Dual-probe molecular MRI for the in vivo characterization of atherosclerosis in a mouse model: Simultaneous assessment of plaque inflammation and extracellular-matrix remodeling.

Molecular MRI is a promising in-vivo modality to detect and quantify morphological and molecular vessel-wall changes in atherosclerosis. The combination of different molecular biomarkers may improve the risk stratification of patients. This study aimed to investigate the feasibility of simultaneous visualization and quantification of plaque-burden and inflammatory activity by dual-probe molecular MRI in a mouse-model of progressive atherosclerosis and in response-to-therapy. Homozygous apolipoprotein E knockout mice (ApoE-/-) were fed a high-fat-diet (HFD) for up to four-months prior to MRI of the brachiocephalic-artery. To assess response-to-therapy, a statin was administered for the same duration. MR imaging was performed before and after administration of an elastin-specific gadolinium-based and a macrophage-specific iron-oxide-based probe. Following in-vivo MRI, samples were analyzed using histology, immunohistochemistry, inductively-coupled-mass-spectrometry and laser-inductively-coupled-mass-spectrometry. In atherosclerotic-plaques, intraplaque expression of elastic-fibers and inflammatory activity were not directly linked. While the elastin-specific probe demonstrated the highest accumulation in advanced atherosclerotic-plaques after four-months of HFD, the iron-oxide-based probe showed highest accumulation in early atherosclerotic-plaques after two-months of HFD. In-vivo measurements for the elastin and iron-oxide-probe were in good agreement with ex-vivo histopathology (Elastica-van-Giesson stain: y = 298.2 + 5.8, R2 = 0.83, p < 0.05; Perls' Prussian-blue-stain: y = 834.1 + 0.67, R2 = 0.88, p < 0.05). Contrast-to-noise-ratio (CNR) measurements of the elastin probe were in good agreement with ICP-MS (y = 0.11x-11.3, R² = 0.73, p < 0.05). Late stage atherosclerotic-plaques displayed the strongest increase in both CNR and gadolinium concentration (p < 0.05). The gadolinium probe did not affect the visualization of the iron-oxide-probe and vice versa. This study demonstrates the feasibility of simultaneous assessment of plaque-burden and inflammatory activity by dual-probe molecular MRI of progressive atherosclerosis. The in-vivo detection and quantification of different MR biomarkers in a single scan could be useful to improve characterization of atherosclerotic-lesions.

Effect of Statin Treatment vs Usual Care on Primary Cardiovascular Prevention Among Older Adults: The ALLHAT-LLT Randomized Clinical Trial.

Importance: While statin therapy for primary cardiovascular prevention has been associated with reductions in cardiovascular morbidity, the effect on all-cause mortality has been variable. There is little evidence to guide the use of statins for primary prevention in adults 75 years and older. Objectives: To examine statin treatment among adults aged 65 to 74 years and 75 years and older when used for primary prevention in the Lipid-Lowering Trial (LLT) component of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT-LLT). Design, Setting, and Participants: Post hoc secondary data analyses were conducted of participants 65 years and older without evidence of atherosclerotic cardiovascular disease; 2867 ambulatory adults with hypertension and without baseline atherosclerotic cardiovascular disease were included. The ALLHAT-LLT was conducted from February 1994 to March 2002 at 513 clinical sites. Interventions: Pravastatin sodium (40 mg/d) vs usual care (UC). Main Outcomes and Measures: The primary outcome in the ALLHAT-LLT was all-cause mortality. Secondary outcomes included cause-specific mortality and nonfatal myocardial infarction or fatal coronary heart disease combined (coronary heart disease events). Results: There were 1467 participants (mean [SD] age, 71.3 [5.2] years) in the pravastatin group (48.0% [n = 704] female) and 1400 participants (mean [SD] age, 71.2 [5.2] years) in the UC group (50.8% [n = 711] female). The baseline mean (SD) low-density lipoprotein cholesterol levels were 147.7 (19.8) mg/dL in the pravastatin group and 147.6 (19.4) mg/dL in the UC group; by year 6, the mean (SD) low-density lipoprotein cholesterol levels were 109.1 (35.4) mg/dL in the pravastatin group and 128.8 (27.5) mg/dL in the UC group. At year 6, of the participants assigned to pravastatin, 42 of 253 (16.6%) were not taking any statin; 71.0% in the UC group were not taking any statin. The hazard ratios for all-cause mortality in the pravastatin group vs the UC group were 1.18 (95% CI, 0.97-1.42; P = .09) for all adults 65 years and older, 1.08 (95% CI, 0.85-1.37; P = .55) for adults aged 65 to 74 years, and 1.34 (95% CI, 0.98-1.84; P = .07) for adults 75 years and older. Coronary heart disease event rates were not significantly different among the groups. In multivariable regression, the results remained nonsignificant, and there was no significant interaction between treatment group and age. Conclusions and Relevance: No benefit was found when pravastatin was given for primary prevention to older adults with moderate hyperlipidemia and hypertension, and a nonsignificant direction toward increased all-cause mortality with pravastatin was observed among adults 75 years and older. Trial Registration: clinicaltrials.gov Identifier: NCT00000542.

Semiparametric methods for multistate survival models in randomised trials.

Transform methods have proved effective for networks describing a progression of events. In semi-Markov networks, we calculated the transform of time to a terminating event from corresponding transforms of intermediate steps. Saddlepoint inversion then provided survival and hazard functions, which integrated, and fully utilised, the network data. However, the presence of censored data introduces significant difficulties for these methods. Many participants in controlled trials commonly remain event-free at study completion, a consequence of the limited period of follow-up specified in the trial design. Transforms are not estimable using nonparametric methods in states with survival truncated by end-of-study censoring. We propose the use of parametric models specifying residual survival to next event. As a simple approach to extrapolation with competing alternative states, we imposed a proportional incidence (constant relative hazard) assumption beyond the range of study data. No proportional hazards assumptions are necessary for inferences concerning time to endpoint; indeed, estimation of survival and hazard functions can proceed in a single study arm. We demonstrate feasibility and efficiency of transform inversion in a large randomised controlled trial of cholesterol-lowering therapy, the Long-Term Intervention with Pravastatin in Ischaemic Disease study. Transform inversion integrates information available in components of multistate models: estimates of transition probabilities and empirical survival distributions. As a by-product, it provides some ability to forecast survival and hazard functions forward, beyond the time horizon of available follow-up. Functionals of survival and hazard functions provide inference, which proves sharper than that of log-rank and related methods for survival comparisons ignoring intermediate events.

Cost effectiveness of targeted high-dose atorvastatin therapy following genotype testing in patients with acute coronary syndrome.

BACKGROUND: Results from the PROVE IT trial suggest that patients with acute coronary syndrome (ACS) treated with atorvastatin 80 mg/day (A80) have significantly lower rates of cardiovascular events compared with patients treated with pravastatin 40 mg/day (P40). In a genetic post hoc substudy of the PROVE IT trial, the rate of event reduction was greater in carriers of the Trp719Arg variant in kinesin family member 6 protein (KIF6) than in noncarriers. We assessed the cost effectiveness of testing for the KIF6 variant followed by targeted statin therapy (KIF6 Testing) versus not testing patients (No Test) and treating them with P40 or A80 in the USA from a payer perspective. METHODS: A Markov model was developed in which 2-year event rates from PROVE IT were extrapolated over a lifetime horizon. Costs and utilities were derived from published literature. All costs were in 2010 US dollars except the cost of A80, which was in 2012 US dollars because the generic formulation was available in 2012. Expected costs and quality-adjusted life-years (QALYs) were estimated for each strategy over a lifetime horizon. RESULTS: Lifetime costs were US$31,700; US$37,100 and US$41,300 for No Test P40, KIF6 Testing and No Test A80 strategies, respectively. The No Test A80 strategy was associated with more QALYs (9.71) than the KIF6 Testing (9.69) and No Test P40 (9.57) strategies. No Test A80 had an incremental cost-effectiveness ratio (ICER) of US$232,100 per QALY gained compared with KIF6 Testing. KIF6 Testing had an ICER of US$45,300 per QALY compared with No Test P40. CONCLUSIONS: Testing ACS patients for KIF6 carrier status may be a cost-effective strategy at commonly accepted thresholds. Treating all patients with A80 is more expensive than treating patients on the basis of KIF6 results, but the modest gain in QALYs is achieved at a cost/QALY that is generally considered unacceptable compared with the KIF6 Testing strategy. Compared with treating all patients with P40, the KIF6 Testing strategy had an ICER below US$50,000 per QALY. The conclusions from this study are sensitive to the price of generic A80 and the effect on adherence of knowing KIF6 carrier status. The results were based on a post hoc substudy of the PROVE IT trial, which was not designed to test the effectiveness of KIF6 testing.

Bilayered transmucosal drug delivery system of pravastatin sodium: statistical optimization, in vitro, ex vivo, in vivo and stability assessment.

The objective of the present study was to develop a mucoadhesive sustained release bilayered buccal patch of pravastatin sodium using Eudragit S100 as the base matrix so as to surmount hepatic first pass metabolism and gastric instability of the drug. A 3² full factorial design was employed to study the effect of independent variables viz. levels of HPMC K4M and carbopol 934P on % cumulative drug release, mucoadhesion time and mucoadhesive force. Amount of carbopol 934P and HPMC K4M significantly influenced characteristics like swelling index, in vitro mucoadhesive force, drug release, and mucoadhesion time. In vitro evaluation revealed that formulations exhibited satisfactory technological parameters. The mechanism of drug release was found to be non-Fickian diffusion. Different permeation enhancers were investigated to improve the permeation of drug from the optimized patches (F9) across the buccal mucosa. Formulation [F9 (P3)] containing 4% (v/v) dimethyl sulfoxide exhibited desirable permeation of drug. Histopathological studies performed using goat buccal mucosa revealed no mucosal damage. Bioavailability studies in rabbits demonstrated that [F9 (P3)] significantly higher C(max) (67.34 ± 3.58 ng/ml) and AUC0₋∞ (350.27 ± 9.59 ng/ml×h) (p < 0.05) of pravastatin sodium from optimized patch than IR tablet (C(max) 58.73 ± 4.63 ng/ml and AUC0₋∞ 133.80 ± 8.25 ng/ml×h). Formulation [F9 (P3)] showed sustained drug plasma concentration over a period of 10 h which was significantly longer than oral tablet (p < 0.05). Stability studies as per ICH guidelines established physical stability of the patch and chemical stability drug. The present study established potential of the optimized mucoadhesive buccal patches to circumvent the hepatic first-pass metabolism, gastric instability and to improve bioavailability of pravastatin sodium.

Coronary plaque regression and lifestyle modification in patients treated with pravastatin. - Assessment mainly by daily aerobic exercise and an increase in the serum level of high-density lipoprotein cholesterol -.

BACKGROUND: The purpose of this study was to explore the effect of lifestyle modification, mainly daily aerobic exercise, on coronary atherosclerosis in patients with coronary artery disease (CAD). METHODS AND RESULTS: A 6-month prospective observational study was conducted with 84 CAD patients receiving pravastatin treatment in order to evaluate the relationship between lifestyle modification, in particular aerobic exercise, and plaque volume as assessed by intravascular ultrasound (IVUS). Lifestyle during the study period was assessed by the-lifestyle modification score. A significant decrease in plaque volume by 12.9% was observed after 6 months of pravastatin therapy (P<0.0001 vs baseline). The change in plaque volume correlated with the change in the serum level of high-density lipoprotein cholesterol (HDL-C) (r=-0.549, P<0.0001), non-HDL-C (r=0.248, P=0.03), low-density lipoprotein cholesterol/HDL-C (r=0.505, P<0.0001), apolipoprotein (apo) A-1 (r=-0.335, P=0.007) and apoB/apoA-1 (r=0.335, P=0.007), and lifestyle modification score (r=-0.616, P<0.0001). There was a clear positive correlation between a change in the serum HDL-C level and lifestyle modification score. Multivariate regression analysis revealed that the increase in serum HDL-C level and lifestyle modification score were independent predictors of coronary plaque regression. CONCLUSIONS: An appropriate combination of statin therapy and lifestyle modification, in particular, physical activity, may result in coronary plaque regression. This combined treatment strategy, inducing an increase of the serum HDL-C, may contribute to coronary plaque regression.

Cost-effectiveness analysis of rosuvastatin versus atorvastatin, simvastatin, and pravastatin from a Canadian health system perspective.

OBJECTIVE: The primary objective of this study was to assess the cost-effectiveness of the most commonly prescribed doses of rosuvastatin, atorvastatin, simvastatin, and pravastatin for managing various lipid parameters in patients with hypercholesterolemia over a 1-year time horizon from a Canadian health care perspective. METHODS: Incremental cost-effectiveness ratios (ICERs) were estimated for branded rosuvastatin compared with branded atorvastatin, generic simvastatin, and generic pravastatin in patients with hypercholesterolemia in terms of percent reduction in low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio, as well as in TC, HDL-C, triglycerides (TG), apolipoprotein (Apo) B, the ApoB/ApoA-I ratio, and attainment of the Canadian LDL-C goal. The pharmacoeconomic model was constructed for a 1-year time horizon using efficacy data from a randomized, open-label trial including 2268 adults and the wholesale acquisition costs of branded rosuvastatin and atorvastatin and generic simvastatin and pravastatin in British Columbia. RESULTS: The most commonly prescribed doses of each of the 4 statins in British Columbia were as follows: rosuvastatin 10 mg (75.8% of all rosuvastatin doses); atorvastatin 10 and 20 mg (46.4% and 35.3%, respectively, of all atorvastatin doses); simvastatin 20 and 40 mg (42.5% and 31.8%, respectively, of all simvastatin doses); and pravastatin 20 and 40 mg (55.0% and 34.1%, respectively, of all pravastatin doses). Rosuvastatin 10 mg was dominant (ie, was more effective at a lower cost) relative to atorvastatin 10 and 20 mg, simvastatin 20 and 40 mg, and pravastatin 40 mg in terms of reductions in LDL-C, TC/ HDL-C ratio, TC, ApoB, and ApoB/ApoA-I ratio, increases in HDL-C, and attainment of the LDL-C goal. Compared with pravastatin 20 mg, the ICER per percent reduction in LDL-C, TC/HDL-C ratio, TC, TG, ApoB, or ApoB/ApoA-I or increase in HDL-C ranged from $3.89 to $26.07; the value for 1 additional patient achieving the LDL-C goal was $419.75. When the statin doses were aggregated based on the Canadian statin-utilization pattern, rosuvastatin was dominant relative to atorvastatin on all effectiveness measures evaluated. When rosuvastatin was compared with generic simvastatin and pravastatin, the annual costs for 1 additional patient achieving the LDL-C goal were $144.51 and $373.91, respectively. Based on the sensitivity analysis, rosuvastatin was associated with the highest probability of cost-effectiveness compared with the other statins over a broad range of monetary values per unit of clinical effect. CONCLUSION: When percent changes in lipid parameters and rates of LDL-C goal attainment were considered in patients with hypercholesterolemia in British Columbia, rosuvastatin 10 mg was more cost-effective than the most frequently used doses of atorvastatin (10 and 20 mg), generic simvastatin (20 and 40 mg), and generic pravastatin (20 and 40 mg).

Impact of high dose statin trials on hospital prescribers.

BACKGROUND: The PROVE-IT and REVERSAL studies established that an intensive 80 mg/day dose of atorvastatin was superior to pravastatin 40 mg/day for the secondary prevention of coronary heart disease (CHD) following acute coronary syndromes and in limiting the progression of coronary atherosclerosis. We have evaluated the impact of the results from these studies on statin prescribing by hospital doctors in the 2 years following their publication. METHODS AND RESULTS: Using a nationwide database, 18,894 patients receiving a total of 23,750 hospital discharge prescriptions for atorvastatin were identified between September 2002 and December 2005. From this cohort, patients newly commenced on, switched to, or dose titrated on atorvastatin by a hospital prescriber were identified. The mean daily atorvastatin dose on discharge was calculated for each month and the results were analysed using a segmented regression analysis. There was a significant and sustained increase in the mean atorvastatin dose used by hospital prescribers. This resulted in an increase of 12 mg, (95% CI 10.6, 13.4) in the mean dose prescribed by December 2005. This was attributable largely to a 16.4% (95% CI 13.5, 19.3), 17.2% (95% CI 14.0, 20.5) and 8.8% (95% CI 7.4, 10.2) increase in the prescribing of the 20 mg, 40 mg and 80 mg/day dosages, respectively. CONCLUSION: The PROVE-IT and REVERSAL studies have had a significant impact on hospital prescribers' choice of atorvastatin dose. It is likely that this has been the result of both the publication and effective promotion of results from these trials.

An approach to the residence time distribution for stochastic multi-compartment models.

Stochastic compartmental models are widely used in modeling processes such as drug kinetics in biological systems. This paper considers the distribution of the residence times for stochastic multi-compartment models, especially systems with non-exponential lifetime distributions. The paper first derives the moment generating function of the bivariate residence time distribution for the two-compartment model with general lifetimes and approximates the density of the residence time using the saddlepoint approximation. Then, it extends the distributional approach to the residence time for multi-compartment semi-Markov models combining the cofactor rule for a single destination and the analytic approach to the two-compartment model. This approach provides a complete specification of the residence time distribution based on the moment generating function and thus facilitates an easier calculation of high-order moments than the approach using the coefficient matrix. Applications to drug kinetics demonstrate the simplicity and usefulness of this approach.

Managed care trends in statin usage.

PURPOSE: HMG-CoA reductase inhibitors ("statins") have become the drug class of choice for the treatment of hyperlipidemia. Six product brands encompassing 20 dosage strengths have been available during the past two years. The objective of this review is to describe dosing trends for the six statin brands and to determine if and how these trends vary among managed care plans as a function of product market share. METHODOLOGY: Utilization of HMG-CoA reductase inhibitors was examined using the NDC Health Information Services (Phoenix, Ariz.) database for the two-year period ending December 2000. This database contains unit dispensing data at the dosage-strength level for 1,079 managed care plans. Trends in market share, mean daily dose, and dosage distribution of the six current statin brands were examined. The relationship of market share to mean dose was also examined for each brand. PRINCIPAL FINDINGS: Market share decreased for all statin brands during the two-year period, except for the two newest entries, atorvastatin (up 9.7 share points) and cerivastatin (up 4.6 share points). The mean dose of all statins increased during the two-year period. A statistically significant negative correlation between market share and mean dose was found for atorvastatin and a positive correlation was found for fluvastatin (P < 0.01). Furthermore, atorvastatin share was significantly correlated to lower mean doses of all other statin brands. That is, higher use of atorvastatin was associated with lower doses of all statin products. CONCLUSION: In developing a cost-management strategy, managed care organizations should take historical and anticipated market-share changes and dose-mix changes into account along with the product's clinical efficacy and total cost of care.

Effect of pravastatin-to-simvastatin conversion on low-density-lipoprotein cholesterol.

The effects of a pravastatin-to-simvastatin conversion program on low-density-lipoprotein (LDL) cholesterol levels were studied. Patients receiving pravastatin at a Veterans Affairs medical center were switched to simvastatin beginning in 1997. The dosage of simvastatin was based on the additional percent reduction in LDL cholesterol needed to achieve the goal specified by the National Cholesterol Education Program. The primary endpoint was the change in the percentage of patients meeting their LDL cholesterol goal at baseline and follow-up. Changes in lipid indices, the relative risk (RR) of coronary heart disease (CHD), and program costs were also evaluated. A total of 1032 patients completed the program. The mean +/- S.D. daily doses of pravastatin and simvastatin were 25.2 +/- 11.3 and 22.7 +/- 13.3 mg, respectively. Median baseline and follow-up LDL cholesterol concentrations were 116 and 99 mg/dL, respectively (p < 0.001). Overall, 44% of the patients met their LDL cholesterol goal while taking pravastatin, compared with 69% after conversion to simvastatin (p < 0.001). The predicted mean RR of a future CHD event (based on changes in serum lipids) was 0.87 (95% confidence interval, 0.83-0.91) four years after conversion. The total cost of the program was $40,644 in the first year, and there was a net saving thereafter. Therapeutic interchange between pravastatin and simvastatin increased the number of patients meeting their LDL cholesterol goal.

Therapeutic change of HMG-CoA reductase inhibitors in patients with coronary artery disease.

STUDY OBJECTIVE: To evaluate short-term outcomes when atorvastatin was substituted for pravastatin or simvastatin in patients with coronary artery disease. DESIGN: Open-label, fixed-dosage, one-way crossover from pravastatin and simvastatin to atorvastatin. SETTING: University-affiliated hospital and outpatient clinics. PATIENTS: Eighty patients with coronary artery disease with a minimum baseline low-density lipoprotein (LDL) above 130 mg/dl: 20 were treated with pravastatin 20 mg/day, 20 with pravastatin 40 mg/day, 20 with simvastatin 20 mg/day, and 20 with simvastatin 40 mg/day for a minimum of 6 months, with a prescription refill rate of 80% or greater. Intervention. Before crossover, patients had a fasting lipid profile determined and were questioned about side effects of pravastatin and simvastatin. All patients were switched to atorvastatin 10 mg/day. After 12 weeks of atorvastatin therapy, a repeat fasting lipid profile was obtained and patients were questioned about side effects with the drug. MEASUREMENTS AND MAIN RESULTS: Baseline demographic and clinical characteristics of the treatment groups were not significantly different with the exception of a lower baseline LDL in patients receiving pravastatin 20 mg/day. Baseline LDL values were as follows: pravastatin 20 mg/day, 158+/-26 mg/dl; pravastatin 40 mg/day, 176+/-22 mg/dl; simvastatin 20 mg/day, 177+/-27 mg/dl; and simvastatin 40 mg/day, 177+/-27 mg/dl. Reductions in LDL after treatment with pravastatin or simvastatin were as follows: pravastatin 20 mg/day, 22%; pravastatin 40 mg/day, 32%; simvastatin 20 mg/day, 33%; and simvastatin 40 mg/day, 38%. Patients achieving LDL goal with initial therapy were as follows: pravastatin 20 mg/day, 5%; pravastatin 40 mg/day, 5%; simvastatin 20 mg/day, 20%; and simvastatin 40 mg/day, 30%. After the switch to atorvastatin 10 mg/day, reductions in LDL were as follows: pravastatin 20 mg/day, 39% (p<0.001); pravastatin 40 mg/day, 38% (p<0.01); simvastatin 20 mg/day, 39% (p=0.04); and simvastatin 40 mg/day, 38% (p=0.83). Patients achieving LDL goals with atorvastatin 10 mg/day were as follows: pravastatin 20 mg/day, 60%; pravastatin 40 mg/day, 30%; simvastatin 20 mg/day, 25%; and simvastatin 40 mg/day, 30%. The frequency of side effects was similar for all three statins. Based on annual average wholesale price, atorvastatin 10 mg/day was more cost-effective than all pravastatin and simvastatin regimens. CONCLUSIONS: Therapeutic interchange from pravastatin 20 and 40 mg/day and simvastatin 20 mg/day to atorvastatin 10 mg/day was associated with both cost savings and significant reductions in LDL. The change from simvastatin 40 mg/day to atorvastatin 10 mg/day was associated with cost savings and an equivalent reduction in LDL.

Effective use of statins to prevent coronary heart disease.

Primary and secondary prevention trials have shown that use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (also known as statins) to lower an elevated low-density lipoprotein cholesterol level can substantially reduce coronary events and death from coronary heart disease. In 1987 and 1993, the National Cholesterol Education Program promulgated guidelines for cholesterol screening and treatment. Thus far, however, primary care physicians have inadequately adopted these guidelines in clinical practice. A 1991 study found that cholesterol screening was performed in only 23 percent of patients. Consequently, many patients with elevated low-density lipoprotein levels and a high risk of primary or recurrent ischemic events remain unidentified and untreated. A study published in 1998 found that fewer than 15 percent of patients with known coronary heart disease have low-density lipoprotein levels at the recommended level of below 100 mg per dL (2.60 mmol per L). By identifying patients with elevated low-density lipoprotein levels and instituting appropriate lipid-lowering therapy, family physicians could help prevent cardiovascular events and death in many of their patients.

[Pharmacoeconomic evaluation of pravastatin in coronary secondary prevention in patients with myocardial infarct or unstable angina pectoris. An analysis based on the LIPID Study]. / Pharmakoökonomische Bewertung von Pravastatin in der koronaren Sekundärprävention bei Patienten mit Myokardinfarkt oder instabiler Angina Pectoris. Eine Analyse auf der Grundlage der LIPID-Studie.

BACKGROUND: Secondary coronary prevention with lipid lowering drugs have become a major issue in health policy formulation due to the large upfront investment in drug therapy. The recently completed LIPID trial with pravastatin in secondary prevention immediately raise the question whether pravastatin might be cost-effective in Switzerland. METHODS: We conducted a cost-effectiveness analysis from the perspective of third party payers. The following costs were included in the analysis: daily treatment costs of pravastatin, non fatal myocardial infarction, coronary bypass operations and stroke. Life years gained was obtained by applying the declining exponential approximation of life expectancy. All calculations were standardized to 1000 treated patients. RESULTS: The net costs of treating 1000 patients (i.e. drug costs minus the costs of sequelae and interventions) are Fr. 3.6 Mio. In addition, a total of 430 life-years may be saved through treatment. The corresponding cost-effectiveness of pravastatin treatment is Fr. 8341 (nominal) Fr. 6985 (discounted). CONCLUSIONS: The results suggest that the cost-effectiveness of pravastatin in secondary prevention lie well within the threshold of other commonly accepted medical interventions and may be considered an economically viable approach for secondary coronary prevention.

International economic analysis of primary prevention of cardiovascular disease with pravastatin in WOSCOPS. West of Scotland Coronary Prevention Study.

AIMS: The results of the West of Scotland Coronary Prevention Study (WOSCOPS) demonstrated the clinical benefit of using pravastatin for the primary prevention of cardiovascular disease in hypercholesterolaemic men. To inform decision makers, who must also consider costs, this study assesses the economic efficiency of such an intervention in a broad range of countries. METHODS AND RESULTS: A generalized model of cardiovascular disease prevention was used to estimate the cost-effectiveness of primary prevention with pravastatin compared to diet alone. This model follows a cohort of hypercholesterolaemic men over a given period quantifying the effect in terms of the avoidance of cardiovascular disease based on treatment-specific risks derived from WOSCOPS data and extensive record-linkage data on disease-specific survival. Country-specific costs are accounted for by expressing all such parameters in terms of the ratio of monthly treatment to that of managing a myocardial infarction. Over a broad range of inputs the cost-effectiveness ratios remain below $25,000 per life years gained, regardless of country. Subgroups with even better economic efficacy can be defined on the basis of higher baseline risk. CONCLUSIONS: In contrast to some previous reports, this analysis based on trial data demonstrates that pravastatin provides not only an effective means of primary cardiovascular disease prevention, but also an efficient one.

Comparative efficacy and tolerability of low-dose pravastatin versus lovastatin in patients with hypercholesterolemia.

BACKGROUND: The HMG CoA reductase inhibitors have quickly become the most widely prescribed family of agents for the treatment of patients with elevated low-density lipoprotein (LDL) cholesterol. The incidence of side effects with these agents increases as the dose increases within the recommended dosage range. A lower dosage presumably would have a lower incidence of adverse effects. In addition, lower doses should translate into reduced drug costs. METHODS AND RESULTS: We compared the efficacy of 10 mg of pravastatin and 10 mg of lovastatin in a randomized, crossover design trial among 30 patients with hypercholesterolemia. At baseline, their total cholesterol and LDL cholesterol levels were 249.0 +/- 27.3 and 185.1 +/- 25.5 mg/dL. After 4 weeks of treatment with lovastatin, the total cholesterol and LDL cholesterol levels fell to 202.8 +/- 29.6 and 141.0 +/- 25.3 mg/dL, decreases of 19% and 24%, respectively. Four weeks of pravastatin treatment resulted in levels of 212.6 +/- 30.8 and 150.5 +/- 25.5 mg/dL, or 15% and 19%, respectively. CONCLUSIONS: There were highly significant changes in total cholesterol and LDL cholesterol levels with each agent and no differences in effect between the 2 agents. In 13 (43%) of the 30 patients, LDL levels were reduced to

Pravastatin alone and in combination with low-dose cholestyramine in patients with primary hypercholesterolemia and coronary artery disease.

This randomized, open-label study compared the cost efficiency of low-dose pravastatin combined with low-dose cholestyramine with high-dose pravastatin monotherapy in 59 patients with moderate hypercholesterolemia and coronary disease. Both regimes were effective in improving lipid profiles in these patients; however, low-dose combination therapy enhanced achievement in therapeutic goals and cost efficiency.

A retrospective drug utilization evaluation of antihyperlipidaemic agents in a medical centre in Taiwan.

OBJECTIVE: The purpose of this study was to retrospectively evaluate the prescribing of antihyperlipidaemic agents in an 800-bed medical centre in southern Taiwan. METHODS: A retrospective study based on reviewing medical records was conducted using a computerized database. We randomly selected 344 patients (age range 5-85 years) who received an antihyperlipidaemic agent between 1 April 1994 and 30 September 1994 and reviewed their medical records. All the related data from the date when the antihyperlipidaemic agent was first prescribed to 31 December 1994 was assessed. Usage guidelines for antihyperlipidaemic agents were defined by referring to the literature and specialist opinion. RESULTS: Two hundred and twenty-two patients (64.5%) were treated with antihyperlipidaemic agents in accordance with the usage guidelines. In addition, most of the treatments complied with the regulations laid down by related health insurance programmes. The other 122 cases (35.5%) failed to meet any of the indications of the usage guidelines. Only 102 patients (29.7%) had their baseline lipid profiles examined and 117 patients (34%) had their baseline liver function tested. Over all, very few cases had lipid profiles and liver function tests every 3 months while taking antihyperlipidaemic agents. Patients who had been prescribed antihyperlipidaemic agents for more than 1 year were evaluated to assess the effectiveness of their pharmacological therapy. The prescribed doses were found to be lower than recommended in the general literature except for patients who received lovastatin and pravastatin. CONCLUSIONS: There are many treatment guidelines for hypercholesterolaemia in north America and Europe. This study revealed that a large proportion of antihyperlipidaemic agents used in our patient population did not comply with these general recommendations. Although the reasons for not complying with usage guidelines need to be further investigated, our study findings may well serve as the basis for further quality management and pharmacoeconomic analysis.