Statin use and risk of cataract: A nested case-control study within a healthcare database

Prevalence of cataract and its contributing factors in Iranian elderly population: the Gilan eye study

PURPOSE

To report the prevalence and the associated factors leading to cataract among the Iranian population living in Gilan Province, Iran.

METHODS

This population-based cross-sectional study was performed from June to November 2014 on 2,975 residents aged ≥ 50 years old living in urban and rural regions of the Gilan Province in Iran. A representative sample of residents in the province was recruited into the study through door-to-door visiting, and baseline data were collected by questionnaire. All participants were referred to the medical center for comprehensive ophthalmic examination, laboratory tests, and blood pressure measurement.

RESULTS

Among the population, 2,588 (86.99%) subjects were eligible to be included in this study, categorized either into the cataract or the non-cataract group. The mean age of participants was 62.59 ± 8.92 years, and 57.5% were female. Higher prevalence of cataract was found in individuals of older ages (odds ratio (OR) = 1.13; 95% confidence interval (CI) = 1.10 to 1.16; P < 0.001) and a history of previous ocular surgery (OR = 5.78; 95% CI = 2.28 to 14.63; P < 0.001). At the same time, a lower prevalence of cataract was seen in patients exposed to sunlight for more than 4 h per day (OR = 0.49; 95% CI = 0.32 to 0.73; P = 0.001).

CONCLUSION

Cataract affects 50.50% of the study population, especially those over 80. The mildest form of cataract, grade zero, is the most common. Surgery for cataract has good outcomes. The risk of cataract is higher for those older or who have had eye surgeries. People not affected by cataract tend to be exposed to more sunlight.

Possible link between statin and iron deficiency anemia: A South Korean nationwide population-based cohort study

An extensive evaluation of disease occurrence after statin use based on a "hypothesis-free" approach remains scarce. To examine the effect of statin use on the potential risk of developing diseases, a propensity score-matched cohort study was executed using data from the National Sample Cohort in South Korea. A total of 7847 statin users and 39,235 nonstatin users were included in the final analysis. The period of statin use was defined as our main time-dependent exposure and was divided into three periods: current, recent, and past. The main outcomes were defined as new-onset diseases with ≥100 events based on the International Statistical Classification of Diseases, 10th Revision. We calculated the adjusted hazard ratios and 95% confidence intervals (CIs) using Cox regression. We found that statin use significantly increased the risk of developing iron deficiency anemia up to 5.04 times (95% CI, 2.11 to 12.03). Therefore, the iron levels of patients using statins should be monitored carefully.

Pantothenate Kinase 4 Governs Lens Epithelial Fibrosis by Negatively Regulating Pyruvate Kinase M2-Related Glycolysis

Lens fibrosis is one of the leading causes of cataract in the elderly population. The primary energy substrate of the lens is glucose from the aqueous humor, and the transparency of mature lens epithelial cells (LECs) is dependent on glycolysis for ATP. Therefore, the deconstruction of reprogramming of glycolytic metabolism can contribute to further understanding of LEC epithelial-mesenchymal transition (EMT). In the present study, we found a novel pantothenate kinase 4 (PANK4)-related glycolytic mechanism that regulates LEC EMT. The PANK4 level was correlated with aging in cataract patients and mice. Loss of function of PANK4 significantly contributed to alleviating LEC EMT by upregulating pyruvate kinase M2 isozyme (PKM2), which was phosphorylated at Y105, thus switching oxidative phosphorylation to glycolysis. However, PKM2 regulation did not affect PANK4, demonstrating the downstream role of PKM2. Inhibition of PKM2 in Pank4-/- mice caused lens fibrosis, which supports the finding that the PANK4-PKM2 axis is required for LEC EMT. Glycolytic metabolism-governed hypoxia inducible factor (HIF) signaling is involved in PANK4-PKM2-related downstream signaling. However, HIF-1α elevation was independent of PKM2 (S37) but PKM2 (Y105) when PANK4 was deleted, which demonstrated that PKM2 and HIF-1α were not involved in a classic positive feedback loop. Collectively, these results indicate a PANK4-related glycolysis switch that may contribute to HIF-1 stabilization and PKM2 phosphorylation at Y105 and inhibit LEC EMT. The mechanism elucidation in our study may also shed light on fibrosis treatments for other organs.

Antihypertensive Use and the Risk of Cataract in Patients with Hypertension: A Nationwide Case-control Study

PURPOSE

This study aims to investigate the association between antihypertensive use and the risk of cataract in a matched case-control study.

METHODS

We analysed the Korean National Health Insurance Service-Health Screening Cohort database from 2002 to 2013. We defined 'cases' as patients prescribed antihypertensives and underwent their first eye cataract surgery between 2010 and 2013. 'Controls' were patients prescribed antihypertensives and no history of cataract surgery or diagnosis between 2002 and 2013. Four controls were matched to each case by several variables. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated for cataract risk using a conditional logistic regression model after adjustment.

RESULTS

The analyses comprised 12,166 cases and 48,664 controls. The adjusted ORs for cataracts were 1.18 (95% CI: 1.12-1.24) in thiazide diuretics, 1.12 (95% CI: 1.07-1.18) in beta-blockers, 0.94 (95% CI: 0.90-1.00) in calcium channel blockers, 1.22 (95% CI: 1.14-1.30) in angiotensin-converting enzyme (ACE) inhibitors, and 0.97 (95% CI: 0.91-1.03) in angiotensin II receptor blockers compared to 'non-use' of each antihypertensive.

CONCLUSION

In a nationwide case-control study, the use of thiazide diuretics, beta-blockers, or ACE inhibitors do not represent minimal clinical important difference in the risk of cataract and the use of calcium channel blockers or angiotensin II receptor blockers is not associated with an increased risk of cataracts compared to non-use of each antihypertensive. Given the benefits of treating hypertension, such as the reduction in further complications, we suggest there is no need to change current clinical practice for antihypertensives.

Effect of hydrophilic and lipophilic statins on early onset cataract: A nationwide case-control study

BACKGROUND

Statin is biologically plausible in cataract development, but inconclusive associations between statin and cataract are presented in human studies. Given most early onset cataract (EOC) occurs in regions with high cholesterol composition, we therefore aimed to assess the association between statin and EOC.

METHODS

A population based case-control study was performed using the Taiwan National Health Insurance Research Database (NHIRD). The case involved patients aged 20-55 years with EOC. Controls were 1:1 matched by age, gender, year of index date, and propensity score estimated from comorbidities and comedications. Statin exposure, including intensity, properties and cumulative exposure one year before the index date were tracked. The odds ratios (ORs) of EOC associated with statin were estimated by conditional logistic regression.

RESULTS

A total of 4213 cases and 4213 controls were included. Statins were associated with EOC (OR = 3.257, 95% CI 2.519-4.211). The ORs of cataract was positively associated with cumulative exposure. Subgroup analysis indicated that the ORs of cataract were significant both in lipophilic (OR = 3.485, 95% CI 2.606-4.659) and hydrophilic (OR = 3.241, 95% CI 1.975-5.321) statin users.

CONCLUSIONS

Statins were associated with an increased risk of cataract in young populations.

Impact of medication nonadherence on stroke recurrence and mortality in patients after first-ever ischemic stroke: Insights from registry data in Singapore

PURPOSE

This retrospective cohort study aims to examine adherence to secondary stroke preventive medications and their association with risk of stroke recurrence and mortality in patients after first-ever ischemic stroke.

METHODS

Using data from the National Healthcare Group and Singapore Stroke Registry, patients with first-ever ischemic stroke between 2010 and 2014 were included, and categorized based on antithrombotic or statin adherence using the proportion of days covered: high (≥75%), intermediate (50%-74%), low (25%-49%), and very low (<25%). The primary outcome was first recurrent ischemic stroke within a year after hospital discharge, while the secondary composite outcomes were (a) stroke recurrence and all-cause mortality and (b) stroke recurrence and cardiovascular mortality. The Cox proportional hazard model was used to examine the association between medication adherence and outcomes. Adjusted hazard ratios (aHRs) and the corresponding 95% confidence intervals (CIs) were reported.

RESULTS

Among ischemic stroke patients prescribed with antithrombotics (n = 1139) or statins (n = 1160) at hospital discharge, about one-third were highly adherent to their medications. Patients with lower medication adherence tended to be younger, were admitted to private ward classes, and were without hypertension. Compared with the patients with high medication adherence, the risk of stroke recurrence was higher in patients with very low antithrombotic (aHR = 4.65; 95% CI: 1.45-14.89) or statin (aHR = 3.44; 95% CI: 0.93-12.74) adherence. Similar findings were observed for the secondary outcomes.

CONCLUSIONS

Poor adherence to antithrombotic and statin treatment increases the risk of recurrent stroke and mortality in patients after first-ever ischemic stroke. Further measures are needed to improve medication adherence among stroke survivors.

Statins and risk of cataracts: A systematic review and meta-analysis of observational studies

INTRODUCTION

Two previous meta-analyses evaluated the risk of cataracts associated with statins, but did not include relevant studies suggesting a cataractogenic effect.

AIMS

The aim of this systematic review and meta-analysis of observational studies is to evaluate such association considering the latest published evidence.

METHODS

A literature search was conducted to identify observational, comparative studies evaluating the risk of developing cataracts in patients treated with statins. A meta-analysis was performed to estimate odds ratios (ORs). Results were stratified according to the following studies' subgroups: design, methodological quality, method of diagnosis of cataract, patients' age, and median follow-up. Meta-regressions evaluated the influence of the following risk factors: smoking, hypertension, corticosteroids, selective serotonin reuptake inhibitors (SSRI), diabetes mellitus, and cardiovascular disease.

RESULTS

Twenty-one studies were included. Treatment with statins was associated with an increased risk of cataracts [OR: 1.11 (95% CI: 1.02-1.21); P = 0.017; I²  = 97.5%]. This risk remained statistically significant among case-controls, good methodological quality studies, studies with length of follow-up ≥5 years and those which outcome was cataract surgery. Between-studies heterogeneity was high among all risk estimates. Meta-regressions identified an inverse relationship between the risk of cataracts and the proportion of diabetic patients in the studies.

CONCLUSIONS

The results point out an increased risk of cataract development with statins. However, since the magnitude of the effect is low and between-studies heterogeneity is high, the extent in which these results have impact on the benefit/risk ratio of statins is difficult to ascertain due to the uncertainty of the findings.

Adverse effects of statin therapy: perception vs. the evidence - focus on glucose homeostasis, cognitive, renal and hepatic function, haemorrhagic stroke and cataract

Aims

To objectively appraise evidence for possible adverse effects of long-term statin therapy on glucose homeostasis, cognitive, renal and hepatic function, and risk for haemorrhagic stroke or cataract.

Methods and results

A literature search covering 2000-2017 was performed. The Panel critically appraised the data and agreed by consensus on the categorization of reported adverse effects. Randomized controlled trials (RCTs) and genetic studies show that statin therapy is associated with a modest increase in the risk of new-onset diabetes mellitus (about one per thousand patient-years), generally defined by laboratory findings (glycated haemoglobin ≥6.5); this risk is significantly higher in the metabolic syndrome or prediabetes. Statin treatment does not adversely affect cognitive function, even at very low levels of low-density lipoprotein cholesterol and is not associated with clinically significant deterioration of renal function, or development of cataract. Transient increases in liver enzymes occur in 0.5-2% of patients taking statins but are not clinically relevant; idiosyncratic liver injury due to statins is very rare and causality difficult to prove. The evidence base does not support an increased risk of haemorrhagic stroke in individuals without cerebrovascular disease; a small increase in risk was suggested by the Stroke Prevention by Aggressive Reduction of Cholesterol Levels study in subjects with prior stroke but has not been confirmed in the substantive evidence base of RCTs, cohort studies and case-control studies.

Conclusion

Long-term statin treatment is remarkably safe with a low risk of clinically relevant adverse effects as defined above; statin-associated muscle symptoms were discussed in a previous Consensus Statement. Importantly, the established cardiovascular benefits of statin therapy far outweigh the risk of adverse effects.

Clinical and pathophysiological evidence supporting the safety of extremely low LDL levels-The zero-LDL hypothesis

While the impact of very low concentrations of low-density lipoprotein cholesterol (LDL-C) on cardiovascular prevention is very reassuring, it is intriguing to know what effect these extremely low LDL-C concentrations have on lipid homoeostasis. The evidence supporting the safety of extremely low LDL levels comes from genetic studies and clinical drug trials. Individuals with lifelong low LDL levels due to mutations in genes associated with increased LDL-LDL receptor (LDLR) activity reveal no safety issues. Patients achieving extremely low LDL levels in the IMPROVE-IT and FOURIER, and the PROFICIO and ODYSSEY programs seem not to have an increased prevalence of adverse effects. The main concern regarding extremely low LDL-C plasma concentrations is the adequacy of the supply of cholesterol, and other molecules, to peripheral tissues. However, LDL proteomic and kinetic studies reaffirm that LDL is the final product of endogenous lipoprotein metabolism. Four of 5 LDL particles are cleared through the LDL-LDLR pathway in the liver. Given that mammalian cells have no enzymatic systems to degrade cholesterol, the LDL-LDLR pathway is the main mechanism for removal of cholesterol from the body. Our focus, therefore, is to review, from a physiological perspective, why such extremely low LDL-C concentrations do not appear to be detrimental. We suggest that extremely low LDL-C levels due to increased LDLR activity may be a surrogate of adequate LDL-LDLR pathway function.