A recent paper published in the The Lancet Diabetes and Endocrinology is the first to examine the influence of multiple manifestations of microvascular disease on the risk of cardiovascular disease in a large population cohort. Researchers and clinicians from St George's University Hospitals NHS Foundation Trust and Imperial College London looked at data on 49,027 patients with type 2 diabetes from the UK Clinical Practice Research Datalink. The presence of isolated retinopathy, peripheral neuropathy, or nephropathy, independent of conventional risk factors, were found to confer at least a similar risk of cardiovascular events as uncontrolled established risk factors including blood pressure (≥140/90 mmHg), HbA1c (≥7.0%) and low-density cholesterol (≥ 2.5 mmol/L). Individuals with disease in multiple microvascular beds were, in a "dose dependent fashion", at the greatest overall risk of cardiovascular disease. For individuals with one, two or three microvascular disease states versus none, the multivariable-adjusted hazard ratios for the primary outcome were 1·32 (1·16-1·50), 1·62 (1·42-1·85) and 1.99 (1·70-2.34), respectively. Similar trends were observed for cardiovascular death, all-cause mortality and for hospitalisation for heart failure. It might be possible to mitigate against this excess risk, as researchers observed that among those with multiple microvascular disease states, event rates were substantially lower when HbA1c, BP and LDL-C were better controlled.
The inclusion of microvascular disease variables in cardiovascular risk algorithms resulted in a net correct reclassification of 3.6% of the cohort into higher- or lower-risk strata that are currently used in the UK and US to determine the need for preventive treatments such as statins. If information on microvascular disease were incorporated presently then 9·3% of individuals previously considered as eligible for moderate intensity statins in US guidance (predicted risk
In reference to UK NICE guidance, of those currently considered ineligible for statin therapy (predicted risk
The authors concluded that as the assessment of microvascular disease should be part of routine clinical practice among those with diabetes, the findings could offer a simple, convenient and cheap method for improving risk prediction as compared to more expensive blood based biomarkers or non-invasive imaging modalities for better targeting preventive therapies. High microvascular disease burden could be used as criteria to enrich future clinical outcome trials, identifying a very high risk cohort of patients who might derive greater absolute benefit from more intensive risk factor control with conventional or novel therapies. It is hoped that the observations should encourage further research including a better understanding of the impact of microvascular disease with different cardiovascular outcomes.
Article: Microvascular disease and risk of cardiovascular events among individuals with type 2 diabetes: a population-level cohort study, Brownrigg JRW, MRCS, Hughes CO, MRCS, Burleigh D, MSc, Karthikesalingam A, PhD, Patterson BO, PhD, Holt PJ, PhD, Thompson MM, MD, de Lusignan S, MD, Ray KK, MD, MPhil, Hinchliffe RJ, MD, The Lancet Diabetes and Endocrinology, doi: 10.1016/S2213-8587(16)30057-2, published online 20 May 2016.