Propensity Score Matching in Nonrandomized Studies: A Concept Simply Explained Using Antidepressant Treatment During Pregnancy as an Example

2019

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Depression and Eye Diseases Zheng et al 1 described a systematic review and meta-analysis of depression and depressive symptoms in patients with eye diseases. They identified 28 relevant studies (pooled N = 6,589) and estimated that the prevalence of depression or depressive symptoms was 25% (95% CI, 20%-30%) in the pooled sample. The highest prevalence was found in patients with xerophthalmia (29%). The prevalence was also high in patients with glaucoma (25%), age-related macular degeneration (24%), and cataract (23%). Patients with eye disease were at higher risk of depression or depressive symptoms than healthy controls (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.40-1.81). It is possible that the depression in patients with eye disease is a reaction to the ocular symptoms, and it is possible that the depression and eye disease occur coincidentally. It is also possible that depression and its correlates are a risk factor for at least some eye diseases. In this context, one possibility is that the antidepressant drugs used to treat depression increase the risk of cataract. Cataract Cataract is a disease of the eye that is characterized by impairment of vision resulting from the development of opacities in the lens. Cataract is the leading cause of blindness in low and middle income countries. The prevalence of cataract is about 4% in persons who are around 60 years of age and > 90% in those who are 80 years and older. Risk factors for cataract include older age, female sex, genetic vulnerabilities, lifestyle behaviors, medical comorbidities, and many others. 2 Psychotropic drugs, particularly antidepressant drugs, have recently been associated with cataract. This article critically examines the literature on the subject. Antidepressant Drugs and Cataract: Meta-Analysis Fu et al 3 described a systematic review and meta-analysis of studies that examined the development of cataract after antidepressant use. They searched electronic databases, reference lists, and other sources and identified 7 relevant case-control studies; 3 had been conducted in the United States, 2 in Canada, and 1 each in the United Kingdom and Taiwan. The pooled sample included 447,672 cases and 1,510,391 controls. Important findings from the meta-analysis 3 are presented in Table 1. In short, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and tricyclic antidepressants were each associated with a small but statistically significant increase in the risk of cataract. All 3 analyses were characterized by substantial heterogeneity; the authors did not examine the source of the heterogeneity. Among individual antidepressant drugs, the risk was significant for citalopram, fluoxetine, fluvoxamine, and venlafaxine but not for paroxetine, sertraline, escitalopram, duloxetine, and milnacipran; it is possible that many analyses were underpowered for the individual drugs. Visual inspection of the funnel plot suggested clear publication bias.

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Section: Antidepressants and Cataract: Suggestions For Future Researchmentioning

confidence: 99%

Antidepressants, Mood Stabilizers, Antipsychotics, and the Risk of Cataract

2019

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“…The problem of confounding in observational studies in pregnancy has been discussed in detail in earlier articles in this column and elsewhere [17][18][19] ; whereas the use of preconception exposure controls, sibling controls, and paternal exposure controls may offer better insights, these research designs are also not infallible. [20][21][22] The bottom line is that no matter how ingenious the research design is and no matter how careful the adjustment for confounding is, observational studies cannot establish that an exposure causes an outcome.…”

Section: Critical Appraisal: General Commentsmentioning

confidence: 99%

Risk of Major Congenital Malformations Associated With the Use of Methylphenidate or Amphetamines in Pregnancy

2018

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“…In effect, observational studies can identify significant associations but can never ascribe causality to those associations. 8,9 As an example, if there was systematic bias in prescribing psychostimulants to more severely ill patients and atomoxetine to less severely ill patients, and if the ADHD behaviors that predisposed to adverse gestational outcomes were not adequately measured and adjusted for in the analyses, then no amount of statistical manipulation would satisfactorily adjust for confounding by indication. This could well be a reason why atomoxetine was not associated with adverse gestational outcomes, although psychostimulants were.…”

Section: Critical Commentsmentioning

confidence: 99%

Adverse Gestational Outcomes Associated With Attention-Deficit/Hyperactivity Disorder Medication Exposure During Pregnancy

2018

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