Effect of statins on a wide range of health outcomes: a cohort study validated by comparison with randomized trials

Statins, cognition, and dementia—systematic review and methodological commentary

Firm conclusions about whether mid-life or long-term statin use has an impact on cognitive decline and dementia remain elusive. Here, our objective was to systematically review, synthesize and critique the epidemiological literature that examines the relationship between statin use and cognition, so as to assess the current state of knowledge, identify gaps in our understanding, and make recommendations for future research. We summarize the findings of randomized controlled trials (RCTs) and observational studies, grouped according to study design. We discuss the methods for each, and consider likely sources of bias, such as reverse causation and confounding. Although observational studies that considered statin use at or near the time of dementia diagnosis suggest a protective effect of statins, these findings could be attributable to reverse causation. RCTs and well-conducted observational studies of baseline statin use and subsequent cognition over several years of follow-up do not support a causal preventative effect of late-life statin use on cognitive decline or dementia. Given that much of the human research on statins and cognition in the future will be observational, careful study design and analysis will be essential.

Effectiveness and cost-effectiveness of interferon beta and glatiramer acetate in the UK Multiple Sclerosis Risk Sharing Scheme at 6 years: a clinical cohort study with natural history comparator

BACKGROUND

In 2002, the UK's National Institute for Clinical Excellence (NICE) concluded that interferon beta and glatiramer acetate would be cost effective as disease-modifying therapies (DMTs) for multiple sclerosis only if the short-term disability benefits reported in clinical trials were maintained. The UK Multiple Sclerosis Risk Sharing Scheme (RSS) was established to assess whether disability progression was consistent with a cost-effectiveness target of £36 000 per quality-adjusted life-year projected over 20 years. We aimed to evaluate the long-term effectiveness and cost-effectiveness of these DMTs by comparing a cohort of patients with relapsing-remitting multiple sclerosis enrolled in the UK RSS with a natural history cohort from British Columbia, Canada.

METHODS

In our clinical cohort we included patients starting a DMT who were enrolled in the UK RSS who had relapsing multiple sclerosis at baseline and had at least one further clinical assessment. In our control cohort we included patients in the British Columbia multiple sclerosis database (BCMS; data collection 1980-96) who met the same eligibility criteria as for the RSS cohort. We compared disability progression at 6 years for RSS patients with untreated progression modelled from BCMS patients using continuous Markov and multilevel models. The primary outcomes were the progression ratio (treated vs untreated) measured both in Expanded Disability Status Scale (EDSS) score and utility. A ratio of less than 100% for EDSS implied slower than expected progression on treatment compared with off treatment; a utility ratio of 62% or less implied that the DMTs were cost effective.

FINDINGS

5610 patients starting a DMT were enrolled in the UK RSS between Jan 14, 2002, and July 13, 2005 (72 sites), of whom 4137 were included in our clinical cohort. We included 898 BCMS patients in the control cohort who met the RSS inclusion criteria and had at least one EDSS score after baseline. RSS patients had a mean follow-up of 5·1 years (SD 1·4). Both models showed slower EDSS progression than predicted for untreated controls (Markov model, 75·8% [95% CI 71·4-80·2]; multilevel model, 60·0% [56·6-63·4]). Utility ratios were consistent with cost-effectiveness (Markov model, 58·5% [95% CI 54·2-62·8]; multilevel model, 57·1% [53·0-61·2]).

INTERPRETATION

Findings from this large observational study of treatment with interferon beta or glatiramer acetate provide evidence that their effects on disability in patients with relapsing-remitting multiple sclerosis are maintained and cost effective over 6 years. Similar modelling approaches could be applied to other chronic diseases for which long-term controlled trials are not feasible.

FUNDING

Health Departments of England, Wales, Scotland, and Northern Ireland, Biogen Idec, Merck Serono, Bayer Schering Pharmaceuticals, Teva Pharmaceuticals Industries, UK National Institute of Health Research's Health Technology Assessment Programme.

Statins, aspirin and risk of venous thromboembolic events in breast cancer patients

Venous thromboembolic events (VTE's) are associated with decreased survival in breast cancer patients. Studies suggested that statins reduce the risk of VTE's in the general population. Low dose Aspirin reduces risk of VTE's in high risk populations. The Breast Cancer in Northern Israel Study is a case-control study of consecutive breast cancer cases diagnosed in northern Israel and matched controls. The present analysis was limited to cases with breast cancer enrolled in the study. Data was extracted from Clalit Health Services (CHS) database and from computerized pharmacy records. Out of 3,585 patients enrolled, 261 (7.3%) had a VTE during median follow up of 4.2 years. The 1 and 2 year cumulative incidence was 2.64 and 3.65%. 55.7% of patients used statins, predominantly simvastatin (75.8%). 44.5% used aspirin. In multivariate analysis neither statins nor aspirin use was associated with a reduced risk for a VTE. Unadjusted HR for statin and aspirin was 1.461 (1.018-2.096) and 1.293 (0.846-1.976), respectively, and the adjusted HR were 0.86 (0.648-1.14) and 1.013 (0.737-1.392). Results were similar when only simvastatin use was assessed. Metastatic disease, chemotherapy, age, BMI and presence of comorbidities were significantly associated with risk of VTE's. Our study is the first to look at the effect of statins and aspirin on the incidence of VTE's in patients with breast cancer. In our cohort, statin and aspirin use did not decrease the risk for a VTE. Our results might be explained by use of low potency statins (simvastatin and pravastatin) and by alternate mechanisms for VTE formation in patients with cancer.

Statins for age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a progressive late onset disorder of the macula affecting central vision. Age-related macular degeneration is the leading cause of blindness in people over 65 years in industrialized countries. Recent epidemiologic, genetic, and pathological evidence has shown AMD shares a number of risk factors with atherosclerosis, leading to the hypothesis that statins may exert protective effects in AMD.

OBJECTIVES

The objective of this review was to examine the effectiveness of statins compared with other treatments, no treatment, or placebo in delaying the onset and progression of AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to June 2014), PubMed (January 1946 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 5 June 2014.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared statins with other treatments, no treatment, or placebo in participants who were either susceptible to or diagnosed as having early stages of AMD.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. Two authors independently evaluated the search results against the selection criteria, abstracted data, and assessed risk of bias. We did not perform meta-analysis due to heterogeneity in the interventions and outcomes among the included studies.

MAIN RESULTS

Two RCTs with 144 total participants met the selection criteria. Both trials compared simvastatin versus placebo in older people (> 50 or 60 years) with high risk of developing AMD (drusen present on examination). The larger trial with 114 participants was conducted in Australia and used a higher dose (40 mg daily) of simvastatin for three years. Participants and study personnel in this trial were adequately masked; however, data were missing for 30% of participants at three years follow-up. The smaller trial of 30 participants was conducted in Italy and used a lower dose (20 mg) of simvastatin for three months. This trial reported insufficient details to assess the risk of bias.Neither trial reported data for change in visual acuity. Analysis of 30 participants in the smaller trial did not show a statistically significant difference between the simvastatin and placebo groups in visual acuity values at three months of treatment (decimal visual acuity 0.21 ± 0.56 in simvastatin group and 0.19 ± 0.40 in placebo group) or 45 days after the completion of treatment (decimal visual acuity 0.20 ± 0.50 in simvastatin group and 0.19 ± 0.48 in placebo group). The lack of a difference in visual acuity was not explained by lens or retina status, which remained unchanged during and after the treatment period for both groups.Preliminary analyses of 42 participants who had completed 12 months follow-up in the larger trial did not show a statistically significant difference between simvastatin and the placebo groups for visual acuity, drusen score, or visual function (effect estimates and confidence intervals were not available). Complete data for these outcomes at three years follow-up were not reported. At three years, the effect of simvastatin in slowing progression of AMD compared with placebo was uncertain (odds ratio 0.51, 95% confidence interval 0.23 to 1.09).One trial did not report adverse outcomes. The second trial reported no difference between groups in terms of adverse events such as death, muscle aches, and acute hepatitis.

AUTHORS' CONCLUSIONS

Evidence from currently available RCTs is insufficient to conclude that statins have a role in preventing or delaying the onset or progression of AMD.

Statins for primary prevention of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is common in clinical practice. The efficacy of statins in the primary prevention of VTE remains unproven. This is an update of the review first published in 2011.

OBJECTIVES

To assess the efficacy of statins in the primary prevention of VTE.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases (PVD) Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and CENTRAL (2014, Issue 1).

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed statins in the primary prevention of VTE were considered. The outcomes we evaluated were the rates of VTE, cardiovascular and cerebrovascular events, death and adverse events. Two authors (L Li, JH Tian) independently selected RCTs against the inclusion criteria. Disagreements were resolved by discussion with a third author (KH Yang).

DATA COLLECTION AND ANALYSIS

Data extraction was independently carried out by two authors (L Li, JH Tian). Disagreements were resolved by discussion with a third author (PZ Zhang). Two authors (L Li, JH Tian) independently assessed the risk of bias according to a standard quality checklist provided by the PVD Group.

MAIN RESULTS

For this update we included one RCT with 17,802 participants that assessed rosuvastatin compared with placebo for the prevention of VTE. The quality of the evidence was moderate because of imprecision, as the required sample size for the outcomes of this review was not achieved. Analysis showed that when compared with placebo rosuvastatin reduced the incidence of VTE (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.86) and deep vein thrombosis (DVT) (OR 0.45, 95% CI 0.25 to 0.79), the risk of any (fatal and non-fatal) myocardial infarction (MI) (OR 0.45, 95% CI 0.30 to 0.69), and any (fatal and non-fatal) stroke (OR 0.51, 95% CI 0.34 to 0.78). There was no difference in the incidence of pulmonary embolism (PE) (OR 0.77, 95% CI 0.41 to 1.46), fatal MI (OR 1.50, 95% CI 0.53 to 4.22), fatal stroke (OR 0.30, 95% CI 0.08 to 1.09) or death after VTE (OR 0.50, 95% CI 0.20 to 1.24). The incidence of any serious adverse events was no different between the rosuvastatin and placebo groups (OR 1.07, 95% CI 0.95 to 1.20).

AUTHORS' CONCLUSIONS

Available evidence showed that rosuvastatin was associated with a reduced incidence of VTE, but the evidence was limited to a single RCT and any firm conclusions and suggestions could be not drawn. Randomised controlled trials of statins (including rosuvastatin) are needed to evaluate their efficacy in the prevention of VTE.

Statins, mood, sleep, and physical function: a systematic review

PURPOSE

We aimed to evaluate the effects of statins on mood, sleep, and physical function.

METHODS

We performed a systematic computer-aided search of MEDLINE/PubMed, EMBASE, and the Cochrane Central Register and augmented this search by scrutinizing reference lists and making inquiries among colleagues and experts in the field. All patient populations and study types were considered. We selected studies of statin therapy compared with no statin or placebo. Outcome measures included mood, sleep, and physical function.

RESULTS

Thirty-four studies were included in qualitative synthesis. Seven of eight (88 %) observational studies, 4/6 (66 %) randomized trials with mood as a primary endpoint (487 total participants; exposure 4 weeks to 1 year), and 3/3 (100 %) randomized trials with mood as a secondary endpoint (2,851 total participants; exposure 1-4 years) were not compatible with a negative mood effect of statins. Comparatively, fewer studies examined statin effects on sleep and physical function. Studies reporting negative effects contained potential sources of bias, including multiple testing or lack of adjustment for confounders in observational studies, and failure to prespecify outcomes or report blinding in trials.

CONCLUSIONS

A limited body of available evidence is most compatible with no adverse effect of statins on quality of life measures, namely, mood, sleep, and physical function. Studies suggesting such effects suffer from an increased risk of bias. High-quality, prospective, and adequately powered studies are needed, especially in the domains of sleep and physical function, with careful attention to patients who may be most vulnerable to adverse effects.

Long-term statin use and dementia risk in Taiwan

BACKGROUND

The effect of statin use on dementia risk remains unclear. This study aims to examine the association between long-term statin use and dementia risk.

METHODS

A nest case-control study within a nationwide representative population-based cohort. Individuals aged 50 years and older participating in Taiwan's National Health Insurance program between 1998 and 2009 were enrolled. A total of 9257 patients with at least 3 outpatient or 1 inpatient claims records for dementia were identified. Comparison patients were selected at a 1:2 ratio from age- and sex-matched participants without dementia. The cumulative period and average daily dosages of statins, fibrates, and other lipid-lowering agents were measured.

RESULTS

The authors found a duration-response relationship, as dementia risk decreased by 9% per year of treatment of statins (adjusted odds ratio = 0.91; 95% confidence interval, 0.85-0.97). Use of high average dose statins for more than 1 year was associated with a lower risk of dementia than use of low average dose. However, there was no significant difference in dementia risks between lipophilic and hydrophilic statins. Fibrates or other lipid-lowering agents had no significant association with dementia risk.

CONCLUSION

Our results suggest that long-term use of statin is associated with a reduced dementia risk.

Statins in oncological research: from experimental studies to clinical practice

Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors are commonly used drugs in the treatment of dyslipidemias, primarily raised cholesterol. Recently, many epidemiological and preclinical studies pointed to anti-tumor properties of statins, including anti-proliferative activities, apoptosis, decreased angiogenesis and metastasis. These processes play an important role in carcinogenesis and, therefore, the role of statins in cancer disease is being seriously discussed among oncologists. Anti-neoplastic properties of statins combined with an acceptable toxicity profile in the majority of individuals support their further development as anti-tumor drugs. The mechanism of action, current preclinical studies and clinical efficacy of statins are reviewed in this paper. Moreover, promising results have been reported regarding the statins' efficacy in some cancer types, especially in esophageal and colorectal cancers, and hepatocellular carcinoma. Statins' hepatotoxicity has traditionally represented an obstacle to the prescription of this class of drugs and this issue is also discussed in this review.

Sources of heterogeneity in case-control studies on associations between statins, ACE-inhibitors, and proton pump inhibitors and risk of pneumonia

The heterogeneity in case-control studies on the associations between community-acquired pneumonia (CAP) and ACE-inhibitors (ACEi), statins, and proton pump inhibitors (PPI) hampers translation to clinical practice. Our objective is to explore sources of this heterogeneity by applying a common protocol in different data settings. We conducted ten case-control studies using data from five different health care databases. Databases varied on type of patients (hospitalised vs. GP), level of case validity, and mode of exposure ascertainment (prescription or dispensing based). Identified CAP patients and controls were matched on age, gender, and calendar year. Conditional logistic regression was used to calculate odds ratios (OR) for the associations between the drugs of interest and CAP. Associations were adjusted by a common set of potential confounders. Data of 38,742 cases and 118,019 controls were studied. Comparable patterns of variation between case-control studies were observed for ACEi, statins and PPI use and pneumonia risk with adjusted ORs varying from 1.04 to 1.49, 0.82 to 1.50 and 1.16 to 2.71, respectively. Overall, higher ORs were found for hospitalised CAP patients matched to population controls versus GP CAP patients matched to population controls. Prevalence of drug exposure was higher in dispensing data versus prescription data. We show that case-control selection and methods of exposure ascertainment induce bias that cannot be adjusted for and to a considerable extent explain the heterogeneity in results obtained in case-control studies on statins, ACEi and PPIs and CAP. The common protocol approach helps to better understand sources of variation in observational studies.

Can analyses of electronic patient records be independently and externally validated? The effect of statins on the mortality of patients with ischaemic heart disease: a cohort study with nested case-control analysis

OBJECTIVE

To conduct a fully independent and external validation of a research study based on one electronic health record database, using a different electronic database sampling the same population.

DESIGN

Using the Clinical Practice Research Datalink (CPRD), we replicated a published investigation into the effects of statins in patients with ischaemic heart disease (IHD) by a different research team using QResearch. We replicated the original methods and analysed all-cause mortality using: (1) a cohort analysis and (2) a case-control analysis nested within the full cohort.

SETTING

Electronic health record databases containing longitudinal patient consultation data from large numbers of general practices distributed throughout the UK.

PARTICIPANTS

CPRD data for 34 925 patients with IHD from 224 general practices, compared to previously published results from QResearch for 13 029 patients from 89 general practices. The study period was from January 1996 to December 2003.

RESULTS

We successfully replicated the methods of the original study very closely. In a cohort analysis, risk of death was lower by 55% for patients on statins, compared with 53% for QResearch (adjusted HR 0.45, 95% CI 0.40 to 0.50; vs 0.47, 95% CI 0.41 to 0.53). In case-control analyses, patients on statins had a 31% lower odds of death, compared with 39% for QResearch (adjusted OR 0.69, 95% CI 0.63 to 0.75; vs OR 0.61, 95% CI 0.52 to 0.72). Results were also close for individual statins.

CONCLUSIONS

Database differences in population characteristics and in data definitions, recording, quality and completeness had a minimal impact on key statistical outputs. The results uphold the validity of research using CPRD and QResearch by providing independent evidence that both datasets produce very similar estimates of treatment effect, leading to the same clinical and policy decisions. Together with other non-independent replication studies, there is a nascent body of evidence for wider validity.

Serious statin-associated myotoxicity and rhabdomyolysis in Aboriginal and Torres Strait Islanders: a case series

BACKGROUND

Statins are associated with skeletal muscle adverse effects. These are generally considered mild and reversible, with more severe toxicity occurring rarely. There is little known regarding statin myotoxicity in Aboriginal and Torres Strait Islander Australians who are at high cardiovascular risk and likely to receive statins.

AIMS

To describe features of serious statin-associated myotoxicity (SSAM) occurring in Indigenous Australians and increase awareness of this condition.

METHODS

Observational case series of SSAM in Aboriginal or Torres Strait Islanders. Cases were identified from personal clinical experience, referrals, reports to the Therapeutic Goods Administration, medical literature, an Internet search and reports from a histopathology laboratory. Information was collected onto a standardised data collection form.

RESULTS

Fifteen cases of serious myotoxicity in Aboriginal or Torres Strait Islanders exposed to statins were identified from 2006 to 2012. The mean age was 55 (range 35-69). Painless weakness was the most common presentation. Interacting drugs were involved in seven cases. Biopsies were done in eight cases, three showed inflammatory polymyositis and five necrotising myositis. Three patients died and two had permanent severe disability. Resolution of symptoms after statin cessation was variable.

CONCLUSIONS

SSAM has occurred in the Indigenous Australian population with some fatalities. Awareness of the potential for SSAM is essential for early recognition and effective management to reduce probability of avoidable catastrophic harm. Safe, as well as effective use of medication, is essential for optimum health outcomes. Effective pharmacovigilance and therapeutic risk management are important for Aboriginal and Torres Strait Islander Australians.

The effect of statin therapy on the incidence of infections: a retrospective cohort analysis

BACKGROUND

Statins have been postulated to prevent infection through immunomodulatory effects.

OBJECTIVES

To compare the incidence of infections in statin users to that in nonusers within the same health care system.

METHODS

This was a retrospective cohort study of patients enrolled as Tricare Prime or Plus in the San Antonio military multimarket. Statin users were patients who received a statin for at least 3 months between October 1, 2004 and September 30, 2005. Nonusers were patients who did not receive a statin within the study period (October 1, 2003-September 30, 2009). Inpatient and outpatient International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes were used to determine the incidence of infections during the follow-up period (October 1, 2005-September 30, 2009) via multivariable regression analysis and time to infection via Cox regression analysis.

RESULTS

Of 45,247 patients who met the study criteria, 12,981 (29%) were statin users and 32,266 were nonusers. After adjustments for age, gender, Charlson Comorbidity Score, tobacco use, alcohol abuse/dependence, health care utilization and use of specific medication classes, statin use was associated with an increased incidence of common infections (odds ratio [OR]: 1.13; 95% confidence interval [CI]: 1.06-1.19) but not influenza or fungal infections (OR: 1.06, 95% CI: 0.80-1.39; OR: 0.97; 95% CI: 0.91-1.04, respectively). Time-to-first infection was similar in statin users and nonusers in all infection categories examined.

CONCLUSIONS

Statin use was associated with an increased incidence of common infections but not influenza or fungal infections. This study does not support a protective role of statins in infection prevention; however, the influence of potential confounders cannot be excluded.

Simvastatin dose and risk of rhabdomyolysis: nested case-control study based on national health and drug dispensing data

BACKGROUND

Two randomised controlled trials have found a higher risk of rhabdomyolysis in users of 80 mg versus 20 mg simvastatin, but there is very limited information about the risk associated with other doses. We undertook a nested case-control study, using routinely collected national health and drug dispensing data, to estimate the relative and absolute risks of rhabdomyolysis resulting in hospital admission or death according to simvastatin dose.

METHODS AND RESULTS

The underlying study cohort comprised all patients (n=313,552) who initiated a new episode of simvastatin use in New Zealand between 1 May 2005 and 31 December 2009. Cases (n=29) were patients with a diagnosis of rhabdomyolysis after cohort entry, confirmed by hospital discharge letter or death records. Ten controls, matched by year of birth and sex, were randomly selected from the study cohort using risk set sampling. Current users of 40 mg simvastatin daily were about five times as likely to develop rhabdomyolysis as those taking 20mg; the adjusted odds ratio was 5.3 (95% CI 1.9-15.0). The absolute excess risk of rhabdomyolysis associated with the use of 40 mg versus 20mg was about 10 per 100,000 person-years; the crude incidence rates were 11.5 (95% CI 7.1-17.5) and 2.1 (95% CI 0.7-4.8) per 100,000 person-years respectively.

CONCLUSIONS

These findings provide reassurance that the absolute risk of rhabdomyolysis in a general population of simvastatin users is very low. Nonetheless, they also raise questions about the optimal simvastatin regimen to maximise cardiovascular benefits and minimise the risk of serious muscle injury.

Unintended effects of statins from observational studies in the general population: systematic review and meta-analysis

BACKGROUND

Efficacy of statins has been extensively studied, with much less information reported on their unintended effects. Evidence from randomized controlled trials (RCTs) on unintended effects is often insufficient to support hypotheses generated from observational studies. We aimed to systematically assess unintended effects of statins from observational studies in general populations with comparison of the findings where possible with those derived from randomized trials.

METHODS

Medline (1998 to January 2012, week 3) and Embase (1998 to 2012, week 6) were searched using the standard BMJ Cohort studies filter. The search was supplemented with reference lists of all identified studies and contact with experts in the field. We included prospective studies with a sample size larger than 1,000 participants, case control (of any size) and routine health service linkage studies of over at least one year duration. Studies in subgroups of patients or follow-up of patient case series were excluded, as well as hospital-based cohort studies.

RESULTS

Ninety studies were identified, reporting on 48 different unintended effects. Statins were associated with lower risks of dementia and cognitive impairment, venous thrombo-embolism, fractures and pneumonia, but these findings were attenuated in analyses restricted to higher quality studies (respectively: OR 0.74 (95% CI 0.62 to 0.87); OR 0.92 (95% CI 0.81 to 1.03); OR 0.97 (95% CI 0.88 to 1.05); OR 0.92 (95% CI 0.83 to 1.02)); and marked heterogeneity of effects across studies remained. Statin use was not related to any increased risk of depression, common eye diseases, renal disorders or arthritis. There was evidence of an increased risk of myopathy, raised liver enzymes and diabetes (respectively: OR 2.63 (95% CI 1.50 to 4.61); OR 1.54 (95% CI 1.47 to 1.62); OR 1.31 (95% CI 0.99 to 1.73)).

CONCLUSIONS

Our systematic review and meta-analyses indicate that high quality observational data can provide relevant evidence on unintended effects of statins to add to the evidence from RCTs. The absolute excess risk of the observed harmful unintended effects of statins is very small compared to the beneficial effects of statins on major cardiovascular events.

Statins, aspirin and risk of thromboembolic events in ovarian cancer patients

OBJECTIVES

Studies suggest that statins and low dose aspirin reduce risk of VTEs in the general population. We aimed to study the effect of these drugs on the incidence of VTEs in patients with ovarian cancer.

METHODS

Patients diagnosed with ovarian cancer between 2000 and 2011 were identified through the Clalit Health Services (CHS) chronic disease registry. Data were extracted from CHS database and from computerized pharmacy records. Use of medications was analyzed as a time dependent covariate in a Cox regression model.

RESULTS

Of 1746 patients 175 (10%) had a VTE during a median follow up of 3.13 years. 83 patients (5.6%) had a VTE within 2 years of diagnosis of ovarian cancer. Use of chemotherapy and stage 3 and 4 at presentation were associated with an increased risk for VTEs. Statins were used by 43.5% of the patients, and 32.3% used aspirin. Aspirin use was associated with a marginally significant reduction in incidence of VTEs within 2 years of diagnosis, HR 0.423 (95% CI 0.182-1.012, p-value 0.053). Statin use was not associated with risk of VTEs.

CONCLUSION

This is the first study looking at the effect of statins and aspirin on the incidence of VTEs in ovarian cancer patients. In our cohort, statins did not decrease the risk for a VTE and aspirin use was associated with a reduced risk which was marginally significant. Our results might be explained by use of low potency statins and by alternate mechanisms for VTE formation in cancer patients.

Clinical evidence of statin therapy in non-dyslipidemic disorders

The clinical benefits of statins are strongly related to their low density lipoprotein cholesterol (LDL-C) lowering properties. However, considering that the pharmacological target of statins, the 3-hydroxy-3-methyl-3-glutaryl coenzyme A (HMG-CoA) reductase, is one of the upstream enzyme of the mevalonate pathway, its inhibition may determine a substantial impoverishment of additional lipid moieties required for a proper cellular function. From this hypothesis, several experimental and clinical evidences have been reported indicating additional effects of statins beyond the LDL-C lowering, in particular anti-inflammatory and immunomodulatory effects. Thus statin therapy, indicated for hyperlipidemic patients for primary and secondary prevention of coronary heart disease (CHD) has begun to be considered effective in other diseases not necessarily linked to altered lipid profile. In the present review we summarized the current clinical evidence of the efficacy and safety profile of statins in a variety of diseases, such as rheumatoid arthritis, venous thromboembolism, liver diseases, polycystic ovary syndrome, and age-related macular degeneration. As discussed in the review, pending large, well designed, randomized trials, it is reasonable to conclude that there is no definitive evidence for the use of statins in the aforementioned diseases.

Statin use and fracture risk: can we quantify the healthy-user effect?

BACKGROUND

Numerous observational studies show that statin use is associated with lower risk of osteoporotic fractures. However, a causal relationship is not supported by data from randomized trials. Unmeasured confounding is implicated as a likely culprit for the controversy because of failure to measure and adjust for patient-level tendencies to engage in healthy behaviors. However, an alternative explanation is selection bias because of the inclusion of prevalent users of statins in the analysis. The relative importance of either bias has not been investigated in a quantitative sensitivity analysis.

METHODS

We conducted a systematic review to summarize the pattern of association between statin use and fracture risk in observational studies. Our objective was to quantify the magnitude of unmeasured confounding and selection bias in a sensitivity analysis.

RESULTS

In 17 published studies, the pooled relative risk for the association between current use of statins and fracture risk was 0.75 (95% confidence interval = 0.66-0.85). Upon adjustment for individual-level use of preventative health services, the pooled relative risk shifted by less than 5% on the log scale. However, a sensitivity analysis for selection bias revealed that moderate levels of bias could eliminate the association between statins and fracture risk.

CONCLUSIONS

It appears that confounding from unmeasured variables cannot explain the protective association between statins and fractures that has been observed in the literature.

The association between statin therapy during intensive care unit stay and the incidence of venous thromboembolism: a propensity score-adjusted analysis

Background

Studies have shown that statins have pleiotropic effects on inflammation and coagulation; which may affect the risk of developing venous thromboembolism (VTE). The objective of this study was to evaluate the association between statin therapy during intensive care unit (ICU) stay and the incidence of VTE in critically ill patients.

Methods

This was a post-hoc analysis of a prospective observational cohort study of patients admitted to the intensive care unit between July 2006 and January 2008 at a tertiary care medical center. The primary endpoint was the incidence of VTE during ICU stay up to 30 days. Secondary endpoint was overall 30-day hospital mortality. Propensity score was used to adjust for clinically and statistically relevant variables.

Results

Of the 798 patients included in the original study, 123 patients (15.4%) received statins during their ICU stay. Survival analysis for VTE risk showed that statin therapy was not associated with a reduction of VTE incidence (crude hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.28-1.54, P = 0.33 and adjusted HR 0.63, 95% CI 0.25-1.57, P = 0.33). Furthermore, survival analysis for hospital mortality showed that statin therapy was not associated with a reduction in hospital mortality (crude HR 1.26, 95% CI 0.95-1.68, P = 0.10 and adjusted HR 0.98, 95% CI 0.72-1.36, P = 0.94).

Conclusion

Our study showed no statistically significant association between statin therapy and VTE risk in critically ill patients. This question needs to be further studied in randomized control trials.

Statins and cognition: a systematic review and meta-analysis of short- and long-term cognitive effects

OBJECTIVE

To evaluate the effect of statins on short-term cognitive function and the long-term incidence of dementia.

PATIENTS AND METHODS

A systematic search was performed of MEDLINE, EMBASE, and the Cochrane Central Register from their inception to April 25, 2013. Adults with no history of cognitive dysfunction treated with statins were included from high-quality randomized controlled trials and prospective cohort studies after formal bias assessment.

RESULTS

Sixteen studies were included in qualitative synthesis and 11 in quantitative synthesis. Short-term trials did not show a consistent effect of statin therapy on cognitive end points. Digit Symbol Substitution Testing (a well-validated measure of cognitive function) was the most common short-term end point, with no significant differences in the mean change from baseline to follow-up between the statin and placebo groups (mean change, 1.65; 95% CI, -0.03 to 3.32; 296 total exposures in 3 trials). Long-term cognition studies included 23,443 patients with a mean exposure duration of 3 to 24.9 years. Three studies found no association between statin use and incident dementia, and 5 found a favorable effect. Pooled results revealed a 29% reduction in incident dementia in statin-treated patients (hazard ratio, 0.71; 95% CI, 0.61-0.82).

CONCLUSION

In patients without baseline cognitive dysfunction, short-term data are most compatible with no adverse effect of statins on cognition, and long-term data may support a beneficial role for statins in the prevention of dementia.

Statin use and markers of immunity in the Doetinchem cohort study

It has been suggested that statins can both stimulate and suppress the immune system, and thereby, may influence autoimmune diseases. Therefore, we studied effects of statins on innate and adaptive immunity, and self-tolerance by measuring serological levels of C-reactive protein (CRP), neopterin, immunoglobulin E (IgE) antibodies and the presence of autoantibodies (antinuclear antibodies (ANA) and IgM rheumatoid factor (RF)) in the general population. We conducted a nested case-control study within the population-based Doetinchem cohort. Data from health questionnaires, serological measurements and information on medication from linkage to pharmacy-dispensing records were available. We selected 332 statin users (cases) and 331 non-users (controls), matched by age, sex, date of serum collection, history of cardiovascular diseases, diabetes mellitus type II and stroke. Multivariate regression analyses were performed to estimate effect of statins on the immune system. The median level of CRP in statin users (1.28 mg/L, interquartile range (IQR): 0.59-2.79) was lower than in non-users (1.62 mg/L, IQR: 0.79-3.35), which after adjustment was estimated to be a 28% lower level. We observed an inverse association between duration of statin use and CRP levels. Elevated levels of IgE (>100 IU/mL) were more prevalent in statin users compared to non-users. A trend towards increased levels of IgE antibodies in statin users was observed, whereas no associations were found between statin use and levels of neopterin or the presence of autoantibodies. In this general population sub-sample, we observed an anti-inflammatory effect of statin use and a trend towards an increase of IgE levels, an surrogate marker for Th (helper) 2 responses without a decrease in neopterin levels, a surrogate marker for Th1 response and/or self-tolerance. We postulate that the observed decreased inflammatory response during statin therapy may be important but is insufficient to induce loss of self-tolerance.

Beyond aspirin-cancer prevention with statins, metformin and bisphosphonates

Cancer risk reduction using pharmacological means is an attractive modern preventive approach that supplements the classical behavioural prevention recommendations. Medications that are commonly used by large populations to treat a variety of common, non-cancer-related, medical situations are an attractive candidate pool. This Review discusses three pharmacological agents with the most evidence for their potential as cancer chemopreventive agents: anti-hypercholesterolaemia medications (statins), an antidiabetic agent (metformin) and antiosteoporosis drugs (bisphosphonates). Data are accumulating to support a significant negative association of certain statins with cancer occurrence or survival in several major tumour sites (mostly gastrointestinal tumours and breast cancer), with an augmented combined effect with aspirin or other non-steroidal anti-inflammatory drugs. Metformin, but not other hypoglycaemic drugs, also seems to have some antitumour growth activity, but the amount of evidence in human studies, mainly in breast cancer, is still limited. Experimental and observational data have identified bisphosphonates as a pharmacological group that could have significant impact on incidence and mortality of more than one subsite of malignancy. At the current level of evidence these potential chemopreventive drugs should be considered in high-risk situations or using the personalized approach of maximizing individual benefits and minimizing the potential for adverse effects with the aid of pharmacogenetic indicators.

Frequency of development of connective tissue disease in statin-users versus nonusers

Statins have pleiotropic properties that may affect the development of connective tissue diseases (CTD). The objective of this study was to compare the risk of CTD diagnoses in statin users and nonusers. This study was a propensity score-matched analysis of adult patients (30 to 85 years old) in the San Antonio military medical community. The study was divided into baseline (October 1, 2003 to September 30, 2005), and follow-up (October 1, 2005 to March 5, 2010) periods. Statin users received a statin prescription during fiscal year 2005. Nonusers did not receive a statin at any time during the study. The outcome measure was the occurrence of 3 diagnosis codes of the International Classification of Diseases, 9th Revision, Clinical Modification consistent with CTD. We described co-morbidities during the baseline period using the Charlson Comorbidity Index. We created a propensity score based on 41 variables. We then matched statin users and nonusers 1:1, using a caliper of 0.001. Of 46,488 patients who met study criteria (13,640 statin users and 32,848 nonusers), we matched 6,956 pairs of statin users and nonusers. Matched groups were similar in terms of patient age, gender, incidence of co-morbidities, total Charlson Comorbidity Index, health care use, and medication use. The odds ratio for CTD was lower in statin users than nonusers (odds ratio: 0.80; 95% confidence interval: 0.64 to 0.99; p = 0.05). Secondary analysis and sensitivity analysis confirmed these results. In conclusion, statin use was associated with a lower risk of CTD.

Statins and Breast Cancer: Future Directions in Chemoprevention

Given the high incidence, morbidity and mortality associated with breast cancer, developing effective chemopreventive strategies is crucial. Clinicians must carefully identify both populations at risk who would benefit from chemoprevention, and interventions that are effective and safe. Tamoxifen and raloxifene, the two agents approved for breast cancer chemoprevention, and third generation aromatase inhibitors reduce only the incidence of hormone receptor-positive tumors. 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMG-CoAR) inhibitors, or statins, are well tolerated and approved for prevention of cardiovascular disease. In preclinical breast cancer models statins carry potent anti-neoplastic activity. Results from epidemiological and clinical studies, however, are conflicting and have not identified a strong relationship between statin use and reduced breast cancer incidence. These studies have several limitations and were not designed to detect modest effects in high-risk populations. Additional focused epidemiological and translational studies in high-risk populations are needed to justify and guide definitive large prospective trials.

Long-term statin use and risk of ductal and lobular breast cancer among women 55 to 74 years of age

BACKGROUND

Mechanistic studies largely support the chemopreventive potential of statins. However, results of epidemiologic studies investigating statin use and breast cancer risk have been inconsistent and lacked the ability to evaluate long-term statin use.

METHODS

We used data from a population-based case-control study of breast cancer conducted in the Seattle-Puget Sound region to investigate the relationship between long-term statin use and breast cancer risk. Nine hundred sixteen invasive ductal carcinoma (IDC) and 1,068 invasive lobular carcinoma (ILC) cases in patients 55 to 74 years of age diagnosed between 2000 and 2008 were compared with 902 control women. All participants were interviewed in-person and data on hypercholesterolemia and all episodes of lipid-lowering medication use were collected through a structured questionnaire. We assessed the relationship between statin use and IDC and ILC risk using polytomous logistic regression.

RESULTS

Current users of statins for 10 years or longer had a 1.83-fold increased risk of IDC [95% confidence interval (CI): 1.14-2.93] and a 1.97-fold increased risk of ILC (95% CI: 1.25-3.12) compared with never users of statins. Among women diagnosed with hypercholesterolemia, current users of statins for 10 years or longer had more than double the risk of both IDC (OR: 2.04, 95% CI: 1.17-3.57) and ILC (OR: 2.43, 95% CI: 1.40-4.21) compared with never users.

CONCLUSION

In this contemporary population-based case-control study, long-term use of statins was associated with increased risks of both IDC and ILC.

IMPACT

Additional studies with similarly high frequencies of statin use for various durations are needed to confirm this novel finding.

Statins and the risk of lung cancer: a meta-analysis

PURPOSE

Several epidemiologic studies have evaluated the association between statins and lung cancer risk, whereas randomized controlled trials (RCTs) on cardiovascular outcomes provide relevant data as a secondary end point. We conducted a meta-analysis of all relevant studies to examine this association.

METHODS

A systematic literature search up to March 2012 was performed in PubMed database. Study-specific risk estimates were pooled using a random-effects model.

RESULTS

Nineteen studies (5 RCTs and 14 observational studies) involving 38,013 lung cancer cases contributed to the analysis. They were grouped on the basis of study design, and separate meta-analyses were conducted. There was no evidence of an association between statin use and risk of lung cancer either among RCTs (relative risk [RR] 0.91, 95% confidence interval [CI] 0.76-1.09), among cohort studies (RR 0.94, 95% CI 0.82-1.07), or among case-control studies (RR 0.82, 95% CI 0.57-1.16). Low evidence of publication bias was found. However, statistically significant heterogeneity was found among cohort studies and among case-control studies. After excluding the studies contributing most to the heterogeneity, summary estimates were essentially unchanged.

CONCLUSION

The results of our meta-analysis suggest that there is no association between statin use and the risk of lung cancer.

Observational data for comparative effectiveness research: an emulation of randomised trials of statins and primary prevention of coronary heart disease

This article reviews methods for comparative effectiveness research using observational data. The basic idea is using an observational study to emulate a hypothetical randomised trial by comparing initiators versus non-initiators of treatment. After adjustment for measured baseline confounders, one can then conduct the observational analogue of an intention-to-treat analysis. We also explain two approaches to conduct the analogues of per-protocol and as-treated analyses after further adjusting for measured time-varying confounding and selection bias using inverse-probability weighting. As an example, we implemented these methods to estimate the effect of statins for primary prevention of coronary heart disease (CHD) using data from electronic medical records in the UK. Despite strong confounding by indication, our approach detected a potential benefit of statin therapy. The analogue of the intention-to-treat hazard ratio (HR) of CHD was 0.89 (0.73, 1.09) for statin initiators versus non-initiators. The HR of CHD was 0.84 (0.54, 1.30) in the per-protocol analysis and 0.79 (0.41, 1.41) in the as-treated analysis for 2 years of use versus no use. In contrast, a conventional comparison of current users versus never users of statin therapy resulted in a HR of 1.31 (1.04, 1.66). We provide a flexible and annotated SAS program to implement the proposed analyses.

Statins for the primary prevention of cardiovascular disease

BACKGROUND

Reducing high blood cholesterol, a risk factor for cardiovascular disease (CVD) events in people with and without a past history of CVD is an important goal of pharmacotherapy. Statins are the first-choice agents. Previous reviews of the effects of statins have highlighted their benefits in people with CVD. The case for primary prevention was uncertain when the last version of this review was published (2011) and in light of new data an update of this review is required.

OBJECTIVES

To assess the effects, both harms and benefits, of statins in people with no history of CVD.

SEARCH METHODS

To avoid duplication of effort, we checked reference lists of previous systematic reviews. The searches conducted in 2007 were updated in January 2012. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2022, Issue 4), MEDLINE OVID (1950 to December Week 4 2011) and EMBASE OVID (1980 to 2012 Week 1).There were no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials of statins versus placebo or usual care control with minimum treatment duration of one year and follow-up of six months, in adults with no restrictions on total, low density lipoprotein (LDL) or high density lipoprotein (HDL) cholesterol levels, and where 10% or less had a history of CVD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion and extracted data. Outcomes included all-cause mortality, fatal and non-fatal CHD, CVD and stroke events, combined endpoints (fatal and non-fatal CHD, CVD and stroke events), revascularisation, change in total and LDL cholesterol concentrations, adverse events, quality of life and costs. Odds ratios (OR) and risk ratios (RR) were calculated for dichotomous data, and for continuous data, pooled mean differences (MD) (with 95% confidence intervals (CI)) were calculated. We contacted trial authors to obtain missing data.

MAIN RESULTS

The latest search found four new trials and updated follow-up data on three trials included in the original review. Eighteen randomised control trials (19 trial arms; 56,934 participants) were included. Fourteen trials recruited patients with specific conditions (raised lipids, diabetes, hypertension, microalbuminuria). All-cause mortality was reduced by statins (OR 0.86, 95% CI 0.79 to 0.94); as was combined fatal and non-fatal CVD RR 0.75 (95% CI 0.70 to 0.81), combined fatal and non-fatal CHD events RR 0.73 (95% CI 0.67 to 0.80) and combined fatal and non-fatal stroke (RR 0.78, 95% CI 0.68 to 0.89). Reduction of revascularisation rates (RR 0.62, 95% CI 0.54 to 0.72) was also seen. Total cholesterol and LDL cholesterol were reduced in all trials but there was evidence of heterogeneity of effects. There was no evidence of any serious harm caused by statin prescription. Evidence available to date showed that primary prevention with statins is likely to be cost-effective and may improve patient quality of life. Recent findings from the Cholesterol Treatment Trialists study using individual patient data meta-analysis indicate that these benefits are similar in people at lower (< 1% per year) risk of a major cardiovascular event.

AUTHORS' CONCLUSIONS

Reductions in all-cause mortality, major vascular events and revascularisations were found with no excess of adverse events among people without evidence of CVD treated with statins.

The role of statins in prevention and treatment of community acquired pneumonia: a systematic review and meta-analysis

BACKGROUND

Emerging epidemiological evidence suggests that statins may reduce the risk of community-acquired pneumonia (CAP) and its complications.

PURPOSE

Performed a systematic review to address the role of statins in the prevention or treatment of CAP.

DATA SOURCE

Ovid MEDLINE, Cochrane, EMBASE, ISI Web of Science, and Scopus from inception through December 2011 were searched for randomized clinical trials, cohort and case-control studies.

STUDY SELECTION

Two authors independently reviewed studies that examined the role of statins in CAP.

DATA EXTRACTION

Data about study characteristics, adjusted effect-estimates and quality characteristics was extracted.

DATA SYNTHESIS

Eighteen studies corresponding to 21 effect-estimates (eight and 13 of which addressed the preventive and therapeutic roles of statins, respectively) were included. All studies were of good methodological quality. Random-effects meta-analyses of adjusted effect-estimates were used. Statins were associated with a lower risk of CAP, 0.84 (95% CI, 0.74-0.95), I(2) = 90.5% and a lower short-term mortality in patients with CAP, 0.68 (95% CI, 0.59-0.78), I(2) = 75.7%. Meta-regression did not identify sources of heterogeneity. A funnel plot suggested publication bias in the treatment group, which was adjusted by a novel regression method with a resultant effect-estimate of 0.85 (95% CI, 0.77-0.93). Sensitivity analyses using the rule-out approach showed that it is unlikely that the results were due to an unmeasured confounder.

CONCLUSIONS

Our meta-analysis reveals a beneficial role of statins for the risk of development and mortality associated with CAP. However, the results constitute very low quality evidence as per the GRADE framework due to observational study design, heterogeneity and publication bias.

From medical records to clinical science

Medical records contain an abundance of information, very little of which is extracted and put to clinical use. Increasing the flow of information from medical records to clinical practice requires methods of analysis that are appropriate for large nonintervention studies. The purpose of this article is to explain in nontechnical language what these methods are, how they differ from conventional statistical analyses, and why the latter are generally inappropriate. This is important because of the current volume of nonintervention study analyses that either use incorrect methods or misuse correct methods. A set of guidelines is suggested for use in nonintervention clinical research.

Effect of pravastatin and fosinopril on recurrent urinary tract infections

OBJECTIVES

Recurrent urinary tract infections (UTIs) are a problem affecting both women and men. Animal experiments and in vitro studies indicate that statins might prevent recurrent UTIs. We assessed the effects of pravastatin on UTI antibiotic prescribing among adults.

METHODS

A post hoc analysis was conducted with data from PREVEND IT, a trial among participants randomized to receive pravastatin, fosinopril or placebo in a 2 × 2 factorial design over 4 years. Trial data were linked to the pharmacy prescription database IADB.nl. The primary outcome was the number of prescriptions with a nitrofuran derivate, a sulphonamide or trimethoprim as a proxy for UTI antibiotic prescribing. Generalized estimating equations were used to estimate the effect on the number of UTI antibiotic prescriptions. Cox regression was used to determine the effect on first and second (recurrent) UTI antibiotic prescriptions.

RESULTS

Of the 864 trial participants, 655 were eligible for analysis. During an average follow-up of 3.8 years, 112 (17%) participants received at least one UTI antibiotic prescription. Intention-to-treat analyses showed that pravastatin was associated with a reduced total number of UTI antibiotic prescriptions (relative risk, 0.43; 95% CI, 0.21-0.88) and occurrence of second UTI antibiotic prescriptions [hazard ratio (HR), 0.25; 95% CI, 0.08-0.77]. No significant effect on occurrence of first UTI antibiotic prescriptions was found (HR, 0.83; 95% CI, 0.57-1.20). Fosinopril was associated with an increased occurrence of first UTI antibiotic prescriptions (HR, 1.82; 95% CI, 1.16-2.88). Combination therapy with fosinopril and pravastatin did not significantly influence the number of UTI antibiotic prescriptions.

CONCLUSIONS

This study suggests that pravastatin can reduce the occurrence of recurrent UTIs. Larger studies among patients with recurrent UTIs are warranted.

Statins for the prevention of venous thromboembolism? a narrative review

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, is a substantial public health problem. The majority of VTE events are associated with transient periods of heightened risk, such as prolonged hospitalization, undergoing major surgery, experiencing trauma or lower extremity immobility, use of oral contraceptives, or having active cancer. Although pharmacologic thromboprophylaxis agents (eg, unfractionated heparin, low-molecular-weight heparins, warfarin, and novel oral anticoagulants) are effective, they remain underused, with concerns about increased bleeding risk often cited as a reason. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (ie, statins), although used primarily for lipid lowering and arterial thrombosis risk reduction, have pleiotrophic effects that affect coagulation and inflammation, and do not increase bleeding risk. There is emerging evidence to suggest that through these pleiotrophic effects, statins may be effective in reducing the incidence of VTE. This article summarizes the literature with regard to statins' effect on VTE and suggests that additional investigations are needed to assess a potential adjunctive role for primary VTE thromboprophylaxis.

Pharmacoepidemiology

Current concerns over the safety of medicines once they have been marketed mean that pharmacoepidemiology is of increasing importance. There are three main areas in which further research is needed. 1 To improve the methods used to make causal inference of effects of medicines and to raise the quality of the reporting and critical appraisal tools, so that the strengths and weaknesses of the new methods can be judged. 2 To apply the methods in areas where randomized trials cannot easily be done, such as in pregnancy. 3 To use electronic health records as fully as possible, using linkage between different databases, ensuring the data are of as high quality as possible. Public health and public perceptions mean that much of pharmacoepidemiology must be done using non-industry funding sources.

Statin use and risk of prostate cancer: a meta-analysis of observational studies

BACKGROUND

Emerging evidence suggests that statins may decrease the risk of cancers. However, available evidence on prostate cancer (PCa) is conflicting. We therefore examined the association between statin use and risk of PCa by conducting a detailed meta-analysis of all observational studies published regarding this subject.

METHODS

Literature search in PubMed database was undertaken through February 2012 looking for observational studies evaluating the association between statin use and risk of PCa. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using random-effects model (DerSimonian and Laird method). Subgroup analyses, sensitivity analysis and cumulative meta-analysis were also performed.

RESULTS

A total of 27 (15 cohort and 12 case-control) studies contributed to the analysis. There was heterogeneity among the studies but no publication bias. Statin use significantly reduced the risk of both total PCa by 7% (RR 0.93, 95% CI 0.87-0.99, p = 0.03) and clinically important advanced PCa by 20% (RR 0.80, 95% CI 0.70-0.90, p<0.001). Long-term statin use did not significantly affect the risk of total PCa (RR 0.94, 95% CI 0.84-1.05, p = 0.31). Stratification by study design did not substantially influence the RR. Furthermore, sensitivity analysis confirmed the stability of results. Cumulative meta-analysis showed a change in trend of reporting risk from positive to negative in statin users between 1993 and 2011.

CONCLUSIONS

Our meta-analysis provides evidence supporting the hypothesis that statins reduce the risk of both total PCa and clinically important advanced PCa. Further research is needed to confirm these findings and to identify the underlying biological mechanisms.

Statin use and risk of breast cancer: a meta-analysis of observational studies

Emerging evidence suggests that statins' may decrease the risk of cancers. However, available evidence on breast cancer is conflicting. We, therefore, examined the association between statin use and risk of breast cancer by conducting a detailed meta-analysis of all observational studies published regarding this subject. PubMed database and bibliographies of retrieved articles were searched for epidemiological studies published up to January 2012, investigating the relationship between statin use and breast cancer. Before meta-analysis, the studies were evaluated for publication bias and heterogeneity. Combined relative risk (RR) and 95 % confidence interval (CI) were calculated using a random-effects model (DerSimonian and Laird method). Subgroup analyses, sensitivity analysis, and cumulative meta-analysis were also performed. A total of 24 (13 cohort and 11 case-control) studies involving more than 2.4 million participants, including 76,759 breast cancer cases contributed to this analysis. We found no evidence of publication bias and evidence of heterogeneity among the studies. Statin use and long-term statin use did not significantly affect breast cancer risk (RR = 0.99, 95 % CI = 0.94, 1.04 and RR = 1.03, 95 % CI = 0.96, 1.11, respectively). When the analysis was stratified into subgroups, there was no evidence that study design substantially influenced the effect estimate. Sensitivity analysis confirmed the stability of our results. Cumulative meta-analysis showed a change in trend of reporting risk of breast cancer from positive to negative in statin users between 1993 and 2011. Our meta-analysis findings do not support the hypothesis that statins' have a protective effect against breast cancer. More randomized clinical trials and observational studies are needed to confirm this association with underlying biological mechanisms in the future.

Comparison of the effect on long-term outcomes in patients with thoracic aortic aneurysms of taking versus not taking a statin drug

The potential of medical therapy to influence the courses and outcomes of patients with thoracic aortic aneurysms is not known. The aim of this study was to determine whether statin intake is associated with improved long-term outcomes in these patients. A total of 649 patients with thoracic aortic aneurysms were studied, of whom 147 were taking statins at their first presentation and 502 were not. After a median follow-up period of 3.6 years, 30 patients (20%) taking statins had died, compared with 167 patients (33%) not taking statins (hazard ratio 0.68, 95% confidence interval 0.46 to 1, p = 0.049); 87 patients (59%) taking statins reached the composite end point of death, rupture, dissection, or repair compared with 378 patients (75%) not taking statins (hazard ratio 0.72, 95% confidence interval 0.57 to 0.91, p = 0.006). After adjustments for co-morbidities, the association between statin therapy and the composite end point was driven mainly by a reduction in aneurysm repairs (hazard ratio 0.57 95% confidence interval 0.4 to 0.83, p = 0.003). On Kaplan-Meier analysis, the survival rate of patients taking statins was significantly better (p = 0.047). In conclusion, the intake of stains was associated with an improvement in long-term outcomes in this cohort of patients with thoracic aortic aneurysms. This was driven mainly by a reduction in aneurysm repairs.

Sources of tissue factor that contribute to thrombosis after rupture of an atherosclerotic plaque

Hyperlipidemia leads to the formation of oxidized LDL (oxLDL), vessel dysfunction, atherosclerotic disease, and ultimately to plaque rupture and thrombosis. OxLDL induces tissue factor (TF) expression in various cell types, including monocytes and macrophages. High levels of TF are present in atherosclerotic plaques and this represents that major source of TF that triggers thrombosis after plaque rupture. In addition, increased levels of "circulating TF" are observed in hyperlipidemic animals and patients. This is due to induced TF expression in monocytes and release of monocyte-derived, TF(+) microparticles, which represents a minor source of TF that likely contributes to thrombosis after plaques rupture. This review will summarize the connections between hyperlipidemia and TF expression within atherosclerotic plaques and circulating monocytes, as well as its inhibition by statins.

Statins for age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a progressive late onset disorder of the macula affecting central vision. Age-related macular degeneration is the leading cause of blindness in people over 65 years in industrialized countries (Congdon 2003). Recent epidemiologic, genetic and pathological evidence has shown AMD shares a number of risk factors with atherosclerosis, leading to the hypothesis that statins may exert protective effects in AMD.

OBJECTIVES

To examine the effectiveness of statins compared with other treatments, no treatment, or placebo in delaying the onset and/or progression of AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 9), MEDLINE (January 1950 to September 2011), EMBASE (January 1980 to September 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to September 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 16 September 2011.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared statins with other treatments, no treatment, or placebo in participants who were either susceptible to or diagnosed as having early stages of AMD.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated the search results against the selection criteria. Two Italian speaking colleagues extracted data. One author entered data. We did not perform a meta-analysis because only one completed RCT was identified.

MAIN RESULTS

Two studies met the selection criteria. One trial reported insufficient details to assess the risk of bias; the other trial is ongoing.Of the completed trial, the analyses of 30 participants did not show a statistically significant difference between the simvastatin and the placebo arm in visual acuity at three months of treatment (decimal visual acuity 0.21± 0.56 in simvastatin and 0.19± 0.40 in placebo arm) or 45 days after the completion of treatment (decimal visual acuity 0.20± 0.50 in simvastatin and 0.19± 0.48 in placebo arm). The lens and retina status were unchanged during and after the treatment period for both groups.Of the ongoing trial, the preliminary analyses of 42 participants who completed 12 months follow-up did not show a statistically significant difference between the simvastatin and the placebo arm in visual acuity, drusen score or visual function (effect estimates and confidence intervals were not available). We contacted the investigators and will update the review as data become available.

AUTHORS' CONCLUSIONS

Evidence from currently available RCTs was insufficient to conclude that statins have any role in preventing or delaying the onset or progression of AMD.

Prevention of VTE in nonsurgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline addressed VTE prevention in hospitalized medical patients, outpatients with cancer, the chronically immobilized, long-distance travelers, and those with asymptomatic thrombophilia.

METHODS

This guideline follows methods described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

For acutely ill hospitalized medical patients at increased risk of thrombosis, we recommend anticoagulant thromboprophylaxis with low-molecular-weight heparin (LMWH), low-dose unfractionated heparin (LDUH) bid, LDUH tid, or fondaparinux (Grade 1B) and suggest against extending the duration of thromboprophylaxis beyond the period of patient immobilization or acute hospital stay (Grade 2B). For acutely ill hospitalized medical patients at low risk of thrombosis, we recommend against the use of pharmacologic prophylaxis or mechanical prophylaxis (Grade 1B). For acutely ill hospitalized medical patients at increased risk of thrombosis who are bleeding or are at high risk for major bleeding, we suggest mechanical thromboprophylaxis with graduated compression stockings (GCS) (Grade 2C) or intermittent pneumatic compression (IPC) (Grade 2C). For critically ill patients, we suggest using LMWH or LDUH thromboprophylaxis (Grade 2C). For critically ill patients who are bleeding or are at high risk for major bleeding, we suggest mechanical thromboprophylaxis with GCS and/or IPC at least until the bleeding risk decreases (Grade 2C). In outpatients with cancer who have no additional risk factors for VTE we suggest against routine prophylaxis with LMWH or LDUH (Grade 2B) and recommend against the prophylactic use of vitamin K antagonists (Grade 1B).

CONCLUSIONS

Decisions regarding prophylaxis in nonsurgical patients should be made after consideration of risk factors for both thrombosis and bleeding, clinical context, and patients' values and preferences.