Mahyar Etminan's research while affiliated with University of British Columbia - Vancouver and other places

Publications (199)

Article
Competing events are events that preclude the occurrence of the primary outcome. Much has been written on mainly the statistics behind competing events analyses. However, many of these publications and tutorials have a strong statistical tone and might fall short in providing a practical guide to clinician researchers as to when to use a competing...
Article
Previous papers have mentioned that conditioning on a binary collider would introduce an association between its causes at least in one stratum. In this paper, we prove this statement and along with intuitions, formally examine the direction and magnitude of the associations between two risk factors of a binary collider using interaction contrasts....
Article
Importance: Recent case reports suggest use of topical prostaglandin analogues (PGAs) might increase the risk of spontaneous abortions in pregnant people who take these drugs for intraocular pressure control. However, because these reports are derived mainly from voluntary adverse drug reaction databases, they might be prone to reporting bias. Ob...
Article
Importance: A number of case reports and small epidemiologic studies have quantified the risk of ocular adverse events associated with the use of phosphodiesterase type 5 inhibitors (PDE5Is). However, results have been conflicting, and epidemiologic data on the risk of serous retinal detachment (SRD) and retinal vascular occlusion (RVO) are not av...
Article
Aims: Recent epidemiologic studies have examined the risk of maculopathy with pentosan polysulfate sodium (PPS), a drug indicated for the treatment of interstitial cystitis. However, results have been contradictory. Thus, we quantified the risk of maculopathy with PPS with a focus on risk with duration of use. Methods: We used a new user, retros...
Preprint
OBJECTIVE Taxane based chemotherapy agents such as docetaxel and paclitaxel are used for a wide range of cancers. Although much has been published on adverse events related to taxanes, data on ocular outcomes with these very important drugs is scant. We sought to quantify the risk of three ocular adverse events: 1) epiphora, 2) cystoid macular edem...
Article
Full-text available
Purpose Hydroxychloroquine (HCQ) is an important medication for patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and other rheumatic diseases. Although it is well-tolerated and cost-effective, the risk of HCQ retinal toxicity is of increasing concern. The aim of this study is to re-examine the HCQ retinal toxicity inciden...
Article
Full-text available
PurposePrevious studies have indicated an increased risk of gallbladder disease with hormonal contraceptives although with discordant results. The potential increased risk of gallbladder disease with hormonal contraceptives is concerning given that women are at increased risk of this disease. Thus, the aim of this study was to examine risk of surge...
Article
Background Context Current prognostic tools such as the Injury Severity Score (ISS) that predict mortality following trauma do not adequately consider the unique characteristics of traumatic spinal cord injury (tSCI). Purpose Our aim was to develop and validate a prognostic tool that can predict mortality following tSCI. Study Design Retrospectiv...
Article
To the Editor We read with interest the study by Blitzer et al¹ on the association between metformin and age-related macular degeneration (AMD). We would like to highlight 3 potential limitations of this study. First, individuals with AMD were matched with control participants on a 1:1 scheme by anemia, age, hypertension, geographic location, and c...
Article
Aims: We aimed to investigate the association between hormonal contraceptive (HC) use and the incidence of glaucoma in females of reproductive age with a focus on duration and type of HCs used. Methods: A retrospective cohort study with a case-control analysis (nested case-control) was undertaken using data from IQVIA's electronic medical record...
Article
Ophthalmic surgery requires a highly dexterous and precise surgical approach to work within the small confines of the eye, and the use of robotics offers numerous potential advantages to current surgical techniques. However, there is a lag in the development of a comprehensive training and credentialing system for robotic eye surgery, and certifica...
Article
Background: Hormonal contraceptives (HCs) are a known risk factor for dry eye disease (DED), yet the relationship between HCs use and DED in women of child-bearing age remains debatable. The aim of this study was to determine the association between HCs and DED in females of reproductive age. Methods: This was a retrospective cohort study using...
Article
Covariate adjustment is integral to the validity of observational studies assessing causal effects. It is common practice to adjust for as many variables as possible in observational studies in the hopes of reducing confounding by other variables. However, indiscriminate adjustment for variables using standard regression models may actually lead to...
Article
Full-text available
Background: In contemporary guidelines for the management of Chronic Obstructive Pulmonary Disease (COPD), the history of acute exacerbations plays an important role in the choice of long-term inhaled therapies. This study aimed at evaluating population-level trends of filled inhaled prescriptions over the time course of COPD and their relation to...
Article
Full-text available
Purpose: To examine whether there is a positive association between sexual dysfunction (SD) and different types of progestin-based contraceptives. Methods: Nested case-control study in women of child-bearing age (15-45 years) from the IQVIA® Ambulatory electronic medical record database from 2008 to 2018. Cases defined by diagnosis of sexual dys...
Article
Introduction The use of observational data to assess drug effectiveness and safety can provide relevant information, much of which may not be feasible to obtain through randomized clinical trials. Because observational studies provide critical drug safety and effectiveness information that influences drug policy and prescribing practices, transpare...
Article
Background Comparative safety data on the risk of pseudotumor cerebri syndrome (PTCS) with different hormonal contraceptives is absent. We sought to quantify the risk of PTCS with eight different types of hormonal contraceptives compared with oral levonorgestrel. Methods A retrospective cohort study with a case‐control analysis was used on 4,871,5...
Article
There have been concerns regarding the safety of non‐steroidal anti‐inflammatory drugs (NSAIDs) in patients with respiratory infections. However, to date the quality of the evidence has not been systematically assessed. The purpose of this systematic review was to evaluate the role of NSAIDs on pneumonia complications. OVID MEDLINE, EMBASE, Cochran...
Article
Causal directed acyclic graphs (cDAGs) have become popular tools for researchers to better examine biases related to causal questions. DAGs comprise a series of arrows connecting nodes that represent variables and in doing so can demonstrate the causal relation between different variables. cDAGs can provide researchers with a blueprint of the expos...
Article
To the Editor We read with great interest the study by Zven et al,¹ which examined whether exposure to antibiotics at infancy is associated with an increased risk of allergic diseases in childhood. Overall, the study showed an increased risk of allergic diseases with exposure to commonly prescribed antibiotics, with adjusted hazard ratios ranging f...
Article
Currently there is a race against time to identify prophylactic and therapeutic treatments against COVID‐19. Until these treatments are developed, tested and mass produced, it might be prudent to look into existing therapies that could be effective against this virus. Based on the available evidence we believe that tetracyclines may be effective ag...
Article
Introduction: Multiple studies have investigated the role of β2 -adrenoreceptor agonists on the risk of Parkinson's disease (PD). However, whether β2 -agonist use is associated with the risk of PD in patients with chronic obstructive pulmonary disease (COPD) has not been examined to date. Objectives: To examine the association between use of β2...
Article
Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are potentially life-threatening, immune-mediated adverse reactions characterized by widespread erythema, epidermal necrosis, and detachment of skin and mucosa. Efforts to grow and develop functional international collaborations and a multidisciplinary interactive network focusing on...
Article
Introduction Macrolides are widely used during pregnancy; however, their fetal safety remains uncertain. We performed a meta-analysis to assess the relation between prenatal exposure to macrolides and occurrence of congenital malformations. Methods We searched MEDLINE, EMBASE, and other databases until June 12, 2019. We assessed the quality of the...
Article
Optical coherence tomography angiography (OCTA) is a noninvasive method that enables visualization of blood flow within retinal vessels down to the size of capillaries by detecting motion contrast from moving blood cells. OCTA provides a fast and safe procedure to assess retinal microvasculature with higher contrast and resolution than conventional...
Article
Background Recent studies have linked fluoroquinolones (FQs) to cardiac adverse events, including aortic dissection and aneurysm. To date, whether FQs can increase the risk of aortic or mitral regurgitation has not been studied. Objectives This disproportionality analysis and case-control study examined whether FQs increase the risk of aortic and...
Article
Precis: Gabapentin and its derivatives have numerous indications and are commonly prescribed medications. In this article, we provide evidence of a link between gabapentinoid use and incidence of acute angle-closure glaucoma. Purpose: Gabapentinoids, such as gabapentin and pregabalin, are commonly prescribed classes of drugs in North America. We...
Article
Full-text available
Purpose: To quantify the risk of ocular adverse events with immune checkpoint inhibitors (ICIs) as reported to the Food and Drug Administration (FDA). Methods: Disproportionality analysis using data from U.S. FDA's Adverse Events Reporting System (FAERS) database 2003 to 2018. Data from pharmaceutical manufacturers, healthcare providers, consume...
Article
We thank the authors, Lai and Brown, for their interest in our study. Overall, we agree that there were unmeasured confounders, such as hormonal imbalances, that could not be controlled for as stated in our limitations. While numerous pharmacological agents have shown to be associated with gynecomastia (2), we did adjust for these drugs (ketoconazo...
Article
Full-text available
Introduction: Proton pump inhibitors (PPIs) are commonly prescribed for many gastrointestinal diseases. A number of case reports have linked PPIs to gynecomastia in men, but large epidemiologic studies are lacking. Objective: To quantify the risk of gynecomastia with PPIs in male patients. Methods: Using the PharMetrics Plus™ health claims dat...
Article
Background Osteoporosis is a multifactorial disease hallmarked by the interaction of genetic, nutritional and environmental factors. We aimed to assess the effect of alcohol consumption on the osteoporosis by undertaking a systematic review and meta-analysis. Methods We searched electronic databases including MEDLINE, Scopus, and Web of Science un...
Article
Full-text available
Objectives Diet and nutrition might play an important role in the aetiology of metabolic syndrome (MetS). Most studies that examine the effects of food intake on MetS have used conventional statistical analyses which usually investigate only a limited number of food items and are subject to sparse data bias. This study was undertaken with the goal...
Article
The Food and Drug Administration (FDA) has recently included a black box warning on fibromyalgia like symptoms with fluoroquinolones (FQs) but no large epidemiologic study is to date available. We undertook a case-control study using a random sample of 9,053,240 subjects obtained from the PharMetrics Plus health claims database in the United States...
Article
Importance: Tumor necrosis factor inhibitors (TNFi) are widely used in the treatment of a variety of autoimmune diseases. A number of case reports have linked TNFi to neurologic adverse events including peripheral neuropathy (PN) in patients with rheumatic diseases. Objectives: To quantify the risk of peripheral neuropathy with TNFi in patients...
Article
Full-text available
Purpose To examine the risk of developing Parkinson's Disease (PD) in patients who are newly diagnosed with neovascular age-related macular degeneration (nAMD). Methods This was a cohort study using the British Columbia (BC) Retinal Disease Database. Data from 2009 to 2013 was accessed. Rates of PD in patients prior to the diagnosis of nAMD were c...
Article
Objective: Previous studies suggested that glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may initially worsen and possibly increase the risk of diabetic retinopathy. However, data on this possible association remain limited. Thus, this population-based study aimed to determine whether use of GLP-1 RAs is associated with an increased risk o...
Article
Background Although antipsychotics are used to treat Tourette syndrome, there have been reports of paradoxical induction of tics by first- and second-generation antipsychotics. Objective The objective of this systematic review was to better characterize tics as the potential adverse effect of antipsychotics. Methods A literature search was perfor...
Article
The current body of evidence on the efficacy and safety of aflibercept for age‐related macular degeneration (AMD) is steadily growing as large clinical trials and observational studies are continually completed. Our aim was to analyse 1‐year visual acuity (VA) outcomes in response to aflibercept therapy and identify factors affecting treatment resp...
Article
Objective Case reports have suggested an increased risk of gynecomastia with HMG‐CoA reductase inhibitors (i.e. statins). A recent meta‐analysis also found that statins decrease circulating testosterone levels in men. We investigated whether statin use was associated with an increased risk of gynecomastia. Design Case control study. Patients A co...
Article
Background: Antidepressants are one of the most prescribed classes of medications. A number of case reports have linked these drugs to extrapyramidal symptoms (EPSs), but no large epidemiologic study to date has examined this association. We sought to quantify the association of EPSs with different antidepressants by undertaking a large pharmacoep...
Article
Background Lorcaserin and phentermine-topiramate are two drugs marketed for obesity that have shown moderate efficacy after one year of use. However, concerns over risks of serious cardiovascular harms including valvulopathy have been brought up for both drugs, prompting an epidemiologic investigation to quantify this adverse outcome using real-wor...
Article
Background: Fluoroquinolone (FQ) prescription rates have increased over the last 10 years despite recent warnings of serious adverse effects such as peripheral neuropathy and tendinopathy. Currently, there are no published data on the extent or appropriateness of FQ prescribing in children METHODS:: Drug prescription data from the PharMetrics Plus...
Article
In recent years, there has been an explosion of research articles using large population databases in clinical research; ophthalmology is no exception. In 2012, using the British Columbia Ministry of Health database, we published one of the first population-based pharmacoepidemiologic studies¹ that found an elevated risk of retinal detachment (RD)...
Article
Purpose: To determine the risk of developing anterior segment complications after receiving the live herpes zoster virus vaccine. Methods: This retrospective cohort study included a random sample of 9 million patients registered in a health-claim database in the United States between 2006 and 2016. Herpes zoster-related anterior segment diseases...
Article
Purpose: To determine the association of post-operative topical prostaglandin analog (PGA) or topical beta-blocker use and the incidence of pseudophakic cystoid macular edema (CME). Methods and patients: This was a nested case control study. All adult patients who underwent cataract surgery between January 1, 2006 and December 31, 2016 and who w...
Article
Background: Hormonal contraceptives (HC), one of the most prescribed classes of medication in women, have been linked with pseudotumor cerebri syndrome (PTCS). To date, no large epidemiologic study has examined this association.Methods: A case-control study using the IMS LifeLink Pharmetrics Plus database was conducted. Cases had an ICD-9-CM code f...
Article
Objective To assess effectiveness of intravitreous bevacizumab in a cohort of patients with neovascular age-related macular degeneration (nAMD) in British Columbia, Canada. Design Retrospective cohort study. Participants Patients with new-onset AMD who completed 1 year of bevacizumab treatment. Methods A cohort of 4507 patients with nAMD (5174 e...
Data
Regression coefficients for the joint frailty model. (DOCX)
Data
Results of the sensitivity analyses: Death defined as the first day of the month that death occurred. (DOCX)
Data
Results of the sensitivity analyses: Death defined as the last day of the month that death occurred. (DOCX)
Article
Full-text available
Background There is minimal evidence on the extent to which the occurrence of a severe acute exacerbation of COPD that results in hospitalization affects the subsequent disease course. Previous studies on this topic did not generate causally-interpretable estimates. Our aim was to use corrected methodology to update previously reported estimates of...
Data
Details of the joint frailty model. (DOCX)
Data
Results of the sensitivity analysis: Eight-year wash-in period. (DOCX)
Article
Purpose: The clinical efficacy of ranibizumab has been examined by a large number of prospective and retrospective studies to date. This meta-analysis was conducted to summarize the current body of evidence on visual acuity (VA) changes with use of ranibizumab in the treatment of neovascular age-related macular degeneration (wAMD). Methods: A li...
Article
Many exposures of epidemiological interest are time varying, and the values of potential confounders may change over time leading to time varying confounding. The aim of many longitudinal studies is to estimate the causal effect of a time varying exposure on an outcome that requires adjusting for time varying confounding. Time varying confounding a...
Article
Objective: Recently, there has been great interest in the use, abuse and over-prescribing of opioid analgesics for children. However, there is a paucity of evidence on patterns of prescribing of both narcotic and non-narcotic analgesics for children by dentists. Methods: We used a population-wide prescription drug database (PharmaNet) in British...
Article
Objective: To quantify the risk of secondary pseudotumor cerebri syndrome (PTCS) with fluoroquinolones. Methods: A case-control study of people 15-60 years of age from the LifeLink Database (QuintilesIMS Parsippany, NJ) was conducted. Cases had the first ICD-9-CM code for benign intracranial hypertension (BIH) as well as having received a proced...
Article
The aim of this study was to quantify the risk of hair loss with different antidepressants. A retrospective cohort study design using a large health claims database in the USA from 2006 to 2014 was utilized. A cohort of new user and mutually exclusive users of fluoxetine, fluvoxamine, sertraline, citalopram, escitalopram, paroxetine, duloxetine, ve...
Article
Fluoroquinolone (FQ) induced peripheral neuropathies and tendinopathies are well documented, but there are no epidemiologic studies on the risk of carpel tunnel syndrome (CTS). We conducted a case-control study of over 6 million patients. FQ use is associated with increased risk of CTS (RR = 1.34, 95% CI 1.31 - 1.37).
Article
Importance: Intravitreous injections of anti-vascular endothelial growth factor (VEGF) agents are associated with a sustained increase in intraocular pressure. This sustained elevated intraocular pressure could lead to higher rates of glaucoma surgery to lower this pressure. Objective: To determine the risk of glaucoma surgery following repeated...