Relationship of eGFR and Albuminuria to concurrent laboratory abnormalities: An individual participant data meta-analysis in a global consortium

Rationale and Objective: Chronic kidney disease (CKD) is complicated by abnormalities that reflect disruption in filtration, tubular, and endocrine functions of the kidney. Our aim was to explore the relationship of specific laboratory abnormalities and hypertension with the eGFR and albuminuria CKD staging framework. Study Design: Cross-sectional individual participant-level analyses in a global consortium Setting and Study Populations: 17 CKD and 38 general population and high-risk cohorts Selection Criteria for Studies: Cohorts in the CKD Prognosis Consortium with data on eGFR and albuminuria as well as a measure of hemoglobin, bicarbonate, phosphorous, parathyroid hormone, potassium, or calcium, or hypertension. Data Extraction: Data were obtained and analyzed between July 2015 and January 2018. Analytic Approach: We modeled the association of eGFR and albuminuria with hemoglobin, bicarbonate, phosphorous, parathyroid hormone, potassium, and calcium using linear regression; and with hypertension and categorical definitions of each abnormality using logistic regression. Results were pooled using random-effects meta-analyses. Results: The CKD cohorts (n=254,666 participants) were 27% female and 10% black, with mean age 69 years (SD 12). The general population/high-risk cohorts (n=1,758,334) were 50% female and 2% black, with mean age 50 years (SD 16). There was a strong, graded association between lower eGFR and all laboratory abnormalities (odds ratios ranging from 3.27 (95% CI: 2.68-3.97) to 8.91 (95% CI: 7.22-10.99) comparing eGFR 15-29 to eGFR 45-59 ml/min/1.73m2); whereas albuminuria had equivocal or weak associations with abnormalities (odds ratios ranging from 0.77; 95% CI: 0.60-0.99) to 1.92 (95% CI:1.65-2.24) comparing urine albumin to creatinine ratio (ACR) >300 vs ACR and#60;30 mg/g). Limitations: Variation in study era, health care delivery system, typical diet, and laboratory assays. Conclusions: Lower eGFR was strongly associated with higher risk of multiple laboratory abnormalities. Knowledge of risk associations might help guide management in the heterogeneous group of patients with CKD