Author + information
- Jianbo Zhou and
- Jinkui Yang
To examine and quantify the potential relation between diabetic retinopathy and risk of all cause mortality, coronary hearts diseases (CHD), stroke and heart failure.
Meta-analysis of epidemiological observational studies from Pubmed, EMBASE, CINAHL, Cochrane Library, conference, and proceedings. Random or fixed effects models were used to calculate pooled hazard ratios and 95% confidence intervals and to incorporate variation between studies. Summary hazard ratios were estimated. Potential sources of heterogeneity and bias were explored.
Of the included 40 studies, comprising 158,698 participants, twenty studies were included to explore the relation of DR to all-cause mortality, six about CHD events, five about stroke, and four about heart failure.
RR for all-cause mortality of the presence of DR was 2.33 (95% CI 1.92-2.81) compared with diabetic individuals without DR. Evidences showed a higher risk of all cause mortality associated with DR in patients with T2D or T1D (RR2.25, 95 % CI 1.91-2.65. RR2.68, 95% CI 1.34-5.36). According to different grades of DR in patients with T2D, RR for all-cause mortality varied either, the risk of NPDR was 1.38(1.11-1.70), PDR of 2.32(1.75-3.06). There was no evidence of significant heterogeneity (Cochran's Q test P=0.29vs 0.26, I2=19.6%vs 22.6% respectively).
In the pooled analysis of the six included studies, RR for CHD with DR patients was 1.75(95% CI 1.45-2.11), compared with patients without DR in T2D. According to different grades of DR in T2D, RR for CHD with NPDR was 1.38(1.18-1.62), PDR of 2.18(1.42-3.34). There was no evidence of significant heterogeneity (Cochran's Q test P = 0.35 vs 0.11,I2=9.4% vs 50%).
Data from the five studies on DR and the risk of stroke showed that DR was associated with a significantly increased risk of stroke (pooled RR =1.74, 95%CI: 1.35-2.24), compared with patients without DR. DR (as compared with individuals without DR) was marginal associated with a significant increase in the risk of heart failure in patients with DM (n =4 studies; RR 2.24, 95% CI 0.98-5.14, P = 0.056).
Our findings agree with the concept that diabetic retinopathy and cardiovascular and cerebral-vascular events may have shared certain patho-physiological mechanisms. Clearly, future studies are needed to verify this hypothesis and to perhaps uncover other non-circulatory backgrounds that could explain the risk of diabetic retinopathy.