CKD incidence varies widely among Singapore’s ethnic groups

Chronic kidney disease (CKD) is common among Asians, particularly in the main ethnic groups in Singapore, with incidence rates ranging between 6 percent and 10 percent, according to a recent study. Such ethnicity-dependent disparities could be partially explained by clinical and socioeconomic factors that may be valuable as targets for intervention.

“Our prospective population-based cohort study in Singapore demonstrated significant ethnic disparities in incident CKD in Asians that were partially explained by clinical, socioeconomic and behavioural factors using traditional logistic regression and machine learning techniques,” the researchers said.

The present prospective cohort included 5,580 general-population participants (aged 40–80 years), most (n=2,234) were of Chinese ethnicity, while 1,474 and 1,872 were Malay and Indian, respectively. Incident CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² among those who were without CKD at baseline.

Through approximately 6 years of follow-up, 10.0 percent of Malays developed CKD, representing the highest incidence rate among ethnic groups. In comparison, only 6.1 percent and 5.8 percent of Chinese and Indian participants were diagnosed with CKD. In turn, the age-standardized annual incidence was significantly higher in Malays as opposed to Chinese and Indian counterparts. [BMJ Open Diabetes Res Care 2021;9:e002364]

Moreover, Malay participants saw more severe incident disease. EGFR <30 mL/min/1.73 m² was detected in 1.2 percent of Malays, as compared with only 0.2 percent in both Indian and Chinese subgroups.

The median percent reduction in eGFR was likewise significantly greater in Malay (33.0 percent) than in Chinese (28.2 percent; p=0.004) and Indian (27.0 percent; p=0.009) participants.

To identify factors that could explain the ethnicity discrepancies in CKD incidence, the researchers constructed logistic regression models, which found that regardless of ethnicity, older age, diabetes, lower eGFR, and higher systolic blood pressure aggravated the risk of CKD.

Meanwhile, hypertension and cardiovascular disease increased CKD risk only in Malays. Hypertension, in particular, had a population attributable risk (PAR) of 54 percent among Malays. In the Indian subgroup, diabetes was found to be an important correlate of CKD risk, with a PAR of 45.2 percent, as opposed to only 35.4 percent in Malays and 33.2 percent in Chinese participants.

Notably, adjusting for clinical, metabolic, socioeconomic, and behavioural factors strongly attenuated the differences in CKD risk across ethnicities. For instance, complete adjustment reduced excess CKD risk in Malays vs Chinese by 64 percent, and vs Indians by 19 percent. Such a finding suggests that these factors may present opportunities for targeted interventions.

“These findings may have important implications in terms of informing policy development and resource allocation in a culturally competent healthcare system to target risk factors that will bring about the greatest reduction in incident CKD,” the researchers said.