1.

Missing data.

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Study timeline.

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Prevalence and diagnostic delay.

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Stratification of diagnostic delay patients per group.

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Odds ratio (OR) and the 95% confidence interval (95% CI) for different variables without smoking (complete analyses).

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Odds ratio (OR) and the 95% confidence interval (95% CI) for different variables with smoking (multiple imputation).

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The prevalence of CKD and time to diagnosis, according to the CKD stage.

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The prevalence of CKD according to the age groups.

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Baseline characteristics.