Diabetes Mellitus as a Risk Factor for Open-Angle Glaucoma: A Systematic Review and Meta-Analysis

<div><p>Objective</p><p>To determine the association between diabetes mellitus (DM) and primary open-angle glaucoma (POAG).</p><p>Methods</p><p>This is a systematic review and meta-analysis of case-control and cohort studies. The literature search included two databases (PubMed and Embase) and the reference lists of the retrieved studies. Separate meta-analyses for case-control studies and cohort studies were conducted using random-effects models, with results reported as adjusted odds ratios (ORs) and relative risks (RRs), respectively.</p><p>Results</p><p>Thirteen studies—seven case-control studies and six population-based cohort studies—were included in this meta-analysis. The pooled RR of the association between DM and POAG based on the risk estimates of the six cohort studies was 1.40 (95% CI, 1.25–1.57). The pooled OR of the association between DM and POAG based on the risk estimates of the seven case-control studies was 1.49 (95% CI, 1.17–1.88). There was considerable heterogeneity among the case-control studies that reported an association between DM mellitus and POAG (<i>P</i><0.001) and no significant heterogeneity among the cohort studies (<i>P</i> = 0.377). After omitting the case-control study that contributed significantly to the heterogeneity, the pooled OR for the association between DM and POAG was 1.35 (95% CI, 1.06–1.74).</p><p>Conclusions</p><p>Individuals with DM have an increased risk of developing POAG.</p></div

Forest figure of success rate comparing Limbus- with Fornix-based trabeculectomy.

<p>(Relative risks (RR) were computed by using a random effects model. 95% CI indicates 95% confidence interval; RCT: prospective randomized controlled trial; Retro: retrospective comparative study; Pro: prospective non-randomized comparative study.)</p

Funnel plot of the case-control studies evaluating the association between DM and POAG.

<p>Begg's regression asymmetry test (<i>P</i> = 0.548). OR = odds ratio; DM = diabetes mellitus; POAG = primary open-angle glaucoma.</p

Forest plot of the risk estimates of the association between DM and POAG in the cohort studies.

<p>RR = risk ratio; CI = confidence interval; DM = diabetes mellitus; POAG = primary open-angle glaucoma.</p

Sensitivity analysis to evaluate the effect of trial design on percentage IOP reduction.

<p>CI  =  confidence interval; IOP  =  intraocular pressure; RCT  =  prospective randomized controlled trial; Retro  =  retrospective; Pro  =  prospective nonrandomized; WMD  =  weighted mean difference.</p

Characteristics of cohort studies of DM and POAG incidence.

<p>1, age; 2, gender; 3, race; 4, Hypertension; 5, body mass index; 6, physical activity; 7, alcohol intake; 8, Smoking; 9, family history of glaucoma; 10, follow-up time; 11, IOP; 12, questionnaire cycle; 13, education.</p><p>DM: diabetes mellitus; EG: exposed group; CG: comparison group; RR: risk ratio; CI: confidence Interval; GVFL: Glaucomatous visual field loss; GON: Glaucomatous optic neuropathy;</p><p>*: Incidence rate ratio;</p>#<p>: hazard ratio.</p

Characteristics of case-control studies of DM and POAG incidence.

<p>1, age; 2, gender;3, race; 4, Hypertension; 5, body mass index; 6, physical activity; 7, alcohol intake; 8, Smoking; 9, family history of glaucoma; 10, follow-up time; 11, IOP; 12, IOP–lowering treatment; 13, questionnaire cycle; 14, education; 15, Myopia; 16, Radiation exposure; 17, thyroid disease; 18, migraine; 19, cardiovascular events; 20, angiotensin-converting enzyme inhibitors.</p><p>DM: diabetes mellitus; OR:odds ratio; CI: confidence Interval; GVFL: Glaucomatous visual field loss; GON: Glaucomatous optic neuropathy.</p

Percentage IOP reduction from baseline comparing Ex-Press implantation with trabeculectomy.

<p>CI  =  confidence interval; IOP  =  intraocular pressure; IOPR%  =  percentage intraocular pressure reduction; WMD  =  weighted mean difference; Ex-Press  =  Ex-Press implantation; Trab  =  trabeculectomy.</p

Intraocular pressure reduction (IOPR) from baseline comparing Limbus- with Fornix-based trabeculectomy.

<p>Weighted mean differences (WMD) were computed by using a random effects model. 95% CI indicates 95% confidence interval; Limbus: Limbus-based conjunctival flaps group; Fornix: Fornix-based conjunctival flaps group; RCT: prospective randomized controlled trial; Retro: retrospective comparative study; Pro: prospective non-randomized comparative study.</p

Characteristics of included studies.

*<p>Ex-Press group/Trab group; RCT  =  prospective randomized controlled trial; Retro  =  retrospective; Pro  =  prospective non-randomized; NA  =  not available; Ex-Press  =  Ex-Press implantation; Trab  =  trabeculectomy.</p