Abnormal bone turnover in cystic fibrosis adults.

Cystic fibrosis (CF) patients often have low bone mineral density (BMD) and may suffer from fractures and kyphosis. The pathogenesis of low BMD in CF is multifactorial. To study bone metabolism, we collected fasting serum and urine from 50 clinically stable CF adults (mean age 28 years) and 53 matched controls to measure markers of bone formation and bone resorption. The CF subjects had moderate lung disease (FEV1: 46.1 +/- 18.6% predicted) and malnutrition (BMI: 20.0 +/- 3.3 kg/m2). Only 3 subjects had normal BMD. CF subjects had higher urinary N-telopeptides of type I collagen (81.0 +/- 60.0 vs 49.0 +/- 24.2 nm BCE/mmol creatinine, p = 0.0006) and free deoxypyridinoline (7.3 +/- 5.0 vs 5.3 +/- 1.9 nM/mM, p = 0.004) levels than controls. Serum osteocalcin levels were similar in the two groups, a result confirmed by two immunoassays that recognize different epitopes on osteocalcin. Serum bone-specific alkaline phosphatase levels were elevated in CF patients (32.0 +/- 11.3 vs 21.8 +/- 7.0 U/l, p < 0.0001), but were much more closely associated with serum total alkaline phosphatase levels (r = 0.51, p = 0.001) than with age or gender. Parathyroid hormone levels were elevated (p = 0.007) and 25-hydroxyvitamin D levels were depressed (p = 0.0002) in the CF patients in comparison with controls. These results indicate that adults with CF have increased bone resorption with little change in bone formation. Medications that decrease bone resorption or improve calcium homeostasis may be effective therapies for CF bone disease.

Challenges in comparing risk-adjusted bypass surgery mortality results: results from the Cooperative Cardiovascular Project.

OBJECTIVES: We sought to evaluate the predictive accuracy of four bypass surgery mortality clinical risk models and to examine the extent to which hospitals' risk-adjusted surgical outcomes vary depending on which risk-adjustment method is applied. BACKGROUND: Cardiovascular "report cards" often compare risk-adjusted surgical outcomes; however, it is unclear to what extent the risk-adjustment process itself may affect these metrics. METHODS: As part of the Cooperative Cardiovascular Project's Pilot Revascularization Study, we compared the predictive accuracy of four bypass clinical risk models among 3,654 Medicare patients undergoing surgery at 28 hospitals in Alabama and Iowa. We also compared the agreement in hospital-level risk-adjusted bypass outcome performance ratings depending on which of the four risk models was applied. RESULTS: Although the four risk models had similar discriminatory abilities (C-index, 0.71 to 0.74), certain models tended to overpredict mortality in higher-risk patients. There was high correlation between a hospital's risk-adjusted mortality rates regardless of which of the four models was used (correlation between risk-adjusted rating, 0.93 to 0.97). In contrast, there was limited agreement in which hospitals were identified as "performance outliers" depending on which risk-adjustment model was used and how outlier status was defined. CONCLUSIONS: A hospital's risk-adjusted bypass surgery mortality rating, relative to its peers, was consistent regardless of the risk-adjustment model applied, supporting their use as a means of provider performance feedback. Designation of performance outliers, however, can vary significantly depending on the benchmark and methods used for this determination.

Cost-effectiveness of platelet glycoprotein IIb/IIIa inhibition with eptifibatide in patients with non-ST-elevation acute coronary syndromes.

BACKGROUND: In the PURSUIT trial, eptifibatide significantly reduced the 30-day incidence of death and myocardial infarction relative to placebo in 9461 patients with an acute coronary syndrome (unstable angina or non-Q-wave myocardial infarction). METHODS AND RESULTS: We conducted a 2-part prospective economic substudy of the 3522 US patients enrolled in PURSUIT: (1) an empirical intention-to-treat comparison of medical costs (hospital plus physician) up to 6 months after hospitalization and (2) a lifetime cost-effectiveness analysis. The base-case cost-effectiveness ratio was expressed as the 1996 US dollars required to add 1 life-year with eptifibatide therapy. The 2 treatment arms had equivalent resource consumption and medical costs (exclusive of the cost of the eptifibatide regimen) during the index (enrollment) hospitalization (P=0.78) and up to 6 months afterward (P=0.60). The average wholesale price of the eptifibatide regimen was $1217, but a typical hospital discounted price was $1014. The estimated life expectancy from randomization in the US patients was 15.96 years for eptifibatide and 15.85 years for placebo, an incremental difference of 0.111. The incremental cost-effectiveness ratio for eptifibatide therapy in US PURSUIT patients was $16 491 per year of life saved. This result was robust through a wide range of sensitivity analyses. The cost-utility ratio for eptifibatide (using time trade-off defined utilities) was $19 693 per added quality-adjusted life-year. CONCLUSIONS: Based on the results observed in the US PURSUIT patients, the routine addition of eptifibatide to standard care for non-ST-elevation acute coronary syndrome patients is economically attractive by conventional standards.

Increased rate of fractures and severe kyphosis: sequelae of living into adulthood with cystic fibrosis.

BACKGROUND: Osteoporosis occurs in patients with cystic fibrosis as they age, but its clinical implications are not well defined. OBJECTIVE: To determine the clinical effect of decreased bone mineral density in adults with cystic fibrosis and to assess possible clinical predictors of osteoporosis. DESIGN: Retrospective cohort study. SETTING: Academic cystic fibrosis center. PATIENTS: 70 adults with late-stage cystic fibrosis who were referred for lung transplantation. MEASUREMENTS: Bone mineral density was measured with dual-energy x-ray absorptiometry, patient-reported fracture events were confirmed by radiography, and kyphosis angles were measured by using the Cobb method. RESULTS: Mean bone mineral densities for the spine, femur, and total body were severely depressed in patients with cystic fibrosis, averaging 2 SDs below those of age-matched normal controls (P < 0.001). Patient interviews showed that 54 fractures had occurred over 1410 patient-years, and chest radiographs showed evidence of 14 additional rib and 62 additional vertebral compression fractures. The database (which covered 1410 patient-years) showed that fracture rates were approximately twofold greater in women with cystic fibrosis aged 16 to 34 years (P = 0.015) and men with cystic fibrosis aged 25 to 45 years (P = 0.04) than in the general population. Vertebral compression and rib fractures were 100- and 10-fold more common than expected, respectively (P < 0.001 for both comparisons). The mean kyphosis angle (+/- SD) for this group was markedly abnormal (44 +/- 14 degrees; 62% > or = 40 degrees) and probably contributed to diminished stature (mean height loss, 5.8 cm in men with cystic fibrosis and 5.9 cm in women with cystic fibrosis). Cumulative prednisone dose, body mass index, and age at puberty were the strongest predictors of bone mineral density. CONCLUSIONS: Osteoporosis is universal in adults with late-stage cystic fibrosis, and its complications include increased fracture rates and severe kyphosis.