Lower serum calcium is independently associated with CKD progression.

Disturbances in calcium metabolism are common in individuals with chronic kidney disease (CKD), but whether they are associated with subsequent kidney function decline is less clear. In a CKD 3-5 cohort of 15,755 adult citizens of Stockholm with creatinine tests taken during 2006-2011 and concurrent calcium testing at cohort entry, we investigated the association between baseline serum calcium and the subsequent change in estimated glomerular filtration rate (eGFR, by CKD-EPI) decline using linear mixed models. Mean (SD) baseline corrected serum calcium was 9.6 (0.5) mg/dL. Mean (95%-confidence interval [CI]) eGFR decline was -0.82 (-0.90; -0.74) mL/min/1.73 m2/year. In advanced CKD stages, higher baseline serum calcium was associated with less rapid kidney function decline. The adjusted change (95%-CI) in eGFR decline associated with each mg/dL increase in baseline serum calcium was -0.10 (-0.28; 0.26), 0.39 (0.07; 0.71), 0.34 (-0.02; 0.70) and 0.68 (0.36; 1.00) mL/min/1.73 m2/year for individuals in CKD stage 3a, 3b, 4, and 5, respectively. In a subgroup of patients using vitamin D supplements, the association between baseline serum calcium and CKD progression was eliminated, especially in CKD stage 3b and 4. To conclude, in individuals with CKD stage 3b to 5, lower baseline corrected serum calcium, rather than higher baseline serum calcium, associated with a more rapid CKD progression. Lower serum corrected calcium seems to be indicative for vitamin D deficiency.

Healthcare costs in chronic kidney disease and renal replacement therapy: a population-based cohort study in Sweden.

OBJECTIVE: To compare healthcare costs in chronic kidney disease (CKD) stage 4 or 5 not on dialysis (estimated glomerular filtration rate <30 mL/min/1.73m2), peritoneal dialysis, haemodialysis and in transplanted patients with matched general population comparators. DESIGN: Population-based cohort study. SETTING: Swedish national healthcare system. PARTICIPANTS: Prevalent adult patients with CKD 4 or 5 (n=1046, mean age 68 years), on peritoneal dialysis (n=101; 64 years), on haemodialysis (n=460; 65 years) and with renal transplants (n=825; 52 years) were identified in Stockholm County clinical quality registers for renal disease on 1 January 2010. 5 general population comparators from the same county were matched to each patient by age, sex and index year. PRIMARY AND SECONDARY OUTCOME MEASURES: Annual healthcare costs in 2009 incurred through inpatient and hospital-based outpatient care and dispensed prescription drugs ascertained from nationwide healthcare registers. Secondary outcomes were annual number of hospital days and outpatient care visits. RESULTS: Patients on haemodialysis had the highest mean annual cost (€87 600), which was 1.49 (95% CI 1.38 to 1.60) times that observed in peritoneal dialysis (€58 600). The mean annual cost was considerably lower in transplanted patients (€15 500) and in the CKD group (€9600). In patients on haemodialysis, outpatient care costs made up more than two-thirds (€62 500) of the total, while costs related to fluids ($29 900) was the largest cost component in patients on peritoneal dialysis (51%). Compared with their matched general population comparators, the mean annual cost (95% CI) in patients on haemodialysis, peritoneal dialysis, transplanted patients and patients with CKD was 45 (39 to 51), 29 (22 to 37), 11 (10 to 13) and 4.0 (3.6 to 4.5) times higher, respectively. CONCLUSIONS: The mean annual costs were ∼50% higher in patients on haemodialysis than in those on peritoneal dialysis. Compared with the general population, costs were substantially elevated in all groups, from 4-fold in patients with CKD to 11, 29 and 45 times higher in transplanted patients and patients on peritoneal dialysis and haemodialysis, respectively.