Cost-effectiveness of duloxetine for knee OA subjects: the role of pain severity

OBJECTIVE

Establish the impact of pain severity on the cost-effectiveness of generic duloxetine for knee osteoarthritis (OA) in the United States.

DESIGN

We used a validated computer simulation of knee OA to compare usual care (UC) - intra-articular injections, opioids, and total knee replacement (TKR) - to UC preceded by duloxetine in those no longer achieving pain relief from non-steroidal anti-inflammatory drugs (NSAIDs). Outcomes included quality-adjusted life years (QALYs), lifetime medical costs, and incremental cost-effectiveness ratios (ICERs). We considered cohorts with mean ages 57-75 years and Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain 25-55 (0-100, 100-worst). We derived inputs from published data. We discounted costs and benefits 3% annually. We conducted sensitivity analyses of duloxetine efficacy, duration of pain relief, toxicity, and costs.

RESULTS

Among younger subjects with severe pain (WOMAC pain = 55), duloxetine led to an additional 9.6 QALYs per 1,000 subjects (ICER = $88,500/QALY). The likelihood of duloxetine being cost-effective at willingness-to-pay (WTP) thresholds of $50,000/QALY and $100,000/QALY was 40% and 54%. Offering duloxetine to older patients with severe pain led to ICERs >$150,000/QALY. Offering duloxetine to subjects with moderate pain (pain = 25) led to ICERs <$50,000/QALY, regardless of age. Among knee OA subjects with severe pain (pain = 55) who are unwilling or unable to undergo TKR, ICERs were <$50,600/QALY, regardless of age.

CONCLUSIONS

Duloxetine is a cost-effective addition to knee OA UC for subjects with moderate pain or those with severe pain unable or unwilling to undergo TKR. Among younger subjects with severe pain, duloxetine is cost-effective at WTP thresholds >$88,500/QALY.

Long-term clinical and economic outcomes of a short-term physical activity program in knee osteoarthritis patients

OBJECTIVE

Physical activity (PA) in the US knee osteoarthritis (OA) population is low, despite well-established health benefits. PA program implementation is often stymied by sustainability concerns. We sought to establish parameters that would make a short-term (3-year efficacy) PA program a cost-effective component of long-term OA care.

METHOD

Using a validated computer microsimulation (Osteoarthritis Policy Model), we examined the long-term clinical (e.g., comorbidities averted), quality of life (QoL), and economic impacts of a 3-year PA program, based upon the SPARKS (Studying Physical Activity Rewards after Knee Surgery) Trial, for inactive knee OA patients. We determined the cost, efficacy, and impact of PA on QoL and medical costs that would make a PA program a cost-effective addition to OA care.

RESULTS

Among the 14 million with knee OA in the US, >4 million are inactive. Participation of 10% in the modeled PA program could save 200 cases of cardiovascular disease, 400 cases of diabetes, and 6,800 quality-adjusted life-years (QALYs). The program had an incremental cost-effectiveness ratio (ICER) of $16,100/QALY. Tripling PA program cost ($860/year) raised the ICER to $108,300/QALY; varying QoL benefits from PA yielded ICERs of $8,800/QALY-$99,900/QALY; varying background cost savings from PA did not qualitatively impact ICERs. Offering the PA program to any adults with knee OA (not only inactive) yielded $31,000/QALY.

CONCLUSION

A PA program with 3-year efficacy in the knee OA population carried favorable long-term clinical and economic benefits. These results offer justification for policymakers and payers considering a PA intervention incorporated into knee OA care.

Heparin is essential for a single keratinocyte growth factor molecule to bind and form a complex with two molecules of the extracellular domain of its receptor

Keratinocyte growth factor (KGF or FGF-7) is a member of the heparin binding fibroblast growth factor (FGF) family and is a paracrine mediator of proliferation and differentiation of a wide variety of epithelial cells. To examine the stoichiometry of complexes formed between KGF and its receptor, we have utilized a soluble variant of the extracellular region of the KGF receptor containing two tandem immunoglobulin-like loops, loops II and III (sKGFR). Ligand-receptor complexes were examined by size exclusion chromatography, light scattering, N-terminal protein sequencing, and sedimentation velocity. In the presence of low-molecular mass heparin ( approximately 3 kDa), we demonstrate the formation of complexes containing two molecules of sKGFR and one molecule of KGF. In the absence of heparin, we were unable to detect any KGF-sKGFR complexes using the above techniques, and additional studies in which sedimentation equilibrium was used show that the binding is very weak (Kd >/= 70 microM). Furthermore, using heparin fragments of defined size, we demonstrate that a heparin octamer or decamer can promote formation of a 2:1 complex, while a hexamer does not. Utilizing the highly purified proteins and defined conditions described in this study, we find that heparin is obligatory for formation of a KGF-sKGFR complex. Finally, 32D cells, which appear to lack low-affinity FGF binding sites, were transfected with a KGFR-erythropoeitin receptor chimera and were found to require heparin to achieve maximal KGF stimulation. Our data are consistent with the previously described concept that cell- or matrix-associated heparan sulfate proteoglycans (HSPGs) and FGF ligands participate in a concerted mechanism that facilitates FGFR dimerization and signal transduction in vivo.

Barriers and facilitators to the utilization of nursing research

The nurse in clinical practice must demonstrate a scientific base for practice grounded in research findings. The purpose of this study was to explore the nurse's perception of the barriers and facilitators to using research findings in nursing practice. A survey methodology was used, and a sample of 356 practicing registered nurses responded. Data were collected using a scale that rated the barriers and facilitators to research utilization. The greatest barriers were insufficient time on the job to implement new ideas, lack of knowledge of nursing research findings, and inaccessibility of relevant literature. The advanced practice nurse is in a pivotal position to decrease the barriers to research utilization.

Differential sequence dynamics of homopolymeric and alternating AT tracts in a small plasmid DNA

The location of OsO4 bispyridine hyper- and hyporeactivity in a small deletion derivative of plasmid ColE1 (PTC12, 1727 bp) has been determined for approximately 70% of the molecule. Thymine bases in homopolymeric (dA)n.(dT)n tracts (n greater than or equal to 4) were always found to be resistant toward OsO4 modification. DNA supercoiling did not destabilize these tracts. The extent of OsO4 bispyridine reactivity of homopolymeric (dA)n.(dT)n tracts, where n = 3, was found to be dependent on the rate of base unpairing of the sequence immediately 5' and 3' to the tract. Repressed OsO4 reactivity of thymine bases in (dA)3.(dT)3 tracts was observed if immediately both 5' and 3' to the tract were stable DNA sequences composed of GC base pairs and/or a homopolymeric (dA)n.(dT)n tract (n greater than or equal to 4). Homopolymeric tracts of n = 3 not having adjacent sequences with repressed unpairing rates did not show reduced levels of OsO4 bispyridine reactivity. Alternating d(TA)n tracts (n greater than or equal to 2) were found to exhibit hyperreactivity with OsO4. The extent of this hyperreactivity was dependent on the length of the tract and superhelical torsional stress. The distribution and frequency of homopolymeric (dA)n.(dT)n (n greater than or equal to 4) tracts in Escherichia coli promoter sequences were examined, and the possible implications of these tracts on promoter function are discussed.

Regulation by calcium of proliferation and morphology of normal human tracheobronchial epithelial cell cultures

Human tracheobronchial epithelial cells have been serially passaged in serum-free medium. This serum-free model was employed to investigate the effects of different concentrations of Ca2+ (0.1, 1.0 and 2.0 mM) on multiplication and morphology of the cells. The responses were analysed in terms of growth kinetics, histochemical and ultrastructural alterations. Culturing of the cells in high Ca2+ (1.0-2.0 mM) medium stimulated cell multiplication characterized by increased colony forming efficiency, greater number of cells per colony and cell population doublings per day. Additionally, the high Ca2+ concentrations induced proliferation in cultures grown to confluency in low Ca2+ (0.1 mM) medium. Cells propagated in low Ca2+ medium consisted of relatively heterogeneous cell populations, with most cells staining positive with periodic acid-Schiff (PAS) reagent. Ultrastructurally the cells exhibited secretory vesicles and microvilli on their surfaces, small desmosomes and intercellular interdigitation between cells and numerous large secretory vesicles in the cytoplasm. The cells grown in high Ca2+ medium acquired characteristics of a highly proliferative phenotype. The cultures consisted of closely packed, relatively homogeneous cells that did not stain with PAS reagent. Their characteristic features were: absence of surface secretory vesicles, reductions of microvilli and intercellular interdigitations, and increases in size and number of desmosomal junctions. The results show that low Ca2+ in the culture medium inhibits cell multiplication and favors the secretory cell phenotype, while high Ca2+ levels stimulate cell multiplication and inhibit the secretory cell phenotype.

Site-directed chemical modification for probing DNA-protein interactions. Osmium tetroxide modification of the -10 site of the lacUV5 promoter enhances open complex formation

A new experimental approach, site-directed chemical modification, was used to explore relationships between RNA polymerase-promoter interactions and function. For this study, the lacUV5 promoter with an exposed -10 thymine on the non-template strand was constructed. Osmium tetroxide was selected as the thymine modifying reagent. Modification occurred predominantly at the exposed -10 T with 5-fold less reactivity at the -12 T residue. The isolated modified strand was used to reconstitute a lacUV5 promoter with -10 (-12) adducts. OsO4 modification at both the -10 and -12 positions of the lacUV5 promoter significantly enhances Escherichia coli RNA polymerase-promoter open complex formation relative to the unmodified promoter. DNase I cleavage sites at -7, -8, and -10 of the unmodified promoter were rendered insusceptible to scission in the modified promoter. However, no difference can be detected in the RNA polymerase footprints for unmodified versus modified open complexes. The latter are fully capable of productive transcription with comparable amounts of identical run-off transcripts to unmodified open complexes. A 16 degrees C reduction in Tm was found for a 14-base pair oligonucleotide duplex containing a single OsO4-bispyridine adduct. The latter result suggests that open complex formation appears to be enhanced due to promoter unpairing at the -10 (-12) adduct sites.

Immunoassays for carbodiimide modified DNA-detection of unpairing transitions in supercoiled ColE1 DNA

The water soluble reagent N-cyclohexyl-N'-beta-(4-methylmorpholinium) ethyl carbodiimide-p-toluene sulphonate (CMC) can be used to probe for unpaired and mismatched sites in DNA. Polyclonal antibodies for CMC modified DNA were produced in order to develop immunological assays for the localization and quantitation of CMC adducts. Immunoslot blot analysis of modified DNA exhibited antibody binding proportional to the extent of CMC modification with adduct detection in the femtamole range. Unmodified DNA did not cross react under the conditions of the assay. The distribution of CMC reactivity for supercoiled ColE1 DNA modified at 100, 200 and 300 mM NaCl was determined by immunoanalysis of EcoRI-Hae2-NruI restriction fragments Southern transferred to nylon membranes. Reactivity above random expectation occurred in the A2-II fragment which can be accounted for by its high A-T content of 71.3%. Reactivity below random expectation occurred in the C fragment which can be accounted for by its low AT content of 43%. CMC modification for the other restriction fragments appeared random.

Effects of vitamin A on growth and differentiation of human tracheobronchial epithelial cell cultures in serum-free medium

Differentiating epithelial cell cultures from human tracheobronchial epithelium have been propagated in serum-free medium. The major objective of this study was to examine the trophic effects of vitamin A on cell multiplication and morphology of the tracheal cell cultures. The cellular responses were analyzed in terms of growth kinetics, morphological and ultrastructural alterations and secretion of glycoconjugates. Cell cultures in control medium exhibited characteristics of epithelial cells including microvilli on cell surfaces, desmosomes between cells, and numerous secretory vesicles in the cytoplasm. Vitamin A at 10(−6) M and 10(−7) M inhibited cell replication and enhanced the secretion of [3H]glucosamine-labeled glycoconjugates. Further, vitamin A increased the production of plasma membrane vesicles and acquisition by the cells of a highly secretory ultrastructure. This in vitro model of human epithelial cells will be important in the investigation of various aspects of growth and differentiation.

Photoperiod time measurement for activity, torpor, molt and reproduction in mice

Resonance light:dark cycles (LD 6:18, 6:30, 6:42, or 6:54) were used to establish that a circadian rhythm of light sensitivity is involved in the thermoregulatory and reproductive responses to a short day photoperiod in the mouse, Peromyscus leucopus. A fifth group was maintained on the long day photoperiod of LD 16:8. After 19 weeks animals presented with LD 6:18 or 6:42 exhibited short day photoperiod responses: gonadal regression, incidence of spontaneous daily torpor and molt to the winter pelage. In contrast animals responded to LD 6:30 and 6:54 as long day photoperiods: maintenance of gonadal system, no incidence of spontaneous daily torpor, and summer pelage. In a second study a T-experiment was conducted to determine that more than one circadian system may regulate these multiple photoperiodic effects. Mice were exposed to 1 of 8 LD cycles for 15 weeks (1:22.00, 1:22.25, 1:22.50, 1:23.00, 1:23.50, 1:23.75, 9:15, or 16:8), Entrained wheel-running activity occurred under all LD regimes. Mice on LD 1:22.50, 1:23.00, and 1:23.50, however, exhibited activity patterns similar to mice on LD 9:15, and they exhibited gonadal regression. Mice on LD 1:22.00, 1:22.25, and 1:23.75 exhibited activity patterns similar to LD 16:8 animals, and most of these animals remained reproductively competent. There was also a close association between occurrence of reproductive regression and daily torpor. In contrast, molt to the winter pelt occurred under all non-24-hr LD cycles. This dysynchrony in response suggests that at least 2 circadian systems are involved in photoperiodic time measurement in P. leucopus.