Postdialysis outcomes associated with consistent anemia treatment in predialysis patients with chronic kidney disease

AIMS: Anemia and cardiovascular (CV) events are major complications of chronic kidney disease (CKD) during dialysis. We conducted a retrospective observational study in CKD patients with anemia to evaluate the association between predialysis use of erythropoiesis-stimulating agents (ESAs) and postdialysis CV outcomes. METHODS: The study analyzed claims data on incident hemodialysis patients aged > or = 18 years (identified between January 2000 and November 2005). Patients were identified as anemic and ESA-treated prior to dialysis. ESA treatment was categorized into 4 consistency groups (from least to most consistent ESA use). RESULTS: Of 5,848 hemodialysis patients, 52% were identified as anemic prior to onset of dialysis. Predialysis ESA treatment was received by 62% of anemic patients, with only 23% receiving the most consistent treatment. The risk of a CV event was significantly lower for the ESA-treated compared with ESA-untreated patients (relative risk (RR) 0.70, 95% (95% confidence intervals (CI) 0.61 - 0.82)). Compared with ESA-untreated, those who received ESAs had significantly lower risk of acute myocardial infarction (RR 0.65 (95% CI 0.44 - 0.95)) or inpatient mortality (RR 0.52 (95% CI 0.40 - 0.68)). ESA-treated patients in each of the 4 consistency groups had significantly lower risk of CV events compared with ESA-untreated patients, with the greatest benefit seen in patients who received most consistent ESA (RR 0.61 (95% CI 0.48 - 0.76)). CONCLUSIONS: This analysis suggests consistent ESA use to treat anemia of CKD in the predialysis period is associated with improved cardiovascular outcomes in postdialysis patients.     

The effect of different linkers on target cell catabolism and pharmacokinetics/pharmacodynamics of trastuzumab maytansinoid conjugates

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate consisting of the anti-HER2 antibody trastuzumab linked via a nonreducible thioether linker to the maytansinoid antitubulin agent DM1. T-DM1 has shown favorable safety and efficacy in patients with HER2-positive metastatic breast cancer. In previous animal studies, T-DM1 exhibited better pharmacokinetics (PK) and slightly more efficacy than several disulfide-linked versions. The efficacy findings are unique, as other disulfide-linked antibody-drug conjugates (ADC) have shown greater efficacy than thioether-linked designs. To explore this further, the in vitro and in vivo activity, PK, and target cell activation of T-DM1 and the disulfide-linked T-SPP-DM1 were examined. Both ADCs showed high in vitro potency, with T-DM1 displaying greater potency in two of four breast cancer cell lines. In vitro target cell processing of T-DM1 and T-SPP-DM1 produced lysine-N(ε)-MCC-DM1, and lysine-N(ε)-SPP-DM1 and DM1, respectively; in vivo studies confirmed these results. The in vitro processing rates for the two conjugate to their respective catabolites were similar. In vivo, the potencies of the conjugates were similar, and T-SPP-DM1 had a faster plasma clearance than T-DM1. Slower T-DM1 clearance translated to higher overall tumor concentrations (conjugate plus catabolites), but unexpectedly, similar levels of tumor catabolite. These results indicate that, although the ADC linker can have clear impact on the PK and the chemical nature of the catabolites formed, both linkers seem to offer the same payload delivery to the tumor.     

Diagnostic Discography: What is the Clinical Utility?

The diagnosis and treatment of discogenic back pain is challenging. Provocation discography, an invasive spinal procedure, has been suggested as a diagnostic test for internal disc disruption to provide information on disc morphology and reproduction of symptoms. Current applications consist of the evaluation of persistent spinal pain in individuals, including postoperative patients, as well as providing a guide for patient selection for spinal fusion surgery and minimally invasive interventional pain procedures. While the validity of discography has been questioned by multiple scientific studies, technical refinements have addressed many of the initial limitations. An updated review on the safety and utility of discography will be provided, covering key areas of debate including false-positive rates, technical parameters, clinical utility, and risk of discography procedural-related intervertebral disc damage.     

Inhibition of the visual cycle in vivo by 13-cis retinoic acid protects from light damage and provides a mechanism for night blindness in isotretinoin therapy

Isotretinoin (13-cis retinoic acid) is frequently prescribed for severe acne [Peck, G. L., Olsen, T. G., Yoder, F. W., Strauss, J. S., Downing, D. T., Pandya, M., Butkus, D. & Arnaud-Battandier, J. (1979) N. Engl. J. Med. 300, 329-333] but can impair night vision [Fraunfelder, F. T., LaBraico, J. M. & Meyer, S. M. (1985) Am. J. Ophthalmol. 100, 534-537] shortly after the beginning of therapy [Shulman, S. R. (1989) Am. J. Public Health 79, 1565-1568]. As rod photoreceptors are responsible for night vision, we administered isotretinoin to rats to learn whether night blindness resulted from rod cell death or from rod functional impairment. High-dose isotretinoin was given daily for 2 months and produced systemic toxicity, but this caused no histological loss of rod photoreceptors, and rod-driven electroretinogram amplitudes were normal after prolonged dark adaptation. Additional studies showed, however, that even a single dose of isotretinoin slowed the recovery of rod signaling after exposure to an intense bleaching light, and that rhodopsin regeneration was markedly slowed. When only a single dose was given, rod function recovered to normal within several days. Rods and cones both showed slow recovery from bleach after isotretinoin in rats and in mice. HPLC analysis of ocular retinoids after isotretinoin and an intense bleach showed decreased levels of rhodopsin chromophore, 11-cis retinal, and the accumulation of the biosynthetic intermediates, 11-cis and all-trans retinyl esters. Isotretinoin was also found to protect rat photoreceptors from light-induced damage, suggesting that strategies of altering retinoid cycling may have therapeutic implications for some forms of retinal and macular degeneration.     

Risk of bacterial infection associated with allogeneic blood transfusion among patients undergoing hip fracture repair

BACKGROUND: The relationship between allogeneic blood transfusion and bacterial infection remains uncertain. An increased risk of bacterial infection would represent the most important risk of allogeneic transfusion, because viral disease transmission has become so rare. STUDY DESIGN AND METHODS: A retrospective cohort study of 9598 consecutive hip fracture patients at least 60 years old who underwent surgical repair was performed. The primary outcome was serious bacterial infection, defined as bacteremia, pneumonia, deep wound infection, or septic arthritis or osteomyelitis. Secondary outcomes included two individual infections, pneumonia and urinary tract infection (UTI), and the cost of infection. Hospital cost of infection was assessed by linking the study population to Medicare data. RESULTS: Fifty-eight percent of patients received at least one transfusion. Serious bacterial infection occurred in 437 patients (4.6%); 28.8 percent of this group died during the hospital stay. Pneumonia occurred in 361 patients (3.8%) and UTI occurred in 1157 patients (12.1%). The adjusted risk of serious bacterial infection associated with transfusion was 1.35 (95% CI, 1.10-1.66). The adjusted risk for pneumonia was 1.52 (95% CI, 1.21-1.91), and that for UTI was 1.03 (95% CI, 0.91-1.17). A dose-response relationship was present for serious bacterial infection (p = 0.001) and pneumonia (p = 0.001). The cost of hospitalization was $14,000 greater for patients with serious infection than for patients without infection. CONCLUSION: Blood transfusion is associated with a 35-percent greater risk of serious bacterial infection and a 52-percent greater risk of pneumonia. Postoperative infections are costly. The risk of bacterial infection may be the most common life-threatening adverse effect of allogeneic blood transfusion.