Design, data analysis and sampling techniques for clinical research

Suresh, Karthik; Thomas, Sanjeev V; Suresh, Geetha

doi:10.4103/0972-2327.91951

Cited by 72 publications

(49 citation statements)

References 6 publications

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“…Participants were randomly selected from all sentenced prisoners within 6 months of release in non-specialized facilities in Kyrgyzstan using a stratified random sampling scheme (Suresh et al, 2011) previously validated in Eastern Europe and Central Asia (Azbel et al, 2013; Azbel et al, 2015). Inclusion criteria were: 1) ≥18 years; 2) currently serving a sentence in a non-specialized facility; and 3) scheduled release within six months.…”

Section: Methodsmentioning

confidence: 99%

Intersecting epidemics of HIV, HCV, and syphilis among soon-to-be released prisoners in Kyrgyzstan: Implications for prevention and treatment

Azbel

Polonsky

Wegman

et al. 2016

International Journal of Drug Policy

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Background Central Asia is plagued by increasing HIV incidence, low antiretroviral therapy (ART) coverage and increasing AIDS mortality, driven primarily by people who inject drugs (PWID). Reliable data about HIV, other infectious diseases, and substance use disorders in prisoners in this region is lacking and could provide important insights into how to improve HIV prevention and treatment efforts in the region. Methods A randomly sampled, nationwide biobehavioral health survey was conducted in 8 prisons in Kyrgyzstan among all soon-to-be-released prisoners; women were oversampled. Consented participants underwent computer-assisted, standardized behavioral health assessment surveys and testing for HIV, HCV, HBV, and syphilis. Prevalence and means were computed, and generalized linear modeling was conducted, with all analyses using weights to account for disproportionate sampling by strata. Results Among 381 prisoners who underwent consent procedures, 368 (96.6%) were enrolled in the study. Women were significantly older than men (40.6 vs. 36.5; p=0.004). Weighted prevalence (%), with confidence interval (CI), for each infection was high: HCV (49.7%; CI: 44.8-54.6%), syphilis (19.2%; CI: 15.1-23.5%), HIV (10.3%; CI: 6.9-13.8%), and HBV (6.2%; CI: 3.6-8.9%). Among the 31 people with HIV, 46.5% were aware of being HIV-infected. Men, compared to women, were significantly more likely to have injected drugs (38.3% vs.16.0%; p=0.001). Pre-incarceration and within-prison drug injection, primarily of opioids, was 35.4% and 30.8%, respectively. Independent correlates of HIV infection included lifetime drug injection (adjusted odds ratio [AOR]=38.75; p=0.001), mean number of years injecting (AOR=0.93; p=0.018), mean number of days experiencing drug problems (AOR=1.09; p=0.025), increasing duration of imprisonment (AOR=1.08; p=0.02 for each year) and having syphilis (AOR=3.51; p=0.003), while being female (AOR=3.06; p=0.004) and being a recidivist offender (AOR=2.67; p=0.008) were independently correlated with syphilis infection. Conclusion Drug injection, syphilis co-infection, and exposure to increased risk during incarceration are likely to be important contributors to HIV transmission among prisoners in Kyrgyzstan. Compared to the community, HIV is concentrated 34-fold higher in prisoners. A high proportion of undiagnosed syphilis and HIV infections presents a significant gap in the HIV care continuum. Findings highlight the critical importance of evidence-based responses within prison, including enhanced testing for HIV and sexually transmitted infections, to stem the evolving HIV epidemic in the region.

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Section: Methodsmentioning

confidence: 99%

Intersecting epidemics of HIV, HCV, and syphilis among soon-to-be released prisoners in Kyrgyzstan: Implications for prevention and treatment

Azbel

Polonsky

Wegman

et al. 2016

International Journal of Drug Policy

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“…The initial sample included 347 students selected by the stratified random sampling method. Stratified random sampling is a sampling procedure wherein the entire statistical population is divided to various subgroups known as strata based on shared characteristics, then participants are randomly selected to form the final sample proportionally from the various strata (32). Sixteen questionnaires were excluded from the study because of incomplete filling and the exclusion criteria.…”

Section: Methodsmentioning

confidence: 99%

Predicting General Well-Being Based on Resiliency Protective Factors and Demographics in Adolescents: The Mediating Role of Emotional Stability

Hossaini

Boogar

Najafi

2017

Int J School Health

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“…Although favorable, completely random sampling is not always feasible as recruitment is often costly and inefficient. As such, alternate sampling methods are used that are most appropriate to the given situation, including convenience sampling, quota sampling or homogenous sampling [6, 7]. For example, observational studies in emergency departments tend to use convenience sampling where patients presenting during “business hours” are selected as more staff are available to process recruitment data [8].…”

Section: Introductionmentioning

confidence: 99%

A pseudo-random patient sampling method evaluated

Mata¹,

Ahn

Kumarasamy

et al. 2017

Journal of Clinical Epidemiology

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Objective To compare two HIV cohorts to determine whether a pseudo-random sample can represent the entire study population. Study Design and Setting HIV-positive patients receiving care at 8 sites in 7 Asian countries. TAHOD pseudo-randomly selected a patient sample, while TAHOD-LITE included all patients. We compared patient demographics, CD4 count and HIV viral load testing for each cohort. Risk factors associated with CD4 count response, HIV viral load suppression (<400 copies/mL) and survival were determined for each cohort. Results There were 2318 TAHOD patients and 14714 TAHOD-LITE patients. Patient demographics, CD4 count and HIV viral load testing rates were broadly similar between the cohorts. CD4 count response and all-cause mortality were consistent among the cohorts with similar risk factors. HIV viral load response appeared to be superior in TAHOD and many risk factors differed, possibly due to viral load being tested on a subset of patients. Conclusions Our study gives the first empirical evidence that analysis of risk factors for completely ascertained endpoints from our pseudo-randomly selected patient sample may be generalized to our larger, complete population of HIV-positive patients. However, results can significantly vary when analysing smaller or pseudo-random samples, particularly if some patient data are not completely missing at random, such as viral load results.

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Design, data analysis and sampling techniques for clinical research

Cited by 72 publications

References 6 publications

Intersecting epidemics of HIV, HCV, and syphilis among soon-to-be released prisoners in Kyrgyzstan: Implications for prevention and treatment

Intersecting epidemics of HIV, HCV, and syphilis among soon-to-be released prisoners in Kyrgyzstan: Implications for prevention and treatment

Predicting General Well-Being Based on Resiliency Protective Factors and Demographics in Adolescents: The Mediating Role of Emotional Stability

A pseudo-random patient sampling method evaluated

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