Elsevier

The Lancet

Volume 371, Issue 9631, 28 June–4 July 2008, Pages 2173-2182
The Lancet

Articles
All-cause mortality attributable to chronic kidney disease: a prospective cohort study based on 462 293 adults in Taiwan

https://doi.org/10.1016/S0140-6736(08)60952-6Get rights and content

Summary

Background

Both end-stage renal disease and chronic kidney disease are increasing worldwide; however, the full effect of chronic kidney disease is unknown because mortality risks for all five stages are unavailable. We assessed prevalence and mortality risks for all stages of chronic kidney disease and quantified its attributable mortality in Taiwan.

Methods

The cohort consisted of 462 293 individuals aged older than 20 years who participated in a standard medical screening programme since 1994. As of Dec 31, 2006, we identified 14 436 deaths. Chronic kidney disease was determined by glomerular filtration rate and urinary protein. We estimated national prevalence in Taiwan from the cohort by adjusting age and educational levels. Hazard ratios (HRs) were calculated with Cox proportionate hazards model. We calculated mortality attributable to chronic kidney disease for national population and for low socioeconomic status.

Findings

The national prevalence of chronic kidney disease was 11·93% (95% CI 11·66–12·28), but only 3·54% (3·37–3·68) of participants in the cohort were aware of their disorder. Prevalence was substantially higher in the group with low socioeconomic status than in the high status group (19·87% [19·84–19·91] vs 7·33% [7·31–7·35]). 56 977 (12%) of cohort participants had chronic kidney disease; those with disease had 83% higher mortality for all cause (HR 1·83 [1·73–1·93]) and 100% higher for cardiovascular diseases (2·00 [1·78–2·25]), in a cohort that was observed for 13 years with median follow-up of 7·5 years (IQR 4·0–10·1). 10·3% (95% CI 9·57–11·03) of deaths in the entire population were attributable to chronic kidney disease, but 17·5% (16·27–18·67) of deaths in the low socioeconomic status population. 2350 (39%) deaths occurred before 65 years of age in those with chronic kidney disease. Regular users of Chinese herbal medicines had a 20% (odds ratio 1·20 [1·16–1·24]) increased risk of developing chronic kidney disease.

Interpretation

The high prevalence of chronic kidney disease and its associated all-cause mortality, especially in people with low socioeconomic status, make reduction of this disorder a public-health priority. Promotion of its recognition through the general public knowing their glomerular filtration rate and testing their urine is crucial to reduce premature deaths from all causes and to attenuate this global epidemic.

Funding

None.

Introduction

Chronic kidney disease1, 2, 3, 4 is associated with a wide range of causes of increased mortality.5, 6, 7, 8, 9, 10 However, the public-health effect from mortality due to this disease has not been fully assessed. Such an assessment is urgently needed, especially since chronic kidney disease is associated with a very low public awareness.11, 12, 13 Part of the reason for the inability to provide a full assessment of its effect is because most reports were based on fairly small sample size,6, 8 and data for mortality risks for all five stages of chronic kidney disease were incomplete. The most studied data—the US Renal Data System (USRDS)4—with main focus on end-stage renal disease, included only a small fraction of chronic kidney disease. Most patients with this disorder, however, died from other causes before they reached the dialysis state.3, 14 At earlier stages, chronic kidney disease is believed to be treatable and preventable.14, 15 In most countries, national prevalence of chronic kidney disease is not yet established or has just been assembled,2 which further complicates the effort to assess the full magnitude of the disorder.

Because of the availability of a large cohort of nearly half a million adults, who were medically screened in a standardised process and followed up on their vital status since 1994, we are able to calculate the mortality risks for all five stages of chronic kidney disease and to assess its health effect on the entire population. On the basis of this cohort, we aimed to estimate the national prevalence of chronic kidney disease in Taiwan, assess public awareness, and quantify the attributable mortality for the nation as a whole and particularly for the lower social classes.

Section snippets

Study population

In this prospective study, the cohort consisted of 462 293 participants in a standard medical screening programme run by a private firm (MJ Health Management Institution, Taipei, Taiwan), who were aged 20 years and older with 13 years of follow-up, cumulated from 1994 to 2006. The firm attracted paying participants from all over Taiwan because of its known quality services, operational efficiency, and key facilities that were easily accessible. Membership to the programme was required, with

Results

The mean age of participants in the cohort at the time of recruitment was 41·8 (SD 14·1) years (table 1). The median duration of follow-up was 7·5 years (IQR 4·0–10·1).

More than a quarter of the cohort belonged to the low socioeconomic status group with middle-school education or less (table 1). Mean serum creatinine was 84·6 (SD 25·7) μmol/L, with the median value higher for men than for women (figure 1). One in 12 (7·9%) participants had proteinuria, most of whom had minimal amount (trace or

Discussion

Results from this study have shown that chronic kidney disease contributed to around a tenth of all deaths, which is a similar proportion to that from smoking or obesity.21, 22, 23 The prevalence of chronic kidney disease for Taiwan was similar to that in the USA (13·07%), when rates in Taiwan were age adjusted to the US population (12·67%).2 This study not only confirmed the high prevalence of chronic kidney disease in people from Taiwan, but also quantified a substantial proportion of deaths

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