to evaluate titles/abstracts and full-text articles for languages other than those for which the team members were fluent. In instances where multiple surveys were conducted in different countries or in different calendar years and reported within the same article, each survey was accounted for separately. Determining the membership criteria for the CKDAfrica Collaboration required careful consideration. With the aim of combining the IPD curated across the network to enhance the ability to examine multiple health outcomes related to CKD, in addition to the ability to report more accurate estimates on the burden of CKD across Africa, a set of common attributes were defined as prerequisites for membership into the network at inception: 1. Studies of observational research design with a priori hypotheses and defined study objectives, participantlevel information, and primary data collection. 2. Studies reporting, or allowing computation of, the prevalence of CKD. CKD could be defined based on estimated glomerular filtration rate (eGFR) and/or the presence of proteinuria/albuminuria, according to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines.23 In the instance where eGFR is used to define CKD, investigators are required to report on the methods used to determine creatinine levels. 3. Studies with ethical approval from their respective ethics organisations, with deidentified data. 4. Studies with a minimum sample size of 300 participants for adult cohorts, aged 18 years and older. The justification for the selected sample size is that studies with small sample sizes are likely to include only few people with CKD, and consequently contribute little or nothing to the estimates in the meta-analyses, while remaining a major contributor to the heterogeneity across studies. Furthermore, we opted for participants aged above 18 years as the main aim of the consortium is to determine the burden of CKD and preventable risk factors driving the disease in Africa. The aetiology of CKD in children differs significantly from CKD in adults, with CKD in children generally caused by birth defects and hereditary diseases, whereas in adults the main drivers being diabetes and hypertension. 5. Studies with participants of African descent residing in Africa. Our first formal call for participation was organised in 2018 (online supplemental addendum B), where corresponding authors of studies containing datasets that met the inclusion criteria were contacted via email, inviting them to contribute primary data for inclusion into the network. From our experience, obtaining data sets through personal contact took as little as 4months, however, not all contacted authors responded initially. In instances of non-response, we attempted to make contact several times, with at least 6months between calls. Since many collaborators may lack time or organisational resources to support essential data sharing tasks (eg, converting data to prespecified digital formats, drafting data sharing agreement), we found a useful technique to obtain the IPD was to minimise the additional responsibilities on the collaborator, like allowing datasets in any digital format. In addition to the non-responding investigators, we also experienced an unwillingness to participate in the network in a very limited number of cases. The main reason for the unwillingness was due to the studies not being completed at the time of our request. After agreement to participate in the network, a memorandum of understanding (online supplemental addendum C), and in some cases, a material transfer agreement (online supplemental addendum D), was signed by both parties as a declaration of mutual understanding. These documents highlighted the role of the parties, the area of focus, ethical and data sharing information, intellectual property rights, commercialisation and publications. This agreement was followed by the electronic version of the data requested. In our case, we used the expanded version of the WHO STEPwise Approach to non-communicable disease risk factor Surveillance (STEPS) Instrument24 as the basis for the scope of variables required (online supplemental addendum B). In instances where investigators are unwilling or unable to transfer data, owing to legal or other logistical reasons, but are prepared to reanalyse their data according to a standard protocol, the CKD-Africa Collaboration secretariat data centre produce a computer code that can be used to generate the required summary statistics. All deidentified data are held centrally at the SAMRC. To maintain the data integrity, protective measures are employed, which include the data being kept on a virusprotected and access-restricted server at the SAMRC, on July 8, 2022 by guest. Protected by copyright. http://gh.bmj.com/ BMJ Glob Health: first published as 10.1136/bmjgh-2021-006454 on 4 August 2021. Downloaded from 4 George C, et al. BMJ Global Health 2021;6:e006454. doi:10.1136/bmjgh-2021-006454 BMJ Global Health which is backed-up daily. This storing procedure is as per the ‘Ethics in health research: principles, processes and structures’, second edition (2015) requirements for electronic data storage, which is the SAMRC’s Ethics Committee’s terms of reference. The process of searching for collaborators, getting everyone on board, finalising the legal aspects of the arrangement and data