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Table 2 Summary of the key characteristics of the PolyIran trial and PASTAL trial

From: Ethical issues in cluster randomized trials conducted in low- and middle-income countries: an analysis of two case studies


PolyIran trial

PASTAL trial


Golestan province, Iran



Parallel-arm, individual-cluster trial

Adaptive, parallel, multiarm, two-stage, individual-cluster trial

Design justification

Avoid contamination

Administrative and logistical reasons

Number of clusters

236 villages

Stage 1: 36 antenatal clinic care days

Stage 2: 35 antenatal clinic care days

Number of participants


Stage 1: 1007

Stage 2: 1236

Method of random allocation

1:1 ratio

1:1:1:1:1:1 ratio in stage 1

Data collection procedures

Data collected as part of Golestan cohort study

Review of health records, interviews

Experimental intervention

Polypill plus nonpharmacological prevention

Two oral HIV self-test kits only, or two oral HIV self-test kits with an offer of $3, $10 or lottery incentive conditional on clinic attendance, or followed by a phone call reminder

Control intervention

Nonpharmacological prevention alone

Invitation letter to the male partner offering HIV testing

Primary outcome

Major cardiovascular events

Proportion of male partners who underwent testing for HIV, regardless of serostatus, and linked to clinic for HIV treatment or prevention within 28 days

REC review

Tehran University of Medical Sciences Research Ethics Committee

London School of Hygiene & Tropical Medicine Ethics Committee and College of Medicine Research Ethics Committee


Local health care workers (Behvarz), local religious leaders

Local district health officer, health clinic in-charge

Consent model

Verbal informed consent with documentation

Written informed consent from women; waiver of consent for male partners

  1. REC research ethics committee