RESUMEN
BACKGROUND: This meta-analysis was conducted given the contradictory findings from studies on the influence of diabetes duration or age at onset on mortality in patients with insulin-dependent diabetes mellitus (IDDM). METHODS: Electronic databases (PubMed, Embase, Cochrane, Web of Knowledge, Scopus, and CINHAL) were comprehensively searched to identify relevant studies until October 31, 2022. All of the selected articles contained statistics on hazard ratios, relative risks (RRs), or odds ratios, or data for estimating the association between diabetes duration or age at onset and total mortality in IDDM patients. Regardless the heterogeneity assessed by the I2 statistic, pooled RRs and 95% confidence intervals (CI) for total mortality were acquired via random effect meta-analysis with inverse variance weighting. RESULTS: This meta-analysis finally included 19 studies involving 122, 842 individuals. Both age at onset and diabetes duration were positively associated with an increased mortality rate in IDDM patients. Specifically, the pooled RRs for age at onset and diabetes duration were 1.89 (95%CI 1.43-2.50) and 1.89 (95%CI 1.16-3.09) respectively. Subgroup analyses revealed that only prepubertal onset was associated with a greater survival advantage than pubertal or postpubertal onset. CONCLUSIONS: The findings of this meta-analysis and systematic review suggest that a later age at onset or longer diabetes duration is associated with increased risk of total mortality in IDDM patients. However, this conclusion shall be interpreted with caution due to the possibility of residual confounding and be confirmed in the future by well-designed studies.
RESUMEN
AIM: To determine the effects of laser photocoagulation on serum levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), soluble angiopoietin receptor Tie-2 (Tie-2), Ang-1/Ang-2 ratio and vascular endothelial growth factor (VEGF) in patients with type 2 diabetes mellitus (T2DM) and proliferative diabetic retinopathy (PDR). We also explored the role of the Ang/Tie system in PDR. METHODS: 160 patients with T2DM, including 50 patients with non-diabetic retinopathy (NDR), 58 patients with non-proliferative diabetic retinopathy (NPDR), and 52 patients with PDR were enrolled in this study. Serum Ang-1, Ang-2, Tie-2 receptor and VEGF levels were measured using enzyme-linked immunosorbent assays for all patients and were repeated in 26 patients who underwent laser photocoagulation two months after the procedure. RESULTS: The median levels of Ang-2 and VEGF in serum were significantly higher in the NPDR group (4.23 ng/mL and 303.2 pg/mL, respectively) compared to the NDR group (2.67 ng/mL and 159.8 pg/mL, respectively, P<0.01), with the highest level in the PDR group (6.26 ng/mL and 531.2 pg/mL, respectively, P<0.01). The median level of Ang-1 was significantly higher in the NPDR group (10.77 ng/mL) compared to the NDR group (9.31 ng/mL) and the PDR groups (9.54 ng/mL) (P<0.05), while no difference was observed between the PDR and NDR groups. Ang-1/Ang-2 ratio of PDR group was lowest in three groups (1.49 vs 2.69 and 2.90, both P<0.01). The median level of Tie-2 was not significantly different among three groups (P>0.05). Ang-2 was positively correlated with VEGF and Tie-2 in the PDR and NPDR groups (both P<0.05). Among the 26 patients who underwent laser photocoagulation, serum Ang-2 and VEGF levels significantly decreased (both P<0.05), whereas serum Ang-1 level and Ang-1/Ang-2 ratio were weakly increased (P>0.05). The median levels of Ang-2 and VEGF in serum were highest in PDR group, however, Ang-1/Ang-2 ratio of PDR group was lowest in three groups. CONCLUSION: Laser photocoagulation can reduce serum Ang-2 and VEGF levels. The Ang/Tie system and VEGF play an important role in the development and progression of T2DM patients with PDR.