Estimation of the Frequency of Intravenous Drug Users in Hamadan City, Iran, Using the Capture-recapture Method

The prevalence of opioid use disorder in Kentucky's counties: A two-year multi-sample capture-recapture analysis

BACKGROUND

Kentucky has one of the highest opioid overdose mortality rates in the United States. Accurate estimates of people with opioid use disorder (OUD) are critical to plan for the scope of interventions required to reduce overdose and opioid misuse. Commonly used household surveys are known to underestimate OUD at the state-level and do not provide county-level estimates.

METHODS

We performed a multi-sample capture-recapture analysis to estimate OUD prevalence in Kentucky in 2018 and 2019. We utilized four statewide datasets that were linked at the individual level: 1) Registry of Vital Statistics, 2) Emergency Medical Services (EMS), 3) Kentucky's Prescription Drug Monitoring Program (PDMP), and 4) Kentucky Medicaid. We included persons aged 18-64 years who resided in Kentucky between 2018 and 2019. We identified individuals with administrative data consistent with OUD in each of the datasets, including a fatal opioid-involved overdose (Vital Statistics), EMS runs for suspected opioid overdose, receipt of buprenorphine for OUD treatment (PDMP), or Medicaid claims for OUD. Observed and estimated counts of OUD cases and prevalence of OUD among the adult population in Kentucky.

RESULTS

The estimated statewide OUD prevalence was 5.5 % and 5.9 % for 2018 and 2019, respectively, ranging from 1.3 % to 17.7 % across Kentucky counties. As expected, counties with the highest OUD rates were Appalachian counties (eastern area) of the state.

CONCLUSIONS

Our analysis reveals a substantially larger proportion of KY residents have OUD than previously estimated. Our approach offers a model for states needing county-level estimates of OUD.

Iranian drug use survey in workplaces: A study protocol

Background: Addiction is a serious concern in workplaces, as it can lead to accidents, absenteeism, and loss of productivity, neglect, delay, arguing, unhappiness, production cuts, and irregular working pattern. This national survey was conducted to assess the prevalence and pattern of drug use among employees of industrial environments in Iran.

Methods: In this cross sectional study, the sample size was determined to be 13489 using multistage cluster sampling method during November 2013 and November 2014. Data were collected by trained interviewers using a structured questionnaire developed by the research team. Urine drug test was done for participants using laboratory rapid kits. A total of 13 286 questionnaires were completed with remarkable responsiveness such that only 1.2% of them were excluded due to defects in urine drug tests, and the rest were analyzed after the review.

Results: The response rate to the questionnaires was 98.4% and 13 128 individuals took the urinary drug test. Many participants who had positive urine test did not express drug use and positive tests were more than self-reported cases. Compared to information about the pattern of drug use, data on the estimated prevalence of drug use was more reliable.

Conclusion: This study presents the protocol of a well-designed national survey, including sampling procedure, appropriate instrument and test, field work, and discussion on the strengths and limitations of the study, and thus its results can be used effectively by policymakers.

Using the capture-recapture method to estimate the human immunodeficiency virus-positive population

OBJECTIVES

The capture-recapture method was applied to estimate the number of human immunodeficiency virus (HIV)-positive individuals not registered with any data sources.

METHODS

This cross-sectional study was conducted in Lorestan Province, in the west of Iran, in 2016. Three incomplete sources of HIV-positive individuals, with partially overlapping data, were used, including: (a) transfusion center, (b) volunteer counseling and testing centers (VCTCs), and (c) prison. The 3-source capture-recapture method, using a log-linear model, was applied for data analysis. The Akaike information criterion and the Bayesian information criterion were used for model selection.

RESULTS

Of the 2,456 HIV-positive patients registered in these 3 data sources, 1,175 (47.8%) were identified in transfusion center, 867 (35.3%) in VCTCs, and 414 (16.8%) in prison. After the exclusion of duplicate entries, 2,281 HIV-positive patients remained. Based on the capture-recapture method, 14,868 (95% confidence interval, 9,923 to 23,427) HIV-positive individuals were not identified in any of the registries. Therefore, the real number of HIV-positive individuals was estimated to be 17,149, and the overall completeness of the 3 registries was estimated to be around 13.3%.

CONCLUSIONS

Based on capture-recapture estimates, a huge number of HIV-positive individuals are not registered with any of the provincial data sources. This is an urgent message for policymakers who plan and provide health care services for HIV-positive patients. Although the capture-recapture method is a useful statistical approach for estimating unknown populations, due to the assumptions and limitations of the method, the population size may be overestimated as it seems possible in our results.

Estimation of Intravenous Drug Users’ Population in Kermanshah City, West of Iran in 2016 using Capture-recapture Method

Background: Drug abuse, particularly intravenous drug use, is one of the most common challenges in human communities so that its negative impact on economic and cultural conditions of society and physical as well as mental health of individuals is evident. We aimed to estimate the IDUs’ population in Kermanshah City, West of Iran using Capture-recapture method.

Study Design: A Cross-sectional study.

Methods: The data in this study were collected from three different sources: Drop in Centers (DICs), Out Reach Teams (ORTs) and Methadone Maintenance Treatment centers (MMTs) in Kermanshah City from Mar 2015 until Mar 2016, and then indirect Capture-recapture was used to estimate the IDUs’ population.

Results: The number of IDUs registered in DICs, ORTs, and MMTs were 694, 731, and 156 cases, respectively. Having determined the commonalities and removing duplicates, the number of drug users registered were 1,375 cases, after analysis of data, the number of drug users not registered in any center was estimated as 2,042 (95% CI: 1708, 2444). By counting 1,375 cases recorded in these sources, the total number of injection drug users in the Kermanshah City was about 3,417 people, (95% CI: (3083, 3819).

Conclusions: The prevalence of IDUs in Kermanshah City is high, which could cause severe economic and social problems in the society. To reduce the negative effects of drug use, awareness and measuring of the drug users population, seem to be necessary overtime.

Estimating the Population Size of Female Sex Worker Population in Tehran, Iran: Application of Direct Capture-Recapture Method

There is no reliable estimate of the size of female sex workers (FSWs). This study aimed to estimate the size of FSWs in south of Tehran, Iran in 2016 using direct capture-recapture method. In the capture phase, the hangouts of FSWs were mapped as their meeting places. FSWs who agreed to participate in the study tagged with a T-shirt. The recapture phase was implemented at the same places tagging FSWs with a blue bracelet. The total estimated size of FSWs was 690 (95% CI 633, 747). About 89.43% of FSWs experienced sexual intercourse prior to age 20. The prevalence of human immunodeficiency virus infection among FSWs was 4.60%. The estimated population size of FSWs was much more than our expectation. This issue must be the focus of special attention for planning prevention strategies. However, alternative estimates require to estimating the number FSWs, reliably.

Estimation of perinatal mortality rate for institutional births in Rajasthan state, India, using capture-recapture technique

OBJECTIVE

The objective of our investigation was to estimate the perinatal mortality rate among institutional births and to compare the sensitivities of different data collection methods.

SETTING

A hospital-based prospective cohort study was undertaken during late-2012 in 21 public sector health facilities of 10 districts of the northern state of Rajasthan, India.

PARTICIPANTS

A total of 6872 births were included in this epidemiological study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Perinatal mortality rate of institutional births was the primary outcome. Sensitivities of 'active' and passive' data collection methods were the secondary outcome measures.

METHODS

All stillbirth data were from routine government records ('passive system'); early neonatal outcome data from government records ('passive') were compared against the method of 'phone-tracking' of outcomes through the community health worker ('active system'). The Lincoln-Petersen formula for capture-recapture method was used to calculate the probable missing number of early neonatal deaths and thereby estimate the institutional perinatal mortality rate.

RESULTS

Ratio of births in district:subdistrict facilities was 55:45. The estimated perinatal mortality rate (95% CI) by capture-recapture method was 35.8 (34 to 37) per 1000 births. The sensitivity of the passive system was 87-89% while the sensitivity of the active system was 91%. Three-fourths of perinatal deaths were documented as stillbirths. However, for these reported intrauterine deaths or stillbirths, clinical classification by typologies (term vs preterm; intrapartum vs antepartum; macerated vs fresh; with or without congenital anomalies) was absent in the recording system.

CONCLUSIONS

Capture-recapture technique can be used to estimate the institutional perinatal mortality rate and also to assess the level of under-reporting by the 'passive' government reporting system. This can subsequently be used for monitoring of trends and studying the impact of health interventions. Accurate clinical categorisation of perinatal deaths is also recommended for improving quality of care.

Estimating the size of the population of persons who inject drugs in the island of Montréal, Canada, using a six-source capture-recapture model

BACKGROUND

To plan and implement services to persons who inject drugs (PWID), knowing their number is essential. For the island of Montréal, Canada, the only estimate, of 11,700 PWID, was obtained in 1996 through a capture-recapture method. Thirteen years later, this study was undertaken to produce a new estimate.

METHODS

PWID were defined as individuals aged 14-65 years, having injected recently and living on the island of Montréal. The study period was 07/01/2009 to 06/30/2010. An estimate was produced using a six-source capture-recapture log-linear regression method. The data sources were two epidemiological studies and four drug dependence treatment centres. Model selection was conducted in two steps, the first focusing on interactions between sources and the second, on age group and gender as covariates and as modulators of interactions.

RESULTS

A total of 1480 PWID were identified in the six capture sources. They corresponded to 1132 different individuals. Based on the best-fitting model, which included age group and sex as covariates and six two-source interactions (some modulated by age), the estimated population was 3910 PWID (95% confidence intervals (CI): 3180-4900) which represents a prevalence of 2.8 (95% CI: 2.3-3.5) PWID per 1000 persons aged 14-65 years.

CONCLUSIONS

The 2009-2010 estimate represents a two-third reduction compared to the one for 1996. The multisource capture-recapture method is useful to produce estimates of the size of the PWID population. It is of particular interest when conducted at regular intervals thus allowing for close monitoring of the injection phenomenon.