Skip to main content

Table 3 Data extraction of included studies (N = 17)

From: Defining key design elements of registry-based randomised controlled trials: a scoping review

Authors Year Country Study design and aim Population and sample size Registry
Randomisation Intervention
Trial duration
Loss to follow-up
Data linkage
Alexander et al. [35] 2011 USA Cluster randomised controlled trial
To test a strategy of specific and targeted performance feedback vs. standard feedback for its ability to better facilitate quality improvement
Hospitals in The National Cardiovascular Data Registry (NCDR®) ACTION Registry® – GWTG™
N = 149
Intervention n = 76
Control n = 73
The National Cardiovascular Data Registry (NCDR®) ACTION Registry® – GWTG™ Randomisation was stratified by baseline quality performance score, academic status, and cardiac services (hospitals with cardiac surgery vs. other). Targeted feedback vs. standard feedback.
Trial duration = 18 months
Follow-up = not applicable
Loss to follow-up = not applicable
Performance measures and quality metrics based on the 2008 American College of Cardiology/American Heart Association Performance Measures for myocardial infarction care and ACTION Registry® – GWTGTM metrics
- improvement in the overall composite of all metrics and composite of the 3-site-specific selected metrics
- trends in patient outcomes including in-hospital bleeding and mortality
Barbanti et al. [33] 2015 Italy Investigator-driven, single-centre prospective, open-label, registry-based randomised trial
To investigate the effect of the RenalGuard System on prevention of acute kidney injury (AKI) in patients undergoing transcatheter aortic valve replacement (TAVR)
All consecutive patients with
symptomatic severe aortic stenosis undergoing TAVR
N = 112
Intervention n = 56
Control n = 56
Registry of percutaneous aortic valve replacement (the REPLACE registry) Patients were 1:1 randomly assigned.
Randomisation was obtained with computer-generated codes, which were sealed in sequentially numbered envelopes
RenalGuard vs. standard management.
Trial duration = 11 months
Follow-up = 72 h
Loss to follow-up = 0 patient
The incidence of AKI occurring within the first 72 h after the procedure
- trial-specific information, including renal outcomes of interest not obtained as part of the registry, were collected using additional case report form pages
Daley et al. [26] 2002 USA Randomised controlled trial
To assess the efficacy of letter/telephone recall for immunisation with pneumococcal conjugate vaccine (PCV7) in an economically disadvantaged urban population
All children aged 6 weeks to 22 months, identified from an immunisation registry database
N = 1420
Intervention n = 610
control n = 624
Immunisation registry database Immunisation registry and Microsoft Excel 97 were used to randomly assign subjects to study arms Letter/telephone recall vs. control
Trial duration = 2 months
Follow-up = 2 months
Loss to follow-up = not reported
Receipt of 1 or more doses of PCV7 during the 2-month study period, as recorded in the immunisation registry
Dombkowski et al. [27] 2012 USA A registry-based randomised trial
To assess the feasibility and effectiveness of using a state-wide immunisation information system (IIS) for seasonal influenza vaccine reminders from local health departments (LHDs) targeting children with high-risk conditions
Children aged 24–60 months with high-risk conditions living in 3 county LHD jurisdictions with primarily English-speaking households, identified using the MCIR
N = 3618
Intervention n = 1810
Control n = 1808
Michigan Care Improvement Registry (MCIR Within each LHD jurisdiction,
children were sorted by a random number, with half assigned to the
intervention (reminder) group and half to the control (no reminder)
Reminder notices vs. no reminder notices
Trial duration = 4 months
Follow-up = 4 months
Loss to follow-up = 729 children
Effectiveness was based on the outcome of 1 or more seasonal influenza vaccination doses being entered into MCIR
- feasibility of reminder delivery was evaluated through letters returned by the USPS as undeliverable and through the (NCOA) Link results
Dombkowski et al. [28] 2014 USA A registry-based randomised trial
To assess the relative effectiveness of centralised reminder/recall strategies targeting age-specific vaccination milestones among children in urban areas during June 2008–June 2009
Children aged 7 or 19 months and not up to date for at least 1 dose and children turning age 12 months, regardless of their vaccination status. Eligible children identified via MCIR
N = 10,175
7-month recall n = 2072
12-month reminder n = 3502
19-month recall n = 4601
MCIR Children for reminder/recall were randomised to either the notification (intervention) or no notification
group (control), using an automated group assignment process
Notification vs. no notification
Trial duration = 12 months
Follow-up = 60 days
Loss to follow-up = not reported
MCIR-recorded immunisation activity (administration of Z1 new dose, entry of Z1 historic dose, entry of immunisation waiver) within 60 days following each notification cycle
- the completeness of immunisation activity following the date of notification and the timing of immunisation activity
Erlinge et al. [6] 2017 Sweden Investigator-initiated, multi-centre, randomised, registry-based, open-label clinical trial
To investigate whether the use of bivalirudin would result in a lower rate of the composite of death from any cause, myocardial infarction and major bleeding events than heparin monotherapy (without planned use of glycoprotein IIb/IIIa inhibitors) among patients with either ST-segment-elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) who were undergoing PCI predominantly with the use of radial-artery access and who were receiving treatment with potent P2Y12 inhibitors
Patients admitted to the hospital with a diagnosis of STEMI or NSTEMI and for whom urgent PCI was planned
N = 6006
STEMI n = 3005
NSTEMI n = 3001
Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART registry) Randomisation was performed in a 1:1 ratio in permuted blocks, with the use of a computer-generated list, with stratification according to type of myocardial infarction (STEMI or NSTEMI) and hospital.
Randomisation conducted via the online Swedish
Coronary Angiography and Angioplasty Registry (SCAAR), which is a component of the SWEDEHEART registry
Open-label fashion either intravenously administered bivalirudin (the Medicines Company) vs. intraarterial unfractionated heparin (LEO Pharma)
Trial duration = 26 months
Follow-up = 180 days
Loss to follow-up = 68 patients
A composite of death from any cause, myocardial infarction, or major bleeding during 180 days of follow-up obtained from the Swedish National Population Registry
- answers to trial-specific questions were collected in a separate trial specific
module embedded in the SWEDEHEART online questionnaire
Frobert et al. [16] 2013 Sweden Investigator-initiated, multi-centre, prospective, randomised, registry-based, controlled, open-label clinical trial
To evaluate whether thrombus aspiration reduces mortality
Patients with chest pain suggestive of myocardial ischemia for at least 30 min before hospital admission, if the time from the onset of symptoms to hospital admission was less than 24 h, and if an electrocardiogram
(ECG) showed new ST-segment-elevation or left bundle-branch block
N = 7244
Intervention n = 3621
Control n = 3623
SWEDEHEART registry Patients were randomly assigned, in a 1:1 ratio, and randomisation was performed by means of an online randomisation module within SCAAR Manual thrombus aspiration followed by PCI vs. PCI only
Trial duration = 2 years and 9 months
Follow-up = 30 days
Loss to follow-up = 0 patient
All-cause mortality at 30 days with data on mortality obtained from the national population registry
- 30-day rates of hospitalisation for recurrent myocardial infarction, stent
thrombosis, target-vessel revascularisation, target-
lesion revascularisation and the composite of all-cause mortality or recurrent myocardial infarction obtained from the SWEDEHEART registry and the national discharge registry
- complications of PCI, stroke or neurological complications, heart failure, and length of
stay in the hospital obtained from the registries
Hall et al. [32] 2013 Australia Randomised controlled trial
To assess the effectiveness of an ‘enhanced’ invitation letter in increasing participation in an Australian cancer registry-based study and assess the representativeness of the study sample
Cancer survivors who had haematological cancer, including leukaemias, lymphomas and myelomas, and aged between 18 and 80 years, identified from 1 Australian state-based cancer registry
N = 800
Intervention n = 400 Control n = 400
Australian state-based cancer registry Registry staff used random number allocation to randomise survivors into 1 of 2 groups. Modified invitation letter, incorporating content and design characteristics recommended to improve written communication vs. standard invitation letter
Trial duration = 4 weeks
Follow-up = not applicable
Loss to follow-up = not applicable
Response rate and representativeness of the study sample collected in the cancer registry
Hofmann et al. [36] 2017 Sweden Multi-centre, parallel-group, open-label, registry-based, randomised, controlled trial
To evaluate the effect of oxygen therapy on all-cause mortality at 1 year among patients with suspected myocardial infarction who did not have hypoxemia at baseline
Patients with suspected myocardial infarction and an oxygen saturation of 90% or higher
N = 6629
Intervention n = 3311
Control n = 3318
SWEDEHEART, Swedish National Population Registry and Swedish National Inpatient and Outpatient Registries Unrestricted 1:1 randomisation, using a computer-generated list with the use of an online randomisation module embedded in SWEDEHEART Oxygen (at 6 l per min for 6 to 12 h delivered through an open face mask) vs. ambient air
Trial duration = 2 years and 8 months
Follow-up = 12 months
Loss to follow-up = 403 patients
Rehospitalisation with heart failure and cardiovascular death obtained from SWEDEHEART and the Swedish National Population Registry – including data on mortality and the vital status of all Swedish citizens
Irigoyen et al. [31] 2006 USA Randomised controlled trial
To conduct a randomised controlled trial to assess the relative effectiveness of 2 serial registry reminder protocols at an inner-city practice network
Children aged 6 weeks to 15 months, who had made at least 1 visit to the network, and were due or late for a diphtheria, tetanus and pertussis (DTaP) dose. Eligible children were identified weekly using EzVac
N = 1662
Continuous reminder n = 549
Limited reminder n = 552
Control n = 561
EzVac (hospital immunisation registry) Randomisation was carried out weekly Continuous reminders vs. limited reminders vs. control group
Trial duration = 6 weeks
Follow-up = 6 months
Loss to follow-up = not reported
Received any subsequent immunisation and age-appropriate, up-to-date status at 3 and 6 months tracked with EzVac
- additional immunisations in CIR records for each child not-up-to-date status
Jensen et al. [23] 2016 Denmark A large-scale, registry-based randomised, multi-centre, single-blind, 2-arm, non-inferiority trial
To compare 2 biodegradable polymer drug-eluting stents: the thin-strut cobalt-chromium sirolimus-eluting Orsiro stent and the stainless-steel biolimus-eluting Nobori stent in an all-comer patient population
Patients ≤ 18 years old, chronic stable coronary artery disease or acute coronary syndromes, and at least 1 coronary lesion with > 50% diameter stenosis, requiring treatment with a DES
N = 2525
Intervention n = 1261
Control n = 1264
The Civil Registration System; the National Registry of Patients; The Western Denmark Heart Registry; The National Registry of Causes of Deaths Randomly allocated 1:1 block randomisation by centre.
An independent organisation computer generated the allocation sequence, stratified by sex and presence of diabetes mellitus. Patients were assigned to treatment through a web-based Trial Partner randomisation
The biodegradable polymer sirolimus-eluting stent vs. the biodegradable
polymer biolimus-eluting stent
Trial duration = 15 months
Follow-up = 12 months
Loss to follow-up = 2 patients
Data on mortality, hospital admission, coronary angiography, repeat percutaneous coronary intervention (PCI), and coronary-artery-bypass surgery were obtained from the following national Danish administrative and health care registries: the Civil Registration System; the Western Denmark Heart Registry; and the Danish National Registry of Patients, which maintains records on all hospitalisations in Denmark
Kempe et al. [29] 2005 USA Randomised controlled trial
To assess the maximal influenza immunisation rates that could be achieved for healthy young children in a private practice setting, to evaluate the efficacy of registry-based reminder/recall for influenza vaccination, and to describe methods used by private practices to implement the recommendations
All healthy children aged 6–21 months of age from 5 paediatric practices, identified from an immunisation registry and billing database
N = 5193
Intervention n = 2595 Control n = 2598
Immunisation registry Random allocation of subjects stratified according to practice site 3 reminder/recall letters generated by the immunisation registry vs. usual care
Trial duration = 6 months
Follow-up = 6 months
Loss to follow-up = not reported
Receipt of > 1 influenza immunisation, recorded in either the immunisation registry or billing data
Kristensen et al. [25] 1996 Denmark Retrospective analysis of a prospective, randomised trial based on computerised registries of occurrence of breast cancer and admissions to hospitals
To investigate the occurrence of femoral fractures from a randomised study in postmenopausal women treated with adjuvant tamoxifen and local radiotherapy vs. local radiotherapy alone
Postmenopausal breast cancer women
N = 1716
Intervention n = 868
Control n = 848
Danish National Registry of Patients (DNRP) and Danish Breast Cancer Cooperative Group (DBCG) registry Allocation to treatment was randomised Adjuvant tamoxifen and local radiotherapy vs. local radiotherapy alone.
Trial duration = 5 years and 3 months
Follow-up = 12 years
Loss to follow-up = 0 patient
Occurrence of femoral fractures as recorded in the DNRP registry
Lagerqvist et al. [24] 2014 Sweden Multi-centre, prospective, randomised, controlled, open-label clinical trial
To evaluate clinical outcomes at 1 year after thrombus aspiration
Patients who had planned treatment of acute ST-segment-elevation myocardial infarction (STEMI)
N = 7244
Intervention n = 3621
Control n = 3623
SCAAR, National Population Registries and SWEDEHEART Patients were randomly assigned, in a 1:1 ratio.
Randomisation was performed by means of an online randomisation module within the SCAAR database
Routine thrombus aspiration before PCI vs. PCI alone
Trial duration = 2 years and 9 months
Follow-up = 12 months
Loss to follow-up = 0 patient
Death from any cause, rehospitalisation for myocardial infarction, stent thrombosis, target-vessel revascularisation and target-lesion revascularisation, collected from the registry
- events of a post-hoc-defined composite of death from any cause, rehospitalisation for myocardial infarction, or stent thrombosis
LeBaron et al. [30] 2004 USA Randomised controlled trial
To test whether large-scale reminder recall could meaningfully raise low inner-city immunisation rates and to compare the impact and costs of different forms of reminder recall: in-person telephone calls, mailings and home visits vs. computer-generated telephone calls and mailings
Children aged 24–60 months with high-risk conditions living in 3 county LHD jurisdictions with primarily English-speaking households, identified in an immunisation registry as receiving health care in the public sector
N = 3050
Combination n = 764
Outreach n = 760
Autodialer n = 763
Control n = 763
Metro Atlanta Team for Child Health (MATCH) immunisation registry Participants were assigned by computer-generated random numbers to 1 of 4 groups 1 of 4 groups: autodialer only, outreach only, combination (outreach for children not vaccinated after completion of the autodialer protocol), vs. control (no interventions beyond normal clinic procedure, which in certain cases involved non-automated postcard recall systems).
Trial duration = 24 months
Follow-up = 24 months
Loss to follow-up = not reported
Vaccinations from all providers, public and private, received by study children by 24 months of age and present in the MATCH registry
Rao et al. [17] 2014 USA Investigator-initiated, multi-centre trial, prospective, open-label, registry-based, randomised controlled clinical trial
To determine the effect of radial access on outcomes in women undergoing percutaneous coronary intervention (PCI)
Women undergoing cardiac catheterisation or percutaneous coronary intervention (PCI)
N = 1787
Intervention n = 893
Control n = 894
National Cardiovascular Data Registry’s CathPCI Registry Patients were randomised 1:1 ratio.
Randomisation was performed via an online randomisation module incorporated into the registry trial database
Radial access vs. femoral arterial access
Trial duration = 22 months
Follow-up = 72 h and 30 days
Loss to follow-up = 27 patients
The primary efficacy endpoint was bleeding or vascular complications requiring intervention occurring within 72 h of the procedure or by hospital discharge, whichever came first; as identified in the CathPCI Registry
- the primary feasibility endpoint was access site crossover
Van der Veer et al. [34] 2013 The Netherlands Cluster randomised trial
To assess the impact of applying a multifaceted activating performance feedback strategy on intensive care patient outcomes compared with passively receiving benchmark reports
Intensive care units (ICUs) participating in the Dutch National Intensive Care Evaluation (NICE) registry
N = 30 ICUs
Intervention n = 15 ICUs
Control n = 15 ICUs
N = 25,552 admissions
The Dutch National Intensive Care Evaluation (NICE) registry Randomised ICUs (i.e. clusters), because the intervention was targeted at the facility rather than patient level.
ICUs were randomised according to their size and ability to collect data as determined from prior feasibility study. Randomisation of ICUs was conducted by a dedicated software, blinding those enrolling and assigning the ICUs. Participants were not blinded neither were those involved in providing the strategy
Activating performance feedback strategy vs. benchmark reports
Trial duration = 16 months
Follow-up = 14 months
Loss to follow-up = 0 ICUs
ICU length of stay, as recorded in the NICE data