Predictors of ceasing or reducing statin medication following a large increase in the consumer copayment for medications: a retrospective observational study

OBJECTIVES

Previous Australian research has shown that following the 21% increase in patient copayments for medications on the Pharmaceutical Benefits Scheme (PBS) in 2005, the use of lipid-lowering therapy declined by 5%. This study aimed to determine the demographic and clinical characteristics of individuals who continued, reduced or ceased their use of statin medication in 2005.

STUDY TYPE

Retrospective observational study using routinely collected administrative data.

METHOD

We used pharmaceutical claims, hospital separations and mortality records from 2000 to 2005 for the Western Australian population. The cohort comprised stable users of statin medication in 2004. Based on changes in statin use between 2004 and 2005, we identified individuals who: 1) continued using statins; 2) reduced their use by ≥20%; or 3) ceased therapy for at least the first 6 months in 2005. Multivariate logistic regression models were used to determine whether the demographic and clinical characteristics of the three groups differed.

RESULTS

There were 205 924 statin users identified in Western Australia as of December 2004. After the January 2005 Pharmaceutical Benefits Scheme (PBS) copayment increase, 3.2% of users ceased their regular statin therapy, 12.9% reduced statin use and 83.9% continued statin use. This represented a 2.1% increase in statin users reducing or ceasing therapy compared to 2004. Predictors of cessation and reduction of statin therapy included younger age, greater socio-economic disadvantage, residing in very remote areas, having general beneficiary status, being a new statin user, having no prior history of ischaemic heart disease, having no prior history of a coronary artery revascularisation procedure, taking no other cardiovascular medication or diabetic medication, taking an increased number of medications, and having a lower level of adherence to statin medication in 2004.

CONCLUSION

Compared to 2004, an additional 2.1% of statin users reduced or discontinued medication use in 2005, which may be attributed to an increase in the medication copayment. Individuals with general beneficiary status, and younger and healthier people were at particular risk of cessation or reduction in statin use in 2005.

Excellent translational research in oncology: A journey towards novel and more effective anti-cancer therapies

Comprehensive Cancer Centres (CCCs) serve as critical drivers for improving cancer survival. In Europe, we have developed an Excellence Designation System (EDS) consisting of criteria to assess "excellence" of CCCs in translational research (bench to bedside and back), with the expectation that many European CCCs will aspire to this status.

A role for guanine-nucleotide-binding proteins in mediating T-cell-receptor coupling to inositol phospholipid hydrolysis in a murine T-helper (type II) lymphocyte clone

Perturbation of the T-cell receptor (TCR) complex is followed by the rapid hydrolysis of inositol phospholipids (InsPL) by phospholipase C (PLC), producing diacylglycerol and inositol phosphates, which act as second messengers in signal transduction. The mechanism coupling the TCR to InsPL hydrolysis is not clearly defined, and no information is available on this mechanism in the CD4+ helper subset of T-lymphocytes (Th). We have tested the hypothesis that guanine-nucleotide-binding proteins (G-proteins) may couple the TCR to PLC in a murine Th type II (Th2) cell clone. Cell permeabilization with streptolysin O (SLO) or tetanolysin (TL) was used to allow membrane-impermeable nucleotides access to intracellular sites of action. Exposure of permeabilized Th2 cells to guanosine 5'-[gamma-thio]triphosphate (GTP gamma S), a non-hydrolysable GTP analogue, resulted in a 2.1-2.5-fold increase in inositol phosphate generation. Similarly, perturbation of the TCR with the monoclonal antibody 145.2C11 (directed against the epsilon-chain of the CD3 component of the TCR) resulted in a 3.1-4.2-fold increase in InsPL hydrolysis by permeabilized cells. Both lysins were similarly effective in allowing GTP gamma S induction of InsPL hydrolysis, but TL-permeabilized cells responded better to TCR perturbation than SLO-treated cells. A role for G-proteins in TCR coupling to PLC was further supported by the inhibition of TCR-induced InsPL hydrolysis by guanosine 5'-[beta-thio]diphosphate (GDP beta S), a guanine nucleotide analogue that inhibits G-protein function. ATP was required for TCR-mediated InsPL hydrolysis, and potentiated GTP gamma S-induced hydrolysis. Other nucleotides (i.e. CTP, GDP, GTP, ITP) did not affect the response. These data indicate that G-proteins may contribute to the regulation of PLC activation in Th2 cells, coupling it to the TCR.

Release of norepinephrine from brain vesicular preparations: effects of an adenylate cyclase activator, forskolin, and a phosphodiesterase inhibitor

1. The calcium-dependent K+-evoked release of [3H]norepinephrine from guinea pig cerebral cortical vesicular preparations is inhibited by norepinephrine, clonidine, and epinephrine. Isoproterenol has no effect and phentolamine prevents the inhibition by norepinephrine. The results indicate that an alpha-adrenergic receptor mediates an inhibitory input to the calcium-dependent release process. The inhibition by norepinephrine is prevented by high concentrations (3.0 mM) of calcium ions. 2. A cyclic AMP phosphodiesterase inhibitor, ZK 62771, slightly elevates [3H]cyclic AMP levels in the guinea pig cerebral cortical preparation and potentiates the marked elevation of [3H]cyclic AMP elicited by the adenylate cyclase activator, forskolin. 3. Neither ZK 62771 nor forskolin alone has significant effects on K+-evoked release of [3H]norepinephrine from the cerebral cortical vesicular preparation; however, a combination of ZK 62771 and forskolin inhibits K+-evoked release by as much as 60%. The inhibition is reversed by high concentrations (2.0 mM) of calcium ions. The results suggest that a marked accumulation of cyclic AMP elicited via both activation of adenylate cyclase and inhibition of phosphodiesterase can be inhibitory to neurotransmitter release from central synaptic terminals.

Activation of adenylate cyclase by the diterpene forskolin does not require the guanine nucleotide regulatory protein

Forskolin, a novel diterpene activator of adenylate cyclase in membranes and intact cells, activates the enzyme in membranes from mutant cyc-S49 murine lymphoma cells and the soluble enzyme from rat testes. Each of these enzymes consists only of the catalytic subunit and does not have a functional guanine nucleotide-binding protein. In both cases forskolin converts the manganese-dependent enzymes to a form which does not require manganese for activity. Forskolin can also stimulate a detergent-solubilized preparation of adenylate cyclase from rat cerebral cortex. Activation of adenylate cyclase by forskolin is therefore not dependent on a perturbation of membrane structure nor does it require a functional guanine nucleotide-binding subunit.