Study On Risk Factors And Onset Time Of Chronic Kidney Disease Related Metabolic Complications

Objective:Chronic kidney disease (CKD) is a worldwide public health problem with poor prognosis and high cost, which bring a heavy burden to society. CKD-related metabolic complications severely restrict the prognosis and the survival of chronic kidney disease patients. Kidney Disease Outcome Quality Initiative(K/DOQI) recommends evaluating patients with Glomerular Filtration Rate (GFR)<60 ml/min per 1.73 m2 for complications. However, little domestic evidence supports the use of a single GFR threshold for evaluating all metabolic disorders. Our purpose is to discover the metabolic complications related risk factors and to describe the onset time of CKD-related complications at different levels of GFR, which is expected to contribute to early detection, the clinical treatment guide as well as improve prognosis.Methods:The relevant data of adult patients (≥14 yr) hospitalized in Qilu Hospital from August 2008 to September 2009 was retrospectively analyzed, and then we screened in complete compliance with diagnostic criteria for chronic kidney disease from it, while excluding pregnant women and the patients with regular renal replacement therapy. There were 2202 cases left in total to record more useful details, including the patient's sex, age, blood pressure, laboratory parameters (serum creatinine, serum urea nitrogen, fasting food glucose, total cholesterol, triglyceride, low-density lipoprotein, blood uric acid, hemoglobin, hematocrit, serum potassium, serum sodium, serum chloride, serum calcium, serum magnesium, phosphorus, carbon dioxide combining power, total protein, albumin, platelets, blood coagulation 4, urine protein, urine occult blood, etc.), CKD-related history (hypertension, diabetes, cardiovascular disease, connective tissue disease, hepatitis B, gout, etc.), history of smoking, drinking, and medications. eGFR was measured using renal clearance of serum creatinine and estimated through simplified equations of the Modification of Diet in Renal Disease study (MDRD). The associated risk factors of CKD-related metabolic complications (including hyperkalemia, hyperphosphatemia, hypermagnesemia, hypocalcemia, calcium and phosphorus product increased, metabolic acidosis, anemia, hypoalbuminemia, hyperuricemia and prothrombotic state) were analyzed with statistical methods, such as correlation analysis, regression analysis. In order to explore further relationship between the decline of renal function and metabolic complications and to time the onset stages of CKD-related metabolic complications, we used receiver operating characteristic (ROC) curve to analyze the cases with stages 2 through 5 CKD and determined eGFR thresholds associated with the detection of each complication with 90% sensitivity.Results:The prevalences of diverse CKD-related metabolic complications are: hyperkalemia (5.7%), hyperphosphatemia (24.4%), hypermagnesemia (20.5), hypocalcemia (6.0%), calcium and phosphorus product increased (43.9%), metabolic acidosis (32.3%), anemia (47.6%), hypoalbuminemia (44.9%), hyperuricemia (47.6%) and prothrombotic state (78.2%). Factors most strongly associated with metabolic complications while independent of eGFR were as follows:younger age (<65 yr) for hyperphosphatemia and calcium and phosphorus product increased; older age (≥65 yr) for anemia and hyperuricemia, presence of hypertension for hyperkalemia, hyperphosphatemia, hypermagnesemia, hypocalcemia, calcium and phosphorus product increased, metabolic acidosis, anemia, hypoalbuminemia and hyperuricemia; presence of diabetes for anemia; diabetic kidney disease for anemia, hyperkalemia and hypoalbuminemia; glomerulopathy for calcium and phosphorus product increased and hypoalbuminemia; tubulointerstitial disease for hypocalcemia; obstructive nephropathy for metabolic acidosis and anemia. eGFR thresholds for detecting complications with 90% sensitivity were 49.1,50.7,55.4,42.4,63.8,58.5,61.4 and 66.7 ml/min per 1.73 m2 for hyperkalemia, hyperphosphatemia, hypermagnesemia, hypocalcemia, calcium and phosphorus product increased, anemia and hyperuricemia, respectively. In summary, this study is focused on the onset stages of CKD-related complications at different levels of GFR and associated risk factors. We have found that age, hypertension and diabetic kidney disease are the significant risk factors for metabolic complications, anemia, hyperuricemia and calcium and phosphorus metabolism disorders occur at stage 2 which are earlier than metabolic acidosis, hyperphosphatemia, hyperkalemia and hypermagnesemia. Conclusion:CKD-related metabolic complications occur mainly at stage 2 and 3 CKD. Therefore patients at this condition should be screened for metabolic complications, which is aimed at improving the quality of life of patients, reducing the incidence of cardiovascular and cerebrovascular diseases, as well as slowing decline in renal function and improve survival.