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Systemic levels of interleukin‐6 in patients with age‐related macular degeneration: a systematic review and meta‐analysis
Author(s) -
Nahavandipour Arvin,
Krogh Nielsen Marie,
Sørensen Torben L.,
Subhi Yousif
Publication year - 2020
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/aos.14402
Subject(s) - macular degeneration , meta analysis , medicine , geographic atrophy , web of science , strictly standardized mean difference , subgroup analysis , medline , relative risk , ophthalmology , confidence interval , political science , law
Age‐related macular degeneration (AMD) is the most prevalent cause of irreversible vision loss in industrialized countries. Several studies have investigated systemic interleukin‐6 (IL‐6) levels of patients with AMD. In this study, we systemically reviewed the literature to provide an overview of the field and used meta‐analyses to provide a summary estimate of the standardized mean difference (SMD) of systemic IL‐6 between patients with AMD and control individuals. We searched the literature databases PubMed/MEDLINE, Embase, Web of Science and the Cochrane Central on 1 June 2019 for relevant studies on humans. Two authors independently extracted data and evaluated risk of bias. We identified 19 studies for the qualitative review with a total of more than 3586 individuals (1865 controls and 1721 with AMD). We found an overall random‐effects SMD in systemic IL‐6 levels 0.63 (95% CI: 0.28 to 0.99, p = 0.0005) corresponding to a medium effect size. In a subgroup analysis, we found that early AMD was not strongly associated with elevated IL‐6 levels (0.12, 95% CI: −0.01 to 0.24, p = 0.06), which was in contrast to the significantly elevated IL‐6 levels in patients with geographic atrophy (1.21, 95% CI: 0.41 to 2.01, p = 0.003) and patients with neovascular AMD (0.99, 95% CI: 0.34 to 1.63, p = 0.003). Our results show that the evidence today suggests an increased systemic IL‐6 in patients with AMD, but that this may be a phenomenon more closely related to the late subtypes of AMD.