 31%
50 203 167 208 222 213 128 224 224 207 181 135
10% 20% 19% 18% 21% 20% 14% 21 % 21% 20% 17% 16%
0.021 0.021 0.042 0.000 0.022 0.025 0.001 0.002 0.034 0.024 0.000 0.005
15 9 66
53% 67% 30%
210 32 158
20% 16% 18%
0.006 0.006 0.049
96
% Use Crack
p valuea
0.030 0.003
Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test
Fisher’s Exact Test Fisher’s Exact Test
aAll significance tests are chi-square unless noted otherwise
TABLE 5 Use of Crack by Respondent Characteristics - 1987-88 Sampie, N = 228 -Results of Logistic Regression Procedure
Beta
X2
Odds Ratio
95% Cl
-3.11 0.38 0.43 1.19 1.30
48.58 5.59 4.28 8.37 4.51
1.46 1.54 3.28 3.68
1.07-I .99 1.02-2.31 1.47-7.34 1.11-12.26
Wald
Intercept Number of non-IV drugs used= Number of IVDU sexual partnersb Injecting any drugs since last interview Other non-IV opiate use since last interview
P 1 /MO.
116 7 3 1 1
14 6 1 1 0
l -4lMo. 2 0 1 0 1
2-6/Wk. 2 0 2 1 2
1 +/Day 1 3 0 0 1
324
D.C. Des Jarlais et al. TABLE 7 Prediction of Continuing Crack Use-Results Beta
of Logistic Regression Procedure
Wald x2
Odds Ratio
95%
Cl
P
Vol. 9, pp. 319-325,
1992 Copyright
0
0740-5472/92 $5.00 + .OO 1992 Pergamon Press Ltd.
ARTICLE
Crack Cocaine Use in a Cohort of Methadone Maintenance Patients DON C. DES JARLAIS, PhD,* JOHN WENSTON, MA,? SAMUEL R. FRIEDMAN, phD,t Jo L. SOTHERAN, MA,? ROBERT MASLANSKY, MD,$ AND MICHAEL MARMOR, PhD$ *Beth Israel Medical
Center, New York, New York; tNarcotic and Drug Research, Inc., New York, New York; SBellevue Hospital, Addiction Treatment Center, New York, New York; $New York University, School of Medicine, New York, New York
We examined crack use in a cohort of methadone patients originally enrolled in 1984-86. Crack use questions were added to the study in 1987. Of the 494 methadone patients originally enrolled, 228 subjects remained in methadone and were re-interviewed in 1987-88, and 234 remained in methadone and were re-interviewed in 1988-89. Approximately one-quarter of the subjects were using crack at each of the 1987-88 and 1988-89 data collection points, and only 3% of the subjects were using crack at daily or greater frequencies at each of the 1987-88 and 1988-89 interviews. Concurrent crack use was associated with (a) the number of noninjected drugs being used; (6) the number of IVdrug-using sexual partners; (c) drug injection; and(d) the use of nonheroin opiates. Persistent crack use, defined as use in both 1987-88 and 1988-89, was associated with previous noninjected drug use andprevioussuicide attempts. While thepotentialproblem of crack use among methadone patientsshould not be minimized, it appears that, compared to illicit drug injectors not in treatment, being in methadone maintenance may offer a protective effect against crack use. Abstract-
Keywords-crack;
cocaine;
methadone;
AIDS; polydrug.
dency of IDUs to use a wide variety of noninjected drugs (Hubbard et al., 1989), so that IDUs must be considered to be at particularly high risk of developing problems with crack. The high prevalence of HIV infection among persons who have injected illicit drugs is of particular importance for public health. Most of the intravenous drug users who have been exposed to HIV were exposed through the sharing of drug injection equipment, while sexual transmission has been a distinctly secondary route of transmission (see Turner, Miller, & Moses, 1989). Yet because of its association with high levels of unsafe sexual activity, crack use may both increase the rate of heterosexual HIV transmission among IDUs themselves and greatly increase heterosexual transmission from IDUs to persons who do not inject illicit drugs. There have been a limited number of studies of the relationships between crack use and intravenous drug use. First, at least in New York City, the emergence of crack has not led to a large-scale substitution of smoking cocaine for injecting cocaine (Des Jarlais & Fried-
INTRODUCTION THE USE OF CRACK COCAINE has been associated with recent increases in syphilis (Rolfs, Goldberg, & Sharrar, 1990), high levels of unsafe sexual activity (Friedman et al., 1988), failure of mothers to properly care for children (Beckwith, Rodning, & Kropenske, 1989), and sexual transmission of human immunodeficiency virus (the causative agent for AIDS) (Chiasson et al., 1989). The distribution of crack has been associated with an increase in violent crimes (Goldstein, Brownstein, Ryan, & Bellucci, 1989). Persons with histories of injecting illicit drugs are a particularly important group to study with respect to crack use. Many injecting drug users (IDUs) have not been able to control their use of illicit drugs, and there is an increasing tenThis research was supported by grant DA03574 from the National Institute on Drug Abuse. The views expressed in this paper do not necessarily reflect the positions of the granting agency or of the institutions by which the authors are employed. Requests for reprints should be sent to Don C. Des Jarlais, c/o BIMWNDRI, 11 Beach Street, New York NY 10013.
319
320
D. C. Des Jarlais et al.
man, 1988), even though crack use does not involve the pain and direct threat of HIV exposure that are associated with injecting illicit drugs. Crack should therefore be seen as an additional form of drug use rather than as a replacement for injecting. Second, studies of intravenous drug users not in treatment (Des Jarlais, 1990; Weissman, Sowder, &Young, 1990) have shown crack use (and high levels of unsafe sexual activity) among persons with long histories of injecting illicit drugs. These studies have not yet provided longitudinal data on crack use among intravenous drug users, either at the individual or group level, nor have they identified factors associated with continuing crack use among intravenous drug users. The present study examines the extent of crack use in a cohort of intravenous drug users in methadone maintenance treatment and identifies predictors of persistent crack use among the group. METHODS A cohort of 494 injecting drug users was recruited from
methadone maintenance and inpatient drug detoxification programs in 1984 through 1986. The purpose of the cohort study was to examine risk factors for AIDS among injecting drug users. Details on recruitment and follow-up for the cohort have been presented elsewhere (Marmor et al., 1987; Des Jarlais et al., 1987; Des Jarlais et al., 1989). For the purposes of the present study, some additional methodological comments are required. First, the present study is confined to subjects who were enrolled in methadone treatment when the study began and who remained in methadone treatment throughout the study period. Second, subject recruitment was a convenience sample rather than a random sample of methadone patients. Third, in order to process blood samples on the day of collection, recruitment was conducted primarily from mid-morning to early afternoon. Consequently, there was underrepresentation of patients who attended the clinics less frequently as well as of patients who only attended very early in the morning or in the evening. The effects of this recruitment strategy on the generalizability of the findings are considered in the discussion section. Participation in the study was voluntary, and individual research information was not shared with staff of the treatment program unless the subject specifically agreed that information be shared (usually in the context of providing medical treatment for HIV-related disease). Informed consent was obtained, an interview covering AIDS risk behaviors and medical history was administered by a trained interviewer, and a 25mL blood sample was collected at each data collection point, which occurred approximately once per year after intake into the study. A high percentage of the patients who were asked to participate- over 95% agreed to do so. Within the interview format each sub-
ject was asked about drug use and AIDS risk behaviors either over the previous two years (on the intake interview) or since the subject’s last study interview (on the follow-up interviews). Some questions, including a three-item depression scale, were added to the intake interview for subjects enrolled in 1986. Questions on crack use were added to the follow-up interviews beginning in 1986-87, but were not included on the intake interviews. The self-reported drug use and sexual behavior of subjects in this study have been associated with HIV exposure in theoretically predicted ways (Marmor et al., 1987), suggesting that the self-report data are valid for the subjects as a group. Of the 494 methadone patients enrolled in the cohort from 1984 to 1986, 228 remained in methadone treatment and were re-interviewed in 1987-88, and 234 remained in methadone treatment and were re-interviewed in 1988-89, with 166 participating in both of these follow-up interviews. (That some subjects in the cohort could not be interviewed in one year but were then successfully interviewed in a later year is not unusual for cohort studies of intravenous drug users.) Substantial numbers of subjects who had left methadone treatment were also re-interviewed in 1987-88 and 1988-89, but are not included in the analyses presented here. These subjects included persons who had been doing “very well” in treatment and detoxified with program approval and others who had been doing “very poorly” and were administratively discharged or left against medical advice. Proper analyses of crack use among subjects who had left methadone treatment would thus have required stratification by reason for leaving, which would have greatly reduced statistical power. For the subjects included in this paper, there was a mean of 22.3 months (median 22.1 months) between the “previous” interview and the follow-up 1987-88 interviews (which had the first questions specific to crack use) and a mean of 13.0 months (median 11.5 months) between the 1987-88 and 1988-89 follow-up interviews. The 1987-88 follow-up interviews therefore asked about crack use over the previous 2-year period, while the 1988-89 follow-up interviews asked about crack use over the previous l-year period. It was during this time period - 1985 to 1989 -that crack use was rapidly increasing in New York City. Since that time crack use appears to have stabilized or slightly declined in 1989 and 1990 (Johnson & Hamid, 1990). The data reported in this study thus should cover the period of the great increase in crack use in New York. RESULTS
Table 1 presents demographic characteristics of the methadone maintenance subjects re-interviewed in 1987-88 and 1988-89. The demographic changes pri-
321
Crack and Methadone Maintenance TABLE 1 and Drug Characteristics Follow-Up Sample
of
1987-88
1988-89
Follow-Up (n = 228)
Follow-Up (n = 234)
37.8
39.5
67% 33%
73% 27%
36% 28% 36% 0% 47% 17.6 6% 43%
37% 30% 32% 1% 43% 19.4 1% 47%
Mean age in years Sex Male Female RacelEthnicity White Blat k Hispanic Other HIV positive Mean years since first injection Injecting 5 years or less No injections since last interview
marily reflect aging of the cohort, with a higher mean age and fewer new injectors (persons who had injected for less than 5 years). With a mean of 18 years since first injecting drugs, this group of subjects should be considered highly experienced users of illicit drugs. Frequency of crack cocaine use since the previous interview for the 1987-88 and 1988-89 subjects is presented in Table 2. For both times, approximately onequarter of the subjects reported using crack, although only a small minority reported high frequencies of crack use. To identify factors associated with crack use among this cohort of intravenous drug users, we first Iooked for concurrent associations between variables from the 1987-88 interviews and self-reported crack use during the same time period (approximately the previous 2 years). Tables 3 and 4 present the variables that were
TABLE 2 Frequency of Crack Cocaine Use In Follow-Up Periods
Never Once a year Once a month 1-3 times per ~nth Once a week 2-3 times per week 4-6 times per week Once a day 2-3 times daily 4 or more times a day
1987-88 Follow-Up Sample (n = 228)
1988-89 i=ollow-up Sample (n = 234)
78% 4%
75% 6% 6% 1% 1% 3% 3% 0% 1% 2%
z; 3% 2% 0% 1% 2% 0%
associated with any self-reported use of crack in univariate analyses. No demographic variables were associated with crack use, but the concurrent use of a large number of other drugs was associated with crack use. Two measures of sexual behavior - the number of regular partners who were known to have injected drugs, and engaging in prostitution (defined as exchanging sex for money or drugs) - were associated with using crack. Of the 15 subjects who reported engaging in prostitution in the period covered by the 1987-88 interview, 10 were female, 4 were male, and 1 was a transsexual. Crack use was particularly high among the 9 females who engaged in prostitution and injected drugs; 6 of these women also used crack. The use of condoms was not associated with crack use (data not presented). HIV status also was not associated with crack use; 49% of the crack users were seropositive and 480/, of the non-crack users were seropositive. In a stepwise multivariate logistic regression analysis of predictors of crack use in the 1987-88 interview data, we first entered the number of noninjected drugs (other than crack) used since the previous interview, and then added use of individual drugs. Results of the multivariate logistic regression for factors associated with crack use during the 1987-88 time period are presented in Table 5. There were four statistically significant independent factors associated with concurrent crack use- three referring to other drug behavior and one representing close interpersonal relationships with other drug users. To examine crack use over time in this cohort, we first determined whether crack use in 1987-88 was associated with re-interviewing the subject in 1988-89, There was a significant relationship -only 622%(3 I /50) of the subjects reporting crack use in 1987-88 remained in methadone treatment and could be re-interviewed the following year, while 78% (138/178) of the subjects reporting no use of crack in 1987-88 remained in treatment and could be re-interviewed in 1988-89 (x2 = 4.907, p < 0.03). (The relationship between crack use in 1987-88 and lack of a follow-up interview in 198889 also held when we included the persons who were followed up but were not in methadone programs at the time of follow-up. Data not presented.) The 198889 interviews thus probably underrepresent persons who continued to use crack in the time period between the interviews. Table 6 presents a cross tabulation of the frequencies of crack use for the 166 subjects who were in methadone maintenance and interviewed at both time intervals. Overall, there was relative stability in the use of crack among these subjects, without a strong trend towards escalation of use of crack. Of these 166 subjects, 125 (75%) reported using crack at the same frequency, while 24 (14%) subjects reported increasing their frequency of crack use, and 17 (10%) subjects reported decreasing their use. The number of subjects
322
D. C. Des Jarlais et al. TABLE 3 Comparison of Crack Users With Nonusers-1997-I
Sexual and Drug-Related Risk Behaviors Drugs used IV Any IV drug Any speedball Any heroin Any cocaine Non-IV drugs used Any drug Heroin -snorted Cocaine-snorted Other opiates Barbiturates Other sedatives Marijuana PCP Psychedelics Clonidine Elavil Alcohol Mean number of non-IV drugs used Mean time since last injection (mos.) Sexual activity Prostitution All subjects IVDU femalesb Mean no. IVDU partners Any sharing of syringes
Crack Users (n = 50)
989 Follow-Up Sample
Nonusers (n = 178)
p valuea
80% 44% 30% 68%
51% 18% 16% 44%
0.000 0.000 0.030 0.003
90% 20% 38% 26% 8% 14% 64% 8% 6% 18% 40% 58% 2.3 18.8
75% 8% 24% 4% 1% 5% 38% 0% 1% 7% 15% 36% 1.2 45.5
0.021 0.021 0.042 0.000 0.022 0.025 0.001 0.002 0.034 0.024 0.000 0.005 0.002 0.000
16% 55% 1.04 41%
4% 10% 0.48 26%
0.006 0.002 0.006 0.049
Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test
t test t test
Fisher’s Exact Test
t test
aAll significance tests are chi-square unless noted otherwise. bn = 11 crack users; n = 30 nonusers.
who began using during this follow-up period (19) was only slightly higher than the number of subjects who reported ceasing use of crack (12). These 12 who did not use crack during the follow-up period represent 39% of the 31 subjects using crack during the first period and re-interviewed in 1988-89. The factors associated with current crack use in 1987-88 provide at most limited inferences about potential causal mechanisms through which a methadone patient might initiate and continue crack use. In order to find predictors of persistent crack use, we examined the relationships of the intake data collected in 198486 with persistent crack use during 1987-89. Persistent crack use was operationally defined as reported use of crack at both the 1987-88 and 1988-89 interviewsthere were 18 subjects (8%) who met this definition. The variables examined as potential predictors included demographics, the number of noninjected drugs used, specific noninjected drugs used, specific individual drugs injected, sexual behavior, AIDS risk behaviors, HIV status, and a 3-item depression scale that was added to the questionnaire for subjects entering the study in 1986. The depression scale was associated with persistent crack use from 1987-88 and 1988-89. Analysis of the separate items in the scale showed that the question on
“feeling depressed in the previous year” was not associated with persistent crack use, but the items “having thought about suicide in the previous year” and “having attempted suicide in the previous year” were both associated with persistent crack use. Thus, it was only more severe depression, with suicidal ideation or attempts, that was associated with persistent crack use in this sample. Results of two stepwise multivariate logistic regressions are presented in Table 7; the first for subjects who entered the study in either 1984 or 1986 and using only the variables that were on both questionnaires; and the second only for subjects who entered the study in 1986. In this second analysis, all behavioral intake variables (including the depression scale) were utilized. The number of noninjected illicit drugs used at intake was a statistically significant predictor of persistent crack use in both analyses, and actually having attempted suicide was a significant predictor of persistent crack use for the subjects who entered the study in 1986.
DISCUSSION
Crack cocaine was used by approximately one quarter of the methadone patients in this sample. The use of
Crack and Methadone Maintenance
323 TABLE 4 Predictors of Crack Use-1967-l YES
IV Drugs used Any IV drug Speedball Heroin Cocaine Non-IV drugs used Any drug Heroin -snorted Cocaine -snorted Other opiates Barbiturates Other sedatives Marijuana PCP Psychedelics Clonidine Elavil Alcohol Sexual activity Prostitution All subjects IVDU females Shares needles
988
NO
n
% Use Crack
n
130 54 44 112
30% 41% 34% 30%
174 184 116
10% 16% 19% 14%
0.000 0.000
178 25 61 20 6 15 100 4 4 21 47 93
25% 40% 31% 65% 67% 47% 32% 100% 75% 43% 43% 31%
50 203 167 208 222 213 128 224 224 207 181 135
10% 20% 19% 18% 21% 20% 14% 21 % 21% 20% 17% 16%
0.021 0.021 0.042 0.000 0.022 0.025 0.001 0.002 0.034 0.024 0.000 0.005
15 9 66
53% 67% 30%
210 32 158
20% 16% 18%
0.006 0.006 0.049
96
% Use Crack
p valuea
0.030 0.003
Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test Fisher’s Exact Test
Fisher’s Exact Test Fisher’s Exact Test
aAll significance tests are chi-square unless noted otherwise
TABLE 5 Use of Crack by Respondent Characteristics - 1987-88 Sampie, N = 228 -Results of Logistic Regression Procedure
Beta
X2
Odds Ratio
95% Cl
-3.11 0.38 0.43 1.19 1.30
48.58 5.59 4.28 8.37 4.51
1.46 1.54 3.28 3.68
1.07-I .99 1.02-2.31 1.47-7.34 1.11-12.26
Wald
Intercept Number of non-IV drugs used= Number of IVDU sexual partnersb Injecting any drugs since last interview Other non-IV opiate use since last interview
P 1 /MO.
116 7 3 1 1
14 6 1 1 0
l -4lMo. 2 0 1 0 1
2-6/Wk. 2 0 2 1 2
1 +/Day 1 3 0 0 1
324
D.C. Des Jarlais et al. TABLE 7 Prediction of Continuing Crack Use-Results Beta
of Logistic Regression Procedure
Wald x2
Odds Ratio
95%
Cl
P
