Prediabetic Levels of Hyperglycemia as a Predictor of Microvascular Angina with Possible Involvement of Low Levels of High-Density Lipoprotein Cholesterol and Hemoglobin

BackgroundThe management of modifiable risk factors, including conventional risk factors, can play an important role in the treatment for microvascular angina (MVA). The purpose of this study was to clarify the clinical characteristics of MVA in a case-control study, thereby elucidating the pathogenesis and management of MVA. MethodsThis study enrolled 92 consecutive patients with MVA (39 men, 53 women, mean age 63.2 {+/-}12.1 years) without obstructive coronary artery disease ([&ge;]50% stenosis) or acetylcholine-provoked epicardial coronary spasms between 1993 and 2015. This study enrolled 691 age-matched Japanese participants (466 men, 225 women, mean age 62.9 {+/-}11.0 years) without a history of chest pain or cardiovascular diseases between 2006 and 2012 as controls. ResultsIn multivariate logistic regression analysis, elevated haemoglobin A1c (HbA1c) (per 1 mmol/mol), low high-density lipoprotein cholesterol (HDL-C) (per 1mmol/L), and low haemoglobin (Hgb) (per 10xg/L) levels were significantly associated with MVA (odds ratio [OR] 1.07[1.04-1.10], p <0.001; OR 0.13[0.06-0.29], p <0.001; OR 0.56[0.44-0.72], p <0.001, respectively). However, the difference between the prevalence of diabetes in MVA patients vs. the prevalence in controls was not significant. MVA patients without diabetes had significantly higher HbA1c levels than control patients without diabetes (39{+/-}4 mmol/mol vs. 34{+/-}3 mmol/mol, respectively; p <0.001). These results were also true for patients and controls stratified by sex. A higher prevalence of proteinuria and lower mean corpuscular volume of erythrocytes were found in MVA patients than in controls stratified by sex. ConclusionsHyperglycaemia reflected by mildly elevated HbA1c levels, (i.e., prediabetes) may be a risk factor for MVA. Low levels of HDL-C and Hgb may also be risk factors for MVA. MVA could be one of the systemic manifestations of microvascular diseases. The study may aid in identifying high-risk MVA patients, allowing increased monitoring and treatments for them. What is already known on this topicMicrovascular angina (MVA) has been attracting attention of clinical research because MVA can be associated with future cardiovascular events. The management of modifiable risk factors, including conventional risk factors, can play an important role in the treatment of MVA because there is currently no specific treatment of MVA. The purpose of this study was to clarify the clinical characteristics of MVA. What this study addsHyperglycaemia reflected by mildly elevated haemoglobin A1c levels, (i.e., prediabetes) may be a risk factor for MVA. Low levels of high-density lipoprotein cholesterol and haemoglobin may also be risk factors for MVA. A higher prevalence of proteinuria and lower mean corpuscular volume of erythrocytes were found in MVA patients than in controls stratified by sex. How this study might affect research, practice or policyMVA could be one of the systemic manifestations of microvascular diseases. The study findings may aid in identifying high-risk patients with MVA, allowing increased monitoring and treatments for them.