Antidepressants use and risk of cataract development: a systematic review and meta-analysis

Methodological quality of the review: Medium confidence

Author: Fu Y, Dai Q, Zhu L, Wu S.

Region: United Kingdom (UK), Taiwan, United States of America (USA), Canada

Sector: Cataract development 

Sub-sector: Risk factor

Type of cataract: Age-related cataract

Equity focus: None specified

Quantitative synthesis method: Narrative synthesis and meta-analysis

Qualitative synthesis method: Not applicable 

Background:

Epidemiological studies suggest that antidepressants use may increase the risk of cataract, but the results are inconclusive.

Research objectives:

The authors aimed to examine the association between antidepressants and risk of cataract development by performing a systematic review and meta-analysis on all eligible epidemiological studies that provided data on the association of antidepressants use with cataract risk.

Main findings:

Review authors included a total of seven case-control studies in the review, of which four were nested case-control studies. Three were conducted in the USA, two in Canada, and one each in the UK and Taiwan. These studies were published between 2001 and 2017. Overall, authors reported that the combined Odds Ratios (ORs) (95% confidence intervals) of cataract for selective serotonin reuptake inhibitors (SSRIs), serotonin noradrenalin reuptake inhibitors (SNRIs), and tricyclic antidepressants (TCAs) were 1.12 (1.06–1.19), 1.13 (1.04–1.24), and 1.19 (1.11–1.28), respectively. A certain degree of heterogeneity was observed by the authors across studies (P < 0.001, I2 = 92.2% for SSRIs, P = 0.026, I2 = 67.5% for SNRIs, and P = 0.092, I2 = 58.0% for TCAs).

Based on the funnel plot assessment, authors report a slight degree of publication bias within the review.

Based on the findings of this review, authors concluded that there is a significant association between antidepressants use and risk of cataract. However, due to heterogeneity and limited eligible studies, authors note that further prospective studies are needed to confirm the preliminary findings of this review.

Methodology:

Authors conduct a search on PubMed and Web of Science databases through 2017, where no restrictions were applied. Cited references of retrieved articles were also screened.

Studies were eligible for inclusion if:  1) had cohort, nested case-control or case-control study design; 2) the exposure of interest was antidepressants use, including SSRIs, TCAs, serotonin noradrenalin reuptake inhibitors (SNRIs), and so on; 3) the endpoint of interest was cataract incidence; and 4) the risk estimate and the corresponding 95% confidence interval (CI) were reported. If multiple studies used the same population, we included the study with the largest sample size. Authors extracted data of included studies using a standard data-collection form and assessed the quality of individual studies using the Newcastle-Ottawa scale. Study selection, data extraction and quality assessment were conducted by two reviewers individually.

Authors conducted a meta-analysis using a DerSimonia and Laird random-effects model. For studies that separately provided estimated risk estimates for a number of categories of exposure compared with a single reference category, authors combined these risk estimates within each study using the method reported by Hamling et al’s study. Homogeneity across included studies was tested by Q statistics at the P < 0.10 level of significance. The I2 score, a quantitative measure of inconsistency across studies, was also calculated by the authors. Potential publication bias was assessed by a visual funnel plot. All analyses were performed by using STATA version 10.0 (StataCorp, College Station, TX). A P value < 0.05 was considered statistically significant, except where otherwise specified.

Applicability/external validity:

Authors do not discuss applicability and/or external validity of the results.

Geographic focus:

Authors note that although most included studies were performed in western countries, population characteristics still varied in genetic and environmental background, antidepressants use, and matched or adjusted confounders.

Quality assessment:

Medium confidence was attributed in the conclusions about the effects of this study. Authors used appropriate methods to search, select, extract data and assess the quality of included studies. However, authors did not contact authors/experts as part of the search strategy. Although authors reported the overall score for each included study, the limitations of each study are not clear. Authors acknowledge the presence of heterogeneity across included studies and do not draw strong policy conclusions.