Design and sample size of studies included in analysis
| Study | Design | Representative sampling | Years | Sample size used in analysis* | Sample size of study |
| US NHANES | Repeated cross-sectional, national survey | Y | 2009–2014 | 7323 | 7323 |
| China | National cohort | Y | 2009–2010 | 47 191 | 47 204 |
| India CARRS | Cohort study; population in Delhi and Chennai | Y | 2011 | 10 205 | 12 271 |
| ISN KDDC Moldova | General population invited to two primary healthcare units in Chisinau and Ialoveni | N | 2006–2008 | 1384 | 2105 |
| ISN KDDC Nepal | General population invited to temporary or permanent centres | N | 2006–2011 | 19 959 | 21 809 |
| ISN KDDC Nigeria | General population invited to temporary or permanent centres | N | 2008–2009 | 1911 | 1939 |
*Sample size for all studies represents persons ≥20 years of age and with available data on kidney disease markers; additionally, in NHANES, it represents persons who participated in the fasting laboratory draw.
CARRS, Center for Cardiometabolic Risk Reduction in South Asia; ISN, International Society of Nephrology; KDDC, Kidney Disease Data Center; NHANES, National Health and Nutrition Examination Survey.