Daniel Chu

Factors associated with initiating someone into illicit drug injection

AIMS Most people who inject drugs (PWID) were first initiated into injection by a current PWID. Few studies have examined PWID who assist others into drug injection. Our goal is to describe the prevalence of and risk factors for initiating someone into injection in the last 12 months. METHODS We recruited a cross-sectional sample of PWID (N=605) in California from 2011 to 2013. We examined bivariate and multivariate risk factors for initiating someone into injection with a focus on behaviors that might encourage injection initiation such as injecting in front of non-PWID, describing how to inject to non-PWID, and willingness to initiate someone into drug injection. RESULTS Having initiated someone into injection was reported by 34% of PWID overall and 7% in the last 12 months. Forty-four PWID had assisted 431 people into injection in the past year. Factors independently associated with initiating someone into injection in the last 12 months were self-reported likelihood of initiating someone in the future (Adjusted Odds Ratio [AOR]=7.09; 95% Confidence Interval [CI]=3.40, 14.79), having injected another PWID in past month (AOR=4.05; 95% confidence interval [CI]=1.94, 8.47), having described how to inject to non-injectors (2.61; 95% CI=1.19, 5.71), and non-injection powder cocaine use in past month (AOR=4.97; 95% CI=2.08, 11.84) while controlling for study site. CONCLUSION Active PWID are important in facilitating the process of drug injection uptake. Interventions to reduce initiation should include efforts to change behaviors and intentions among PWID that are associated with injection uptake among others.

Initiation of Heroin and Prescription Opioid Pain Relievers by Birth Cohort

We examined initiation patterns among different birth cohorts of people who used prescription opioids and heroin because of historical differences in drug use availability. We examined data from a community-based study of persons who inject drugs (n = 483) in California and a general population survey from the National Survey on Drug Use and Health (n = 1264) and found that individuals born after 1980 were more likely than were individuals born before 1980 to initiate opioids through nonmedical use of prescription opioids than heroin.

Is cannabis use associated with less opioid use among people who inject drugs

BACKGROUND Clinical, experimental, and ethnographic research suggests that cannabis may be used to help manage pain. Ethnographic research has revealed that some people are using cannabis to temper their illicit opioid use. We seek to learn if there is an association between cannabis use and the frequency of nonmedical opioid use among people who inject drugs (PWID). METHODS PWID were recruited using targeted sampling methods in Los Angeles and San Francisco, California, 2011-2013. We limited analysis to people who used opioids in past 30 days (N=653). OUTCOME VARIABLE number of times used any opioids non-medically in past 30 days. Explanatory variable: any cannabis use past 30 days. STATISTICS multivariable linear regression with a log-transformed outcome variable. RESULTS About half reported cannabis use in the past 30 days. The mean and median number of times using opioids in past 30 days were significantly lower for people who used cannabis than those who did not use cannabis (mean: 58.3 vs. 76.4 times; median: 30 vs 60 times, respectively; p<0.003). In multivariable analysis, people who used cannabis used opioids less often than those who did not use cannabis (Beta: -0.346; 95% confidence interval: -0.575, -0.116; p<0.003). CONCLUSIONS There is a statistical association between recent cannabis use and lower frequency of nonmedical opioid use among PWID. This may suggest that PWID use cannabis to reduce their pain and/or nonmedical use of opioids. However, more research, including prospective longitudinal studies, is needed to determine the validity of these findings.

Factors associated with being asked to initiate someone into injection drug use

AIMS Injection drug use initiation typically involves an established person who injects drugs (PWID) helping the injection-naïve person to inject. Prior to initiation, PWID may be involved in behaviors that elevate injection initiation risk for non-injectors such as describing how to inject and injecting in front of injection-naïve people. In this analysis, we examine whether PWID who engage in either of these behaviors are more likely to be asked to initiate someone into drug injection. METHODS Interviews with PWID (N = 602) were conducted in California between 2011 and 2013. Multivariate analysis was conducted to determine factors associated with being asked to initiate someone. RESULTS The sample was diverse in terms of age, race/ethnicity, and drug use patterns. Seventy-one percent of the sample had ever been asked to initiate someone. Being asked to initiate someone was associated with having injected in front of non-injectors (Adjusted Odds Ratio [AOR] = 1.80, 95% Confidence Interval [CI] = 1.12, 2.91), having described injection to non-injectors (AOR = 3.63; 95% CI = 2.07, 6.36), and doing both (AOR = 9.56; 95% CI = 4.43, 20.65) as compared to doing neither behavior (referent). Being female (AOR = 1.73; 95% CI = 1.10, 2.73) and non-injection prescription drug misuse in the last 30 days (AOR = 1.69; 95% CI = 1.12, 2.53) were also associated with having been asked to initiate someone. CONCLUSION Reducing initiation into injection drug use is an important public health goal. Intervention development to prevent injection initiation should include established PWID and focus on reducing behaviors associated with requests to initiate injection and reinforcing refusal skills and intentions among established PWID.

Syringe disposal among people who inject drugs in Los Angeles: The role of sterile syringe source

BACKGROUND Few recent studies have investigated the prevalence of improperly discarded syringes in community settings by people who inject drugs (PWID). We examined whether syringe source was associated with the act of improper syringe disposal and amount of syringes improperly disposed of among PWID in Los Angeles, California. METHODS A cross-sectional sample of PWID (N=412) was recruited and administered a structured questionnaire between July 2011 and April 2013. Descriptive analyses investigated syringe access and disposal practices among participants. Multivariate logistic regression analysis identified adjusted associations between syringe source (syringe exchange program [SEP] or pharmacy) and improper syringe disposal. RESULTS Most participants were male (69%), homeless (62%) and low-income earners (64%). The majority (87%) of the sample received syringes from a SEP in the past six months, with 26% having received syringes from pharmacies and 36% from unauthorised sources (e.g., friend, drug dealer). Of more than 30,000 used syringes reportedly disposed of by participants during the past 30 days, 17% were disposed of improperly. Two percent of participants disposed of any used syringes at pharmacies, compared to 68% who used SEPs for syringe disposal. Having received sterile syringes from a SEP was independently associated with lower odds of improper syringe disposal; however, purchasing sterile syringes from pharmacies was associated with significantly higher odds of improper syringe disposal. CONCLUSION In a city with both SEPs and pharmacies as syringe source and disposal options for PWID, these findings suggest that while pharmacies are selling syringes, they are not as readily involved in safe syringe disposal. Given limits on SEP availability and the large geographic size of Los Angeles County, augmenting current SEP services and providing other community disposal sites, including pharmacy disposal, processes could reduce improper syringe disposal among PWID in Los Angeles.

Drug use generations and patterns of injection drug use: Birth cohort differences among people who inject drugs in Los Angeles and San Francisco, California

OBJECTIVES A robust literature documents generational trends in drug use. We examined the implications of changing national drug use patterns on drug injection histories of diverse people who inject drugs (PWID). METHODS Drug use histories were collected from 776 active PWID in 2011-13. Using descriptive statistics, we examine drug use initiation by year and birth cohort (BC) differences in drug first injected. A multivariate linear regression model of time to injection initiation ([TTII] (year of first injection minus year of first illicit drug use) was developed to explore BC differences. RESULTS The first drug injected by BC changed in tandem with national drug use trends with heroin declining from 77% for the pre-1960s BC to 58% for the 1960s BC before increasing to 71% for the 1990s BC. Multivariate linear regression modeling found that shorter TTII was associated with the 1980s/1990s BC (-3.50 years; 95% Confidence Interval [CI]=-0.79, -6.21) as compared to the 1970s BC. Longer TTII was associated with being female (1.65 years; 95% CI=0.40, 2.90), African American (1.69 years; 95% CI=0.43, 2.95), any substance use treatment prior to injection (4.22 years; 95% CI=2.65, 5.79), and prior non-injection use of drug that was first injected (3.29 years; 95% CI=2.19, 4.40). CONCLUSION National drug trends appear to influence injection drug use patterns. The prescription opiate drug era is associated with shorter TTII. Culturally competent, demographically and generationally-targeted prevention strategies to combat transitions to drug injection are needed to prevent or shorten upstream increases in risky drug use practices on a national level.

Food insecurity among people who inject drugs in Los Angeles and San Francisco.

OBJECTIVE We estimated the prevalence of food insecurity among people who inject drugs (PWID) in Los Angeles and San Francisco and explored correlates of food insecurity. DESIGN A cross-sectional study that measured 30 d food insecurity using the US Adult Food Security Survey ten-item Module developed by the US Department of Agriculture. Food insecurity was defined as including low and very low food security. SETTING Two cities in the state of California, USA. SUBJECTS Male and female active PWID (n 777). RESULTS Among participants, 58 % reported food insecurity and 41 % reported very low food security. Food-insecure PWID were more likely to report being homeless (prevalence ratio (PR)=1·20; 95 % CI 1·05, 1·37), chest pain in the past 12 months (PR=1·19; CI 1·06, 1·35), acquiring syringes from someone who goes to a syringe exchange programme (PR=1·27; 95 % CI 1·13, 1·43) and feeling at risk for arrest for possession of drug paraphernalia (PR=1·30; 95 % CI 1·15, 1·46). CONCLUSIONS Current food insecurity was common among PWID in these two cities, yet few factors were independently associated with food insecurity. These data suggest that broad strategies to improve food access for this high-risk population are urgently needed.

Differences in time to injection onset by drug in California: Implications for the emerging heroin epidemic

BACKGROUND Heroin use is increasing in the US. Heroin use may predispose users towards injection routes of drug administration as compared to other illicit substances. OBJECTIVE To explore the relationship between heroin use and drug injection, we compared time from first use to first injection (referred to as time to injection onset by drug [TTIOD]) of heroin, methamphetamine/speed, cocaine, and crack cocaine among people who inject drugs (PWID). METHODS Age of first use and first injection by drug was collected from 776 PWID. Survival analyses were used to determine TTIOD and to examine demographic factors associated with TTIOD. Cox regression analysis was used to determine demographic factors associated with drug-specific injection onset. RESULTS The eventual injection onset rate by the drug was 99% for participants who used heroin, 85% for participants who used methamphetamine/speed, 80% for participants who used powder cocaine, and 38% for participants who used crack cocaine. Hazard ratios for injection use within one year of first use by drug were: 1.37 (median survival time [MST] = 0.61 years) for heroin, 0.66 (MST = 1.10 years) for methamphetamine/speed, 0.50 (MST = 2.93 years) for powder cocaine, and 0.12 (MST = 39.59 years) for crack cocaine. Demographic differences in TTIOD were found for each drug. Demographic differences were found for eventual injection by drug for all substances except heroin. CONCLUSION Among PWID, heroin use was associated with a more rapid transition to injection and a higher rate of eventual heroin injection regardless of demographics. More robust, innovative efforts to reduce heroin use and prevent injection initiation are urgently needed.