Risk of hip fracture among dialysis and renal transplant recipients

Context  Renal failure places people at particularly high risk of hip fracture. However, the possible differential impact of dialysis and renal transplantation on this risk is not well understood. Objective  To determine if patients who receive kidney transplants are at greater risk of hip fracture compared with those who continue to undergo dialysis. Design, Setting, and Participants  Cohort study of 101 039 patients with end-stage renal disease placed on the renal transplant waiting list in the United States between January 1, 1990, and December 31, 1999. Main Outcome Measures  Hip fractures, identified from Medicare claims data. Results  Among the patients included in this analysis, 971 hip fractures were observed during the follow-up period of 314 767 person-years. The incidence rate of hip fracture in patients receiving dialysis was 2.9 per 1000 patients per year compared with 3.3 hip fractures per 1000 patients per year in those who had previously received a renal transplant. Initially, the relative risk (RR) of hip fracture associated with transplantation was 1.34-fold greater when compared with dialysis (adjusted RR, 1.34; 95% confidence interval [CI], 1.12-1.61) but then decreased by 1% per month (adjusted RR, 0.99; 95% CI, 0.98-0.99) until the estimated risk became equal for dialysis and transplant recipients approximately 630 days after transplantation (adjusted RR, 1.00; 95% CI, 0.87-1.15). Among transplant recipients, risk of fracture was relatively higher in persons with a prolonged period of dialysis before transplantation. Conclusion  The high risk of hip fracture among dialysis patients is exceeded by that among renal transplant patients during the first 1 to 3 years after transplantation.      

Human skeletal muscle: sodium MR imaging and quantification-potential applications in exercise and disease

PURPOSE: To use sodium 23 magnetic resonance (MR) imaging to quantify noninvasively total sodium in human muscle and to apply the technique in exercise and musculoskeletal disease. MATERIALS AND METHODS: Total [Na] sodium was determined from the ratio of the relaxation-corrected (23)Na signal intensities measured from short echo-time (0.4 msec) (23)Na images to those from an external saline solution reference. The method was validated with the blinded use of saline solutions of varying sodium concentrations. [Na] was measured in the calf muscles in 10 healthy volunteers. (23)Na MR imaging also was performed in two healthy subjects after exercise, two patients with myotonic dystrophy, and two patients with osteoarthritis. RESULTS: (23)Na MR imaging yielded a total [Na] value of 28.4 mmol/kg of wet weight +/- 3.6 (SD) in normal muscle, consistent with prior biopsy data. Spatial resolution was 0.22 mL, with signal-to-noise ratio of 10-15. Mean signal intensity elevations were 16% and 22% after exercise and 47% and 70% in dystrophic muscles compared with those at normal resting levels. In osteoarthritis, mean signal intensity reductions were 36% and 15% compared with those in unaffected knee joints. CONCLUSION: (23)Na MR imaging can be used to quantify total [Na] in human muscle. The technique may facilitate understanding of the role of the sodium-potassium pump and perfusion in normal and diseased muscle.     

Integrating qualitative research into occupational health: a case study among hospital workers

OBJECTIVE: We sought to better use qualitative approaches in occupational health research and integrate them with quantitative methods. METHODS: We systematically reviewed, selected, and adapted qualitative research methods as part of a multisite study of the predictors and outcomes of work-related musculoskeletal disorders among hospital workers in two large urban tertiary hospitals. RESULTS: The methods selected included participant observation; informal, open-ended, and semistructured interviews with individuals or small groups; and archival study. The nature of the work and social life of the hospitals and the foci of the study all favored using more participant observation methods in the case study than initially anticipated. CONCLUSIONS: Exploiting the full methodological spectrum of qualitative methods in occupational health is increasingly relevant. Although labor-intensive, these approaches may increase the yield of established quantitative approaches otherwise used in isolation.     

Kidney function as a predictor of noncardiovascular mortality

Chronic kidney disease is associated with a higher risk for cardiovascular mortality, as well as all-cause mortality. Whether chronic kidney disease is a predictor of noncardiovascular mortality is less clear. To further explore the latter, the association of kidney function with total noncardiovascular mortality and cause-specific mortality was assessed in the Cardiovascular Health Study, a community-based cohort of older individuals. Kidney disease was assessed using cystatin C and estimated GFR in 4637 participants in 1992 to 1993. Participants were followed until June 30, 2001. Deaths were adjudicated as cardiovascular or noncardiovascular disease by committee, and an underlying cause of death was assigned. The associations of kidney function with total noncardiovascular mortality and cause-specific mortality were analyzed by proportional hazards regression. Noncardiovascular mortality rates increased with higher cystatin C quartiles (16.8, 17.1, 21.6, and 50.0 per 1000 person-years). The association of cystatin C with noncardiovascular mortality persisted after adjustment for demographic factors; the presence of diabetes, C-reactive protein, hemoglobin, and prevalent cardiovascular disease; and measures of atherosclerosis (hazard ratio 1.69; 95% confidence interval 1.33 to 2.15, for the fourth quartile versus the first quartile). Results for estimated GFR were similar. The risk for noncardiac deaths attributed to pulmonary disease, infection, cancer, and other causes was similarly associated with cystatin C levels. Kidney function predicts noncardiovascular mortality from multiple causes in the elderly. Further research is needed to understand the mechanisms and evaluate interventions to reduce the high mortality rate in chronic kidney disease.     

Survival following parathyroidectomy among United States dialysis patients

BACKGROUND: Secondary hyperparathyroidism (SHPTH) is highly prevalent among persons with end-stage renal disease (ESRD). SHPTH has been linked to uremic bone disease, vascular calcification, and a higher risk of death. Parathyroidectomy (PTX) can dramatically reduce parathyroid hormone (PTH) and phosphate levels; however, the relationship between PTX and survival is not known. METHODS: We conducted an observational matched cohort study utilizing data from the United States Renal Database System (USRDS) in which 4558 patients undergoing a first PTX while on hemodialysis or peritoneal dialysis were individually matched by age, race, gender, cause of ESRD, dialysis duration, prior transplantation status, and dialysis modality to 4558 control patients who did not undergo PTX. Patients were followed from the date of PTX until they died or were lost to follow-up. RESULTS: The 30-day postoperative mortality rate following PTX was 3.1%. Long-term relative risks of death among patients undergoing PTX were estimated to be 10% to 15% lower than those of matched control patients not undergoing surgery. Survival curves between the 2 groups crossed 587 days following PTX. Median survival was 53.4 months (95% CI: 51.2-56.4) in the PTX group, and 46.8 months (95% CI: 44.7-48.9) in the control group. CONCLUSION: PTX was associated with higher short-term, and lower long-term, mortality rates among U.S. patients receiving chronic dialysis. Measures to attenuate SHPTH may play an important role in reducing mortality among patients with end-stage renal disease.     

Advice that includes food sources of unsaturated fat supports future risk management of gestational diabetes mellitus

Women with gestational diabetes mellitus (GDM) have a greater risk of developing type 2 diabetes mellitus (DM) and heart disease than pregnant women without GDM. Advice given during the GDM pregnancy provides an opportunity to develop protective dietary patterns for the long-term management of this risk. Dietary guidelines for the prevention and management of type 2 DM support the inclusion of unsaturated fats, but food advice needs to target this outcome. The aim of this study was to compare the dietary intakes of women with GDM given general low-fat advice (control group) to women with GDM given the same advice with additional targets for food sources of unsaturated fats (intervention group). After approximately 6 weeks, the intervention group reported more ideal dietary fatty acid intakes than the control group, with polyunsaturated:saturated fat ratios of 1:1 and 0.4:1, respectively (P<.001), assessed using repeated measures analysis of variance. These results confirm the need to include food sources of unsaturated fats in advice strategies to assure optimal protective eating habits in this at-risk group.     

Analysis of prostate-specific antigen rebound interval in patients with prostate cancer receiving hormonal therapy and external-beam radiation therapy

The goal of this investigation is to characterize the clinical significance of the rebound interval (RI) after neoadjuvant short-course hormonal therapy (HT) and external-beam radiation therapy (RT), during which the prostate-specific antigen (PSA) may rise because of hormone withdrawal prior to full RT efficacy. The charts of 257 consecutive patients with localized prostate cancer who received short-course neoadjuvant HT and RT were reviewed. A piecewise-linear log PSA versus time curve was generated for each patient and averaged over the population to facilitate identification of the RI start and end dates. Existing definitions of biochemical failure--American Society for Therapeutic Radiology and Oncology (ASTRO), Vancouver and Houston--were applied, as were these same definitions modified to exclude failures during the RI. Sensitivity and specificity were analyzed, using no evidence (by digital rectal examination or radiology) of disease failure as the gold standard. The 5-year biochemical survival with different failure definitions were ASTRO versus ASTRO-modified: 81.6% versus 86.7%; Houston versus Houston-modified: 71.4% versus 76.7%; and Vancouver versus Vancouver-modified: 83.5% versus 85.6%. The sensitivity and specificity comparisons were ASTRO versus ASTRO-modified 58.3% versus 33.3%; 91.4% versus 94.3%, Vancouver versus Vancouver-modified: 50% versus 50%; 92.7% versus 95.5%, Houston versus Houston-modified: 100% versus 66.7%; 90.6% versus 92.2%. The RI after HT and RT is likely not merely an artifact of hormone withdrawal but is correlated with ultimate clinical outcome. Excluding RI failures can marginally improve specificity but may possibly have an unacceptable risk of lowering sensitivity. Further work is needed to design and validate definitions of failure, which account for the RI.