Risk of dry eye in headache patients: a systematic review and meta-analysis

The objective of this meta-analysis was to identify whether headache increase the risk of dry eye disease (DED).PubMed, Web of Science, Cochrane Library and EMBASE databases were searched for relevant studies. The odds ratio (OR) of DED in all-cause headache was calculated via Stata software. To explore the source of heterogeneity, subgroup and sensitivity analyses were conducted. Funnel plots and Egger's test were performed to assess publication bias.This meta-analysis included 11 studies. Pooled analysis indicated that all-cause headache was related to a higher risk of DED (OR = 1.586, 95% CI : 1.409-1.785, I2 = 89.3%, p < .001). Migraine headache, tension headache and cluster headache were all related to a higher risk of DED (OR = 1.503, 95% CI: 1.369-1.650, I2 = 81.8%, p < .001; OR = 1.610, 95% CI: 1.585-1.635, p < .001; OR = 2.120, 95% CI: 1.104-4.073, p = .024), respectively. The risk of DED in case-control studies was slightly higher than in cross-sectional studies and cohort study (OR = 1.707, 95% CI: 1.291-2.258, I2 = 85.0%, p < .001; OR = 1.600, 95% CI: 1.590-1.610, I2 = 0.0%, p < .001; OR = 1.440, 95% CI: 1.096-1.893, p = .009), respectively. Subgroup analysis in territory type showed that all-cause headache in America, Europe, Asia and Oceania were all related to a higher risk of DED.This study indicates that headache is related to a higher risk of DED, especially in the migraine patients. These results suggest that headaches should be regarded as an independent risk factor for DED.KEY MESSAGESIn this meta-analysis, 11 studies (one cohort study, four case-control studies and six cross-sectional studies) covering 3,575,957 individuals were included.Pooled analysis indicated that all-cause headache was related to a higher risk of dry eye (OR = 1.586, 95% CI: 1.409-1.785, I2 = 89.3%, p < .001).These results suggest that headaches should be regarded as an independent risk factor for dry eye.