Using wastewater-based epidemiology to estimate drug consumption—Statistical analyses and data presentation

Aim Analysis of wastewater samples can be used to assess population drug use, but reporting and statistical issues have limited the utility of the approach for epidemiology due to analytical results that are below the limit of quantification or detection. Unobserved or non-quantifiable—censored—data are common and likely to persist as the methodology is applied to more municipalities and a broader array of substances. We demonstrate the use of censored data techniques and account for measurement errors to explore distributions and annual estimates of the daily mean level of drugs excreted per capita. Measurements Daily 24-hour composite wastewater samples for 56 days in 2009 were obtained using a random sample stratified by day of week and season for 19 municipalities in the Northwest region of the U.S. Methods Methamphetamine, benzoylecgonine (cocaine metabolite), 3,4-ethylenedioxymethamphetamine (MDMA), methadone, oxycodone and hydrocodone were identified and quantified in wastewater samples. Four statistical approaches (reporting censoring, maximum likelihood estimation, Kaplan-Meier estimates, or complete data calculations) were used to estimate an annual average, including confidence bounds where appropriate, dependent upon the amount of censoring in the data. Findings The proportion of days within a year with censored data varied greatly by drug across the 19 municipalities, with MDMA varying the most (4% to 94% of observations censored). The different statistical approaches each needed to be used given the levels of censoring of measured drug concentrations. Figures incorporating confidence bounds allow visualization of the data that facilitates appropriate comparisons across municipalities. Conclusions Results from wastewater sampling that are below detection or quantification limits contain important information and can be incorporated to create a more complete and valid estimate of drug excretion

Interpreting Methamphetamine Levels in a High-Use Community

Illicit drug use is a largely hidden phenomenon and population measures are notoriously problematic. Reliable and valid data for local, regional and national public health and other interventions are needed. To address this information we examined temporal trends within and across weeks in methamphetamine (MA) in a single location in order to inform a sampling plan for understanding long-term trends in MA use based on sampling raw influent to waste water treatment plants. The measured concentrations in wastewater are used to estimate the total mass of MA consumed MA rather than the number of doses due to the uncertainty surrounding methamphetamine purity, mass of MA per dose, and the number of doses used per day. Results from a region with high levels of MA use indicate that MA levels do not differ significantly between weekdays and weekends (p=0.1), consistent with a predominately regular, daily use pattern use. The potential contribution of legal sales of d- and l-MA to the mass of MA consumed within the community was estimated to range from 3-8%. Limitations and uncertainties associated with estimating the mass of MA consumption include small contributions of prescription and over-the-counter drugs that are metabolized to MA as well as measurement and sampling variability.Keywords: Temporal patterns, Epidemiology wastewater, Methamphetamine (MA)Keywords: Temporal patterns, Epidemiology wastewater, Methamphetamine (MA

Sewage-based epidemiology requires a truly transdisciplinary approach

If asked whether you had consumed illicit drugs recently, would you admit it? If yes, could you precisely recall types of drug, times and amounts used? If you were the person commissioned with the task of quantifying drug use, what approach would you use given the social stigma attached with such behavior? We measure drug residues in sewage, which represents urine of entire populations, to provide an objective estimate of total drug use in a region. In transdisciplinary projects, sewage-based results provide valuable information at unrivaled spatiotemporal resolution complementing traditional data

Wastewater testing compared with random urinalyses for the surveillance of illicit drug use in prisons

Illicit drug use is known to occur among inmate populations of correctional (prison) facilities. Conventional approaches to monitor illicit drug use in prisons include random urinalyses (RUA). Conventional approaches are expected to be prone to bias because prisoners may be aware of which days of the week RUAs are conducted. Therefore, we wanted to compare wastewater loads for methamphetamine and cocaine during days with RUA testing and without.We collected daily 24-h composite samples of wastewater by continuous sampling, computed daily loads for 1 month and compared the frequency of illicit drug detection to the number of positive RUAs. Diurnal data also were collected for 3 days to determine within-day patterns of illicit drugs excretion.Methamphetamine was observed in each sample of prison wastewater with no significant difference in daily mass loads between RUA testing and non-testing days. Cocaine and its major metabolite, benzoylecgonine, were observed only at levels below quantification in prison wastewater. Six RUAs were positive for methamphetamine during the month while none were positive for cocaine out of the 243 RUAs conducted.Wastewater analyses offer data regarding the frequency of illicit drug excretion inside the prison that RUAs alone could not detect

Normalized diurnal and between-day trends in illicit and legal drug loads that account for changes in population

Drug concentrations in composite municipal wastewater samples and census-based estimates of population are used to derive daily loads of illicit substances that are indexed to population. However, such estimates do not provide information on the diurnal trends of substance excretion nor can they account for changes in population. To address these limitations, a series of 1 h composites created by sampling wastewater influent at 6 min intervals was collected over four consecutive days at a single wastewater treatment plant. Creatinine (a urinary indicator), caffeine, methamphetamine, benzoylecgonine (BZE), and cocaine were analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Diurnal trends and between-day trends were substance specific and related to the number of estimated doses and excretory half-life. Normalization to creatinine yielded trends in substances that differed significantly from non-normalized trends by accounting for changes in population within the municipality studied. Increases in normalized substance excretion observed during early morning hours originate from individuals among the resident population of the municipality due to the absence of commuters

Impacts of an Opioid Overdose Prevention Intervention Delivered Subsequent to Acute Care

Background Opioid overdose is a major and increasing cause of injury and death. There is an urgent need for interventions to reduce overdose events among high-risk persons. Methods Adults at elevated risk for opioid overdose involving heroin or pharmaceutical opioids who had been cared for in an emergency department (ED) were randomised to overdose education combined with a brief behavioural intervention and take-home naloxone or usual care. Outcomes included: (1) time to first opioid overdose-related event resulting in medical attention or death using competing risks survival analysis; and (2) ED visit and hospitalisation rates, using negative binomial regression and adjusting for time at risk. Results During the follow-up period, 24% of the 241 participants had at least one overdose event, 85% had one or more ED visits and 55% had at least one hospitalisation, with no significant differences between intervention and comparison groups. The instantaneous risk of an overdose event was not significantly lower for the intervention group (sub-HR: 0.83; 95% CI 0.49 to 1.40). Discussion These null findings may be due in part to the severity of the population in terms of housing insecurity (70% impermanently housed), drug use, unemployment and acute healthcare issues. Given the high overdose and healthcare utilisation rates, more intensive interventions, such as direct referral and provision of housing and opioid agonist treatment medications, may be necessary to have a substantial impact on opioid overdoses for this high-acuity population in acute care settings

Problematic use of prescription-type opioids prior to heroin use among young heroin injectors.

BACKGROUND: Misuse of prescription-type opioids and related adverse health effects are increasing, but little is known about the role of these drugs as a precursor to heroin use. We conducted an exploratory study to determine the proportion of young heroin injectors reporting problematic use of prescription-type opioids prior to using heroin, and to describe the factors associated with prior problematic prescription-type opioid use. METHODS: Between March 2009 and June 2010, we recruited injection drug users (IDUs) for a cross-sectional study of hepatitis C virus infection risk. Participants were aged 18-40 years and had injected illicit drugs within the previous six months. A computerized self-administered survey assessed sociodemographics, drug use history, human immunodeficiency virus (HIV)/hepatitis C virus risk behaviors and perceptions, and medical history. We added questions on prescription-type opioid use to the parent study in March 2010; heroin injectors who subsequently enrolled and reported problematic prescription-type opioid use prior to heroin initiation were compared with other heroin IDUs using univariate and multivariate regression methods. RESULTS: Among 123 heroin IDUs, 49 (39.8%) reported problematic prescription-type opioid use prior to heroin initiation ("prescription-type opioid first injection drug users" [PTO-First IDUs]). PTO-First IDUs had higher odds of injecting with friends (adjusted odds ratio [AOR] 6.01; 95% confidence interval [CI] 1.90-19.07), getting new syringes from a spouse/family member/sex partner (AOR 23.0; 95% CI 2.33-226.0), knowing about the local syringe exchange program (AOR 7.28; 95% CI 1.17-45.05), using powder cocaine (AOR 3.75; 95% CI 1.43-9.86), and perceiving themselves as less likely than other IDUs to get HIV (AOR 4.32; 95% CI 1.26-14.77). They had lower odds of ever being tested for HIV (AOR 0.25; 95% CI 0.08-0.80). CONCLUSION: A high proportion of young heroin IDUs reported problematic prescription-type opioid use prior to initiating heroin use. Our study provides several avenues for future investigation to help further characterize this subset of IDUs and their risks and perceptions related to HIV and other blood-borne pathogens

Problematic use of prescription-type opioids prior to heroin use among young heroin injectors.

BACKGROUND: Misuse of prescription-type opioids and related adverse health effects are increasing, but little is known about the role of these drugs as a precursor to heroin use. We conducted an exploratory study to determine the proportion of young heroin injectors reporting problematic use of prescription-type opioids prior to using heroin, and to describe the factors associated with prior problematic prescription-type opioid use. METHODS: Between March 2009 and June 2010, we recruited injection drug users (IDUs) for a cross-sectional study of hepatitis C virus infection risk. Participants were aged 18-40 years and had injected illicit drugs within the previous six months. A computerized self-administered survey assessed sociodemographics, drug use history, human immunodeficiency virus (HIV)/hepatitis C virus risk behaviors and perceptions, and medical history. We added questions on prescription-type opioid use to the parent study in March 2010; heroin injectors who subsequently enrolled and reported problematic prescription-type opioid use prior to heroin initiation were compared with other heroin IDUs using univariate and multivariate regression methods. RESULTS: Among 123 heroin IDUs, 49 (39.8%) reported problematic prescription-type opioid use prior to heroin initiation ("prescription-type opioid first injection drug users" [PTO-First IDUs]). PTO-First IDUs had higher odds of injecting with friends (adjusted odds ratio [AOR] 6.01; 95% confidence interval [CI] 1.90-19.07), getting new syringes from a spouse/family member/sex partner (AOR 23.0; 95% CI 2.33-226.0), knowing about the local syringe exchange program (AOR 7.28; 95% CI 1.17-45.05), using powder cocaine (AOR 3.75; 95% CI 1.43-9.86), and perceiving themselves as less likely than other IDUs to get HIV (AOR 4.32; 95% CI 1.26-14.77). They had lower odds of ever being tested for HIV (AOR 0.25; 95% CI 0.08-0.80). CONCLUSION: A high proportion of young heroin IDUs reported problematic prescription-type opioid use prior to initiating heroin use. Our study provides several avenues for future investigation to help further characterize this subset of IDUs and their risks and perceptions related to HIV and other blood-borne pathogens

Racial disparities in use of syringe service programs in King County, WA: a comparison of two cross-sectional surveys

Abstract Background Syringe service programs (SSPs) provide tools to people who inject drugs (PWID) to prevent overdose, reduce the risk of HIV and HCV infection, and reduce injection frequency. While effective, previous research suggests that SSPs may not adequately reach some marginalized or particularly vulnerable subpopulations of PWID. Methods To identify disparities in SSP use, data from two cross-sectional surveys conducted in King County, Washington were compared: a survey of SSP clients and a community survey of PWID in King County. It was hypothesized that Black PWID, women, and gender minorities would be underrepresented in the SSP survey relative to the general population of PWID. Results SSP clients identified as White at a significantly higher rate than the community sample of PWID (p = 0.030). Black (p < 0.001), American Indian/Alaska Native (p < 0.001), Latinx/Hispanic (p = 0.009), and Native Hawaiian/ Pacific Islander PWID (p = 0.034) were underrepresented in the SSP client survey. The gender of SSP clients was similar to the distribution seen in the community sample of PWID (p = 0.483). Conclusions Black PWID are underrepresented in Seattle-area SSPs, consistent with studies in other large US cities. Both nationally and in Seattle, overdose deaths have been increasing among Black PWID, and harm reduction strategies are vital to reversing this trend. SSPs should explore and test ways to be more accessible to minority populations