Vasily Belozeroff

The burden of adult asthma in the United States: Evidence from the Medical Expenditure Panel Survey

BACKGROUND It is important to have an accurate picture of the sources and extent of medical expenditures and productivity loss to understand the nature and scope of the burden of asthma in the United States (US). OBJECTIVE The current study aims to provide recent nationally representative estimates of direct and productivity-related costs attributable to asthma in adults in the US. METHODS The 2003 and 2005 Medical Expenditure Panel Surveys were used to estimate the effect of asthma on medical expenditures, use, productivity, and chronic comorbidity among adults (≥ 18 years). Productivity-related outcome variables included employment, annual wages, missed work days, days spent sick in bed, and activity limitations. Multivariate regression was conducted, controlling for sociodemographics and comorbidity. RESULTS Of 44,795 adults, 1,935 reported an encounter for asthma [corrected]. Compared with those without, subjects with asthma were significantly less likely to be employed (odds ratio, 0.78), spent 1.4 more days sick in bed annually, and were significantly more likely to have activity limitations or to be unable to work. Adults with asthma incurred an additional

Consistent Control of Mineral and Bone Disorder in Incident Hemodialysis Patients

1,907 (2008 US dollars) annually and experienced higher health care use and comorbidity. The total national medical expenditure attributable to adult asthma was

Use of the Asthma Control Questionnaire to predict future risk of asthma exacerbation

18 billion. Adults with asthma were more likely to be covered by Medicaid (30%) than the general adult population (10%). The largest contributors to medical expenditures for adults with asthma were prescription drugs, followed by inpatient hospitalizations and home health care. CONCLUSIONS In recent national data adult asthma is associated with a significant deleterious effect on direct and indirect costs in the US.

Abnormal Bone and Mineral Metabolism in Kidney Transplant Patients – A Review

BACKGROUND AND OBJECTIVES In 2003, the National Kidney Foundation introduced guidelines for the control of parathyroid hormone, calcium, and phosphorus in hemodialysis patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A cohort study was conducted of 22,937 incident hemodialysis patients who were identified from a large national provider between July 1, 2000, and June 30, 2002, and followed through June 30, 2004. Consistent achievement was determined (1) as the simultaneous control of multiple markers over time and (2) as the time in target for each marker during the first year of dialysis. Mortality risk was assessed with Cox proportional hazards models. RESULTS In the simultaneous control analysis, patients who achieved target for none of the markers had a 51% greater risk for death than those who achieved target for all three markers (reference group). Patients who achieved any target for any single marker had a 35 to 39% higher risk for death, and patients who achieved target for any two of the three markers had a 15 to 21% higher risk for death compared with the reference group. In the time in target analysis, patients with parathyroid hormone in target for 4 quarters had a 25% lower risk for death compared with those who did so for <or=1 quarter (reference group). Patients with calcium in target for 4 quarters had a 14% lower risk, and patients with phosphorus in target for 4 quarters had a 38% lower risk. CONCLUSIONS Consistent control of the markers of bone metabolism and disease within published targets is a strong predictor of survival in hemodialysis patients.

Is there an association between elevated or low serum levels of phosphorus, parathyroid hormone, and calcium and mortality in patients with end stage renal disease? A meta-analysis.

BACKGROUND Direct correlation of assessments of a validated composite measure such as the Asthma Control Questionnaire (ACQ) and risk of exacerbation has not been previously demonstrated in a randomized controlled trial. OBJECTIVE To evaluate the ability of the ACQ score over time to predict risk of a future asthma exacerbation. METHODS This analysis included data from a 12-week placebo-controlled trial (N = 292) of AMG 317, an IL-4 receptor α antagonist, in patients with moderate to severe atopic asthma. At baseline, patients had an ACQ score ≥1.5. Exacerbations were defined as requirement for systemic corticosteroids. A Cox proportional hazards model was used, with ACQ score as the time-dependent covariate. The analysis was repeated for individual components of the ACQ. RESULTS Each 1-point increase in ACQ was associated with a 50% increased risk of exacerbation (hazard ratio, 1.50; 95% CI, 1.03-2.20) for the following 2-week period. Evaluation of individual ACQ components also demonstrated a similar trend, though each to a lesser degree than the full composite ACQ. CONCLUSION Although based on a retrospective analysis, with small number of exacerbations, these findings support the utility of the composite ACQ score measurement to predict risk of future exacerbation in clinical trials and clinical practice. The composite ACQ score measurement was found to be a better predictor of future risk than individual ACQ components.

Cinacalcet lowers serum alkaline phosphatase in maintenance hemodialysis patients.

Background/Aims: Abnormal bone and mineral metabolism is common in patients with kidney failure and often persists after successful kidney transplant. Methods: To better understand the natural history of this disease in transplant patients, we reviewed the literature by searching MEDLINE for English language articles published between January 1990 and October 2006 that contained Medical Subject Headings and key words related to secondary or persistent hyperparathyroidism and kidney transplant. Results: Parathyroid hormone levels decreased significantly during the first 3 months after transplant but typically stabilized at elevated values after 1 year. Calcium tended to increase after transplant and then stabilize at the higher end of the normal range within 2 months. Phosphorus decreased rapidly to within or below normal levels after surgery and hypophosphatemia, if present, resolved within 2 months. Low levels of 1,25(OH)2 vitamin D typically did not reach normal values until almost 18 months after transplant. Conclusion: This review provides evidence demonstrating that abnormal bone and mineral metabolism exists in patients after kidney transplant and suggests the need for treatment of this condition. However, better observational and interventional research is needed before advocating such a treatment guideline.

Estimating Health-State Utility for Economic Models in Clinical Studies: an ISPOR Good Research Practices Task Force Report

BackgroundBiochemical markers of altered mineral metabolism have been associated with increased mortality in end stage renal disease patients. Several studies have demonstrated non-linear (U-shaped or J-shaped) associations between these minerals and mortality, though many researchers have assumed linear relationships in their statistical modeling. This analysis synthesizes the non-linear relationships across studies.MethodsWe updated a prior systematic review through 2010. Studies included adults receiving dialysis and reported categorical data for calcium, phosphorus, and/or parathyroid hormone (PTH) together with all-cause mortality. We performed 2 separate meta-analyses to compare higher-than-referent levels vs referent and lower-than-referent levels vs referent levels.ResultsA literature review showed that when a linear relationship between the minerals and mortality was assumed, the estimated associations were more likely to be smaller or non-significant compared to non-linear models. In the meta-analyses, higher-than-referent levels of phosphorus (4 studies, RR = 1.20, 95% CI = 1.15-1.25), calcium (3 studies, RR = 1.10, 95% CI = 1.05-1.14), and PTH (5 studies, RR = 1.11, 95% CI = 1.07-1.16) were significantly associated with increased mortality. Although no significant associations between relatively low phosphorus or PTH and mortality were observed, a protective effect was observed for lower-than-referent calcium (RR = 0.86, 95% CI = 0.83-0.89).ConclusionsHigher-than-referent levels of PTH, calcium, and phosphorus in dialysis patients were associated with increased mortality risk in a selection of observational studies suitable for meta-analysis of non-linear relationships. Findings were less consistent for lower-than-referent values. Future analyses should incorporate the non-linear relationships between the minerals and mortality to obtain accurate effect estimates.

Cost-effectiveness of early versus late cinacalcet treatment in addition to standard care for secondary renal hyperparathyroidism in the USA.

BACKGROUND AND OBJECTIVES Studies suggest an association between elevated serum alkaline phosphatase (AP) and increased mortality in hemodialysis patients, but the effect of existing therapies on AP is not fully understood. We assessed the effects of cinacalcet on AP in a secondary analysis of controlled trial data. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a post hoc analysis of data from three 26-wk randomized, double-blind, placebo-controlled, phase 3 trials and a 26-wk double-blind, placebo-controlled extension trial that investigated cinacalcet in secondary hyperparathyroidism treatment in dialysis patients. Hemodialysis patients (n = 890) with intact parathyroid hormone >or=300 pg/ml and serum calcium >or=8.4 mg/dl received cinacalcet plus standard therapy or standard therapy alone for up to 52 wk. Total, not bone-specific, AP was assessed (proportion of cinacalcet/control subjects achieving a >or=20% or any AP reduction from baseline; the proportion of subjects with AP >or=120 U/L) at baseline; the end of titration; and study weeks 26, 42, and 52. RESULTS At 52 wk, a greater proportion of cinacalcet-treated patients had either a >or=20% (39 versus 18%) or any (58 versus 36%) AP reduction compared with control subjects, respectively. The likelihood of achieving either a >or=20% or any AP reduction (determined by relative proportion) was 2.33 (95% confidence interval 1.50 to 3.61) and 1.74 (95% confidence interval 1.31 to 2.31), respectively, at week 52. Cinacalcet treatment tended toward a decreased percentage of patients with AP >or=120 U/L (baseline, 42.6%; week 52, 30.6%) compared with control (35.0 to 48.6%, respectively). CONCLUSIONS In this combined analysis of controlled trials of patients who were receiving hemodialysis, cinacalcet lowered total serum AP.

Cost-effectiveness of cinacalcet in secondary hyperparathyroidism in the United States

Cost-utility models are increasingly used in many countries to establish whether the cost of a new intervention can be justified in terms of health benefits. Health-state utility (HSU) estimates (the preference for a given state of health on a cardinal scale where 0 represents dead and 1 represents full health) are typically among the most important and uncertain data inputs in cost-utility models. Clinical trials represent an important opportunity for the collection of health-utility data. However, trials designed primarily to evaluate efficacy and safety often present challenges to the optimal collection of HSU estimates for economic models. Careful planning is needed to determine which of the HSU estimates may be measured in planned trials; to establish the optimal methodology; and to plan any additional studies needed. This report aimed to provide a framework for researchers to plan the collection of health-utility data in clinical studies to provide high-quality HSU estimates for economic modeling. Recommendations are made for early planning of health-utility data collection within a research and development program; design of health-utility data collection during protocol development for a planned clinical trial; design of prospective and cross-sectional observational studies and alternative study types; and statistical analyses and reporting.

Economic Evaluation of Cinacalcet in the United States: The EVOLVE Trial

OBJECTIVES The objective of this research was to estimate lifetime cost-effectiveness of treating patients with cinacalcet early (when parathyroid hormone [PTH] levels are in the range of 300-500 pg/ml) versus delaying treatment with cinacalcet (cinacalcet initiated when PTH levels are > 800 pg/ml) in patients with secondary hyperparathyroidism (SHPT) in the US setting. METHODS A Markov model was developed to simulate the effects of early versus delayed use of cinacalcet (plus standard of care). Four different PTH ranges (< or = 300 pg/ml; 301-500 pg/ml; 501-800 pg/ml; > 800 pg/ml) were used to represent four different health states within the Markov model. Associated with each Markov state (PTH range) were varying risks of major SHPT complications, including cardiovascular disease (CVD), fracture (Fx), and parathyroidectomy (PTx). Baseline cohort characteristics and risks of CVD, Fx, and PTx by PTH category were derived from a large US renal database and published sources. Costs were estimated from the US Renal Data System database and reported in 2006 US Dollars (