Kidney Function

Background:: Chronic kidney disease (CKD) is an increasingly common condition, especially in older adults. CKD manifests differently in older versus younger patients, with a risk of death that far outweighs the risk of CKD progressing to the point that dialysis is required. Current CKD guidelines recommend a blood pressure target <130/80 mm Hg for all patients with CKD; however, it is unknown how lower versus higher baseline blood pressures may affect older adults with CKD.Study Design:: Retrospective cohort study.Setting & Participants:: Older patients (aged ≥75 years) with CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) in a community-based health maintenance organization.Predictor:: Baseline systolic blood pressure (SBP) <130, 130-160 (reference group), and >160 mm Hg.Outcomes:: Participants were followed up for 5 years to examine rates of mortality (primary outcome) and cardiovascular disease hospitalizations (secondary outcome).Results:: At baseline, 3,099 participants (38.5%) had SBP <130 mm Hg, 3,772 (46.9%) had SBP of 131-160 mm Hg, and 1,171 (14.6%) had SBP >160 mm Hg. A total of 3,734 (46.4%) died and 2,881 (35.8%) were hospitalized. Adjusted HRs for mortality in the groups with SBP <130 and >160 mm Hg were 1.22 (95% CI, 1.11-1.34) and 1.06 (95% CI, 0.93-1.22), respectively. Adjusted HRs for cardiovascular hospitalization in these groups were 1.10 (95% CI, 0.99-1.23) and 1.26 (95% CI, 1.09-1.45), respectively.Limitations:: Although causality should not be inferred from this retrospective analysis, results from this study can generate hypotheses for future randomized controlled trials to investigate the relationship between blood pressure and outcomes in older patients with CKD.Conclusions:: Our study suggests that lower baseline SBP (≤130 mm Hg) may predict poorer outcomes in terms of both mortality and cardiovascular hospitalizations in older adults with CKD. Conversely, higher baseline SBP (>160 mm Hg) may predict increased risk of cardiovascular hospitalizations, but does not predict mortality. Clinical trials are required to test this hypothesis.

Recognizing that autologous arteriovenous fistula use was associated with improved outcomes in hemodialysis patients, the 1997 Dialysis Outcomes Quality Initiative (DOQI) vascular access practice guidelines from the National Kidney Foundation stressed fistulas as the optimal means of dialysis vascular access. In the United States, this emphasis has continued with the Fistula First Breakthrough Initiative. Much of the data supporting fistulas for dialysis access are derived from longitudinal cohorts, including the Dialysis Outcomes and Practice Patterns Study (DOPPS), dialysis provider databases, and other sources. This article reviews major findings from these data sources, focusing on specific practices and characteristics associated with greater arteriovenous fistula use in dialysis facilities worldwide. Important and often overlooked characteristics that are discussed in detail include specific preferences of dialysis staff regarding access type and the emphasis placed on fistula primacy and the number of fistulas created during surgical training. For example, in the DOPPS, the risk of initial fistula failure was 34% lower when fistulas were placed by surgeons who had created at least 25 fistulas during training (P = 0.002). It is imperative that dialysis clinicians advocate actively for specific dialysis access types on behalf of individual patients. Vascular surgery teaching programs must supervise adequate numbers of fistula procedures for every trainee.

Background:: The ACHIEVE (Optimizing the Treatment of Secondary Hyperparathyroidism: A Comparison of Sensipar and Low Dose Vitamin D vs Escalating Doses of Vitamin D Alone) trial evaluated the efficacy of treatment with cinacalcet plus low-dose activated vitamin D analogues (Cinacalcet-D) compared with vitamin D analogues alone (Flex-D) in attaining KDOQI (Kidney Disease Outcomes Quality Initiative) targets for secondary hyperparathyroidism (SHPT). The economic implications of these treatment regimens have not been explored.Study Design: Economic analysis of SHPT treatment in hemodialysis patients.Setting & Population: This analysis used data from the ACHIEVE trial, in which patients received either Cinacalcet-D or Flex-D.Model, Perspective, & Time Frame: We assessed the relative cost-effectiveness of these regimens in treating SHPT during the 27-week ACHIEVE trial, using a US payer perspective, with medication costs valued in 2006 US dollars.Intervention & Outcomes: Relative cost-effectiveness was assessed using cost-minimization analysis or incremental cost-effectiveness ratios. Effectiveness was measured using biochemical markers.Results: Mean medication costs per patient were $5,852 and $4,332 for the Cinacalcet-D and Flex-D treatment arms, respectively. There were no significant differences for the primary end point (parathyroid hormone level of 150-300 pg/mL and calcium-phosphorus product <55 mg2/dL2) and several of the secondary end points, rendering Cinacalcet-D more costly than Flex-D. For secondary end points, for which Cinacalcet-D was more effective, incremental cost-effectiveness ratios ranged from $2,957 (calcium <9.5 mg/dL) to $22,028 (all KDOQI targets) per patient reaching target. Switching to generic calcitriol would have increased the cost difference between treatment arms ($2,079), whereas switching sevelamer to lanthanum decreased the difference ($1,426).Limitations: Costs and outcomes were derived from a short-term randomized controlled trial and were protocol driven. Clinical outcomes, such as mortality, were not available. Long-term economic conclusions cannot be drawn from these data.Conclusions: Cinacalcet combined with vitamin D analogues was no more effective than vitamin D analogues in achieving the primary ACHIEVE end point and incurred greater costs. This conclusion was not tempered substantially by the cost of vitamin D analogues or oral phosphate binders. Whether the additional costs of cinacalcet are warranted will require longer term models to determine whether changes in serum levels of mineral metabolic markers translate into lower morbidity, mortality, and downstream costs.