RESUMO
Introduction: Uric acid (UA) levels in serum, salivary, and gingival crevicular fluid (GCF) may be associated with periodontal diseases. Hence, this study aimed to estimate the UA concentration in serum, saliva, and GCF of periodontal disease and non-periodontal disease subjects by conducting a systematic review and a meta-analysis of the reported studies. Materials and Methods: A review of the available literature was searched in the electronic databases of PubMed, Cochrane, Science Direct, and EBSCO for the relevant publications. All the related case-control, cross-sectional, and cohort studies reporting the UA levels in the blood, salivary, and GCF between periodontal disease patients and healthy controls were analyzed. Significant heterogeneity was observed in the studies. Hence, a continuous random-effects model was used. The findings are described in forest plots with the point estimations and 95% confidence interval (CI). A value of P less than 5% was considered as a significant heterogeneity test. Results: Of the initial 166 study titles screened, 14 reported papers were eligible for quantitative review. The subgroup analysis of serum UA revealed a mean difference of 0.299 (95% CI: 0.029-0.569, I 2=85.64%, P<0.001), indicating an increase in the UA levels in periodontal disease. However, the subgroup analysis by salivary UA demonstrated a mean difference of -0.783 (95% CI: -1.577-0.011, I 2= 94.62%, P<0.001), suggesting a lower side of the UA level in periodontal diseases. The subgroup analysis based on case-control studies showed a mean difference of 0.004 (95% CI: -0.286-0.294, I 2=84.99%, P<0.001), indicating no changes in UA levels in periodontal disease. On the contrary, cohort studies and cross-sectional studies showed a mean difference : 95% CI: -1.016, -3.272-1.241, I 2=97.84%, P<0.001 and 95%: -1.230, -4.410-1.949, I 2=97.7%, P<0.001, indicating reduction in UA levels in periodontal disease cases. Conclusion: The current review suggests an increase in the serum UA levels in periodontal disease than in healthy controls. Contrarily, the salivary UA levels decreased in periodontal disease patients. It is unknown why UA levels are opposite in the blood and saliva of periodontal disease patients requiring further explanation.
