Simple sample size calculation for cluster-randomized trials

Hayes, Richard; Bennett, Steve

doi:10.1093/ije/28.2.319

Cited by 736 publications

(646 citation statements)

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“…The study sample size was determined using an individual randomized trial sample calculation formula [21], with 80% statistical power, a 5% significance level, and 1.5 design effect. The proportion of women who delivered in a health facility was used to calculate the sample size.…”

Section: Methodsmentioning

confidence: 99%

Effect of a participatory multisectoral maternal and newborn intervention on birth preparedness and knowledge of maternal and newborn danger signs among women in Eastern Uganda: a quasi-experiment study

Kananura

Tetui

Bua

et al. 2017

Global Health Action

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Background: Knowledge of obstetric danger signs and adequate birth preparedness (BP) are critical for improving maternal services utilization. Objectives: This study assessed the effect of a participatory multi-sectoral maternal and newborn intervention on BP and knowledge of obstetric danger signs among women in Eastern Uganda. Methods: The Maternal and Neonatal Implementation for Equitable Systems (MANIFEST) study was implemented in three districts from 2013 to 2015 using a quasi-experimental pre–post comparison design. Data were collected from women who delivered in the last 12 months. Difference-in-differences (DiD) and generalized linear modelling analysis were used to assess the effect of the intervention on BP practices and knowledge of obstetric danger signs. Results: The overall BP practices increased after the intervention (DiD = 5, p < 0.05). The increase was significant in both intervention and comparison areas (7–39% vs. 7–36%, respectively), with a slightly higher increase in the intervention area. Individual savings, group savings, and identification of a transporter increased in both intervention and comparison area (7–69% vs. 10–64%, 0–11% vs. 0–5%, and 9–14% vs. 9–13%, respectively). The intervention significantly increased the knowledge of at least three obstetric danger signs (DiD = 31%) and knowledge of at least two newborn danger signs (DiD = 21%). Having knowledge of at least three BP components and attending community dialogue meetings increased the odds of BP practices and obstetric danger signs’ knowledge, respectively. Village health teams’ home visits, intervention area residence, and being in the 25+ age group increased the odds of both BP practices and obstetric danger signs’ knowledge. Conclusions: The intervention resulted in a modest increase in BP practices and knowledge of obstetric danger signs. Multiple strategies targeting women, in particular the adolescent group, are needed to promote behavior change for improved BP and knowledge of obstetric danger signs.

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Section: Methodsmentioning

confidence: 99%

Effect of a participatory multisectoral maternal and newborn intervention on birth preparedness and knowledge of maternal and newborn danger signs among women in Eastern Uganda: a quasi-experiment study

Kananura

Tetui

Bua

et al. 2017

Global Health Action

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“…Considering slide-positive parasite prevalence as a proportion and haemoglobin as a concentration, 35 clusters with 110 children each would have 80% power to detect a 30% reduction in parasitaemia and a 5 g/L increase in haemoglobin at the 5% level of significance if half the child cohort was sampled. Demonstrating a 60% reduction in house entering mosquitoes (A gambiae) associated with IRS-LLIN, with 90% power and at the 5% level of significance, required six houses in each cluster and 16 clusters in each arm of the trial over two years 35 .…”

Section: Sample Size Rationalementioning

confidence: 99%

Efficacy of indoor residual spraying with dichlorodiphenyltrichloroethane against malaria in Gambian communities with high usage of long-lasting insecticidal mosquito nets: a cluster-randomised controlled trial

Pinder

Jawara

Jarju³

et al. 2015

The Lancet

121

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(2015) 'E cacy of indoor residual spraying with dichlorodiphenyltrichloroethane against malaria in Gambian communities with high usage of long-lasting insecticidal mosquito nets : a cluster-randomised controlled trial.', The lancet., 385 (9976). pp. 1436-1446. Further information on publisher's website:http://dx.doi.org/10.1016/S0140-6736(14)61007-2 Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in The Lancet. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be re ected in this document. Changes may have been made to this work since it was submitted for publication. A de nitive version was subsequently published in The Lancet, 385, 9976, 11 17 April 2015, 10.101661007-2.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

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“…This leads to a design effect of 1.38, and we thus have to randomize at least 13 clusters in each arm. 17 The sample size requirement has been satisfied up to now since each arm involves 13 clusters of an average of 2,744 women…”

Section: Sample Sizementioning

confidence: 99%

A cluster randomized controlled trial of visual, cytology and human papillomavirus screening for cancer of the cervix in rural India

Sankaranarayanan

Nene

Dinshaw

et al. 2005

Intl Journal of Cancer

175

142

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The impact of screening by visual inspection with acetic acid (VIA), cytology or HPV testing on cervical cancer incidence and mortality is investigated in a cluster randomized controlled trial in India. We report findings after the screening phase, when 52 clusters, with a total of 142,701 women aged 30-59 years in Osmanabad District, India, were randomized into 4 arms for a single round of screening by trained midwives with either VIA, cytology or HPV testing as well as a control group. All laboratory tests were done locally. Test-positive women underwent investigations (colposcopy=biopsy) and treatment in the base hospital. Data on participation, test positivity, positive predictive value and detection rates of cervical neoplasia were analyzed using cluster design methodology. Of the eligible women, 72-74% were screened. Test positivity rates were 14.0% for VIA, 7.0% for cytology and 10.3% for HPV. The detection rate of high-grade lesions was similar in all intervention arms (0.7% for VIA, 1.0% for cytology and 0.9% for HPV testing) (p 5 0.06, Mann-Whitney test). While the detection rate for VIA dropped to 0.5% with declining test positivity during the course of the study, it remained constant for cytology and HPV testing. Over 85% of women with high-grade lesions received treatment. Our results show that a high level of participation and good-quality cytology can be achieved in low-resource settings. VIA is a useful alternative but requires careful monitoring. Detection rates obtained by HPV testing were similar to cytology, despite higher investments. ' 2005 Wiley-Liss, Inc.Key words: visual inspection with acetic acid; cytology; human papillomavirus testing; cervical cancer; screening Cervical cancer is an important public health problem of adult women in many developing countries. 1,2 Cytology screening programs have resulted in a marked decline of this disease in developed countries. 2 However, the considerable financial, technical and logistic inputs necessary for effective cytology programs means that the results obtained in developing countries have been, at best, mediocre. 3,4 Hence, it is important to evaluate the effectiveness of alternative methods of screening, such as VIA and HPV testing, that may be more readily implemented in different settings.VIA is simple and inexpensive and can be provided by midwives, nurses and other HWs. Its accuracy at detecting cervical neoplasia has been extensively studied and found to be satisfactory. [5][6][7] The role of persistent infection with oncogenic types of HPV in the etiology of cervical cancer has encouraged the evaluation of HPV testing as a screening tool. [8][9][10] The ultimate proof of efficacy of a screening test for cervical neoplasia is its ability to prevent invasive cancer when implemented in a program setting. Whether a screening program using VIA or HPV testing will be followed by a reduction in disease burden and the cost-effectiveness of these alternate approaches based on real program-based information remain to be established. These appro...

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Simple sample size calculation for cluster-randomized trials

Abstract: The methods are illustrated using two case studies: an unmatched trial of the impact of impregnated bednets on child mortality in Kenya, and a pair-matched trial of improved sexually-transmitted disease (STD) treatment services for HIV prevention in Tanzania.

Cited by 736 publications

References 23 publications

Effect of a participatory multisectoral maternal and newborn intervention on birth preparedness and knowledge of maternal and newborn danger signs among women in Eastern Uganda: a quasi-experiment study

Effect of a participatory multisectoral maternal and newborn intervention on birth preparedness and knowledge of maternal and newborn danger signs among women in Eastern Uganda: a quasi-experiment study

Efficacy of indoor residual spraying with dichlorodiphenyltrichloroethane against malaria in Gambian communities with high usage of long-lasting insecticidal mosquito nets: a cluster-randomised controlled trial

A cluster randomized controlled trial of visual, cytology and human papillomavirus screening for cancer of the cervix in rural India

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