Exploring the relationship between coronary heart disease and type 2 diabetes: a cross-sectional study of secondary prevention among diabetes patients.

RESEARCH Exploring the relationship between coronary heart disease and type 2 diabetes: a cross-sectional study of secondary prevention among diabetes patients Bjørn Gjelsvik, MD, PhD1*, Anh Thi Tran, MD, PhD2, Tore J Berg, MD, DrMedSci3,4, Åsne Bakke, MD5,6, Ibrahimu Mdala, PhD7, Kjersti Nøkleby, MD8, John G Cooper, MD9,10, Tor Claudi, MD11, Karianne Fjeld Løvaas, MSc12, Geir Thue, MD, DrMedSci13,14, Sverre Sandberg, MD, DrMedSci15,16,17, Anne K Jenum, MD, DrMedSci18 1 *For correspondence: bjorn. Competing interests: The authors declare that no competing interests exist. Received: 05 December 2018 Accepted: 17 December 2018 Published: 20 March 2019 This article is Open Access: CC BY license (https:// creativecommons.org/licenses/ by/4.0/) Author Keywords: type 2 diabetes, coronary heart disease, stroke, secondary prevention, general practice, primary care Copyright s 2019, The Authors; DOI:10.3399/ bjgpopen18X101636 Assistant Professor, Department of General Practice, General Practice Research Unit (AFE), Institute of Health and Society, University of Oslo, Oslo, Norway; 2 Researcher, Department of General Practice, General Practice Research Unit (AFE), Institute of Health and Society, University of Oslo, Oslo, Norway; 3Assistant Professor, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; 4Senior Consultant, Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway; 5Senior Consultant, Department of Medicine, Stavanger University Hospital, Stavanger, Norway; 6PhD Fellow, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; 7Statistician, Department of General Practice, General Practice Research Unit (AFE), Institute of Health and Society, University of Oslo, Oslo, Norway; 8PhD Fellow, Department of General Practice, General Practice Research Unit (AFE), Institute of Health and Society, University of Oslo, Oslo, Norway; 9Researcher, Norwegian Quality Improvement of Laboratory Examinations, Haraldsplass Deaconess Hospital, Bergen, Norway; 10Senior Consultant, Department of Medicine, Stavanger University Hospital, Stavanger, Norway; 11Senior Consultant, Department of Medicine, Nordland Hospital, Bodø, Norway; 12Section Head, Norwegian Quality Improvement of Laboratory Examinations, Haraldsplass Deaconess Hospital, Bergen, Norway; 13Professor, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; 14Professor, Norwegian Quality Improvement of Laboratory Examinations, Haraldsplass Deaconess Hospital, Bergen, Norway; 15Professor, Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway; 16 Professor, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; 17Director, Norwegian Quality Improvement of Laboratory Examinations, Haraldsplass Deaconess Hospital, Bergen, Norway; 18Professor, Department of General Practice, General Practice Research Unit (AFE), Institute of Health and Society, University of Oslo, Oslo, Norway Abstract Gjelsvik B et al. BJGP Open 2019; DOI: 10.3399/bjgpopen18X101636 1 of 11 Research Background: Coronary heart disease (CHD) and stroke are the major causes of death among people with diabetes. Aim: To describe the prevalence and onset of CHD and stroke among patients with type 2 diabetes mellitus (T2DM) in primary care in Norway, and explore the quality of secondary prevention. Design & setting: A cross-sectional study of data was undertaken from electronic medical records (EMRs) of 10 255 patients with T2DM in general practice. The study took place in five counties of Norway (Oslo, Akershus, Rogaland, Hordaland, and Nordland). Quality of care was assessed based on national guideline recommendations. Method: Summary statistics with adjustments and binary logistic regression models were used. Results: In total, 2260 patients (22.1%) had CHD and 759 (7.4%) had stroke. South Asians had significantly more CHD than ethnic Norwegians (29.5%, 95% confidence interval [CI] = 26.1 to 33.0 versus 21.5%, CI = 20.6 to 22.3) and other ethnic groups, and experienced onset of CHD or stroke at a mean of 7 years before Norwegians. In 47.9% of the patients, CHD was diagnosed before T2DM. Treatment target for low-density lipoprotein (LDL) cholesterol was reached for 30.0% and for systolic blood pressure (SBP) for 65.1% of the patients with CHD. Further, 20.9% of patients with CHD were present smokers, and only 5.0% of patients reached all four treatment targets (no smoking, HbA1c 7.0%, SBP <135 mmHg, LDL-cholesterol <1.8 mmol/l). Conclusion: The diagnosis of CHD preceded the diagnosis of T2DM in half of the patients. The prevalence of CHD was highest and onset earlier among ethnic South Asians. More intensive treatment of lipids, blood pressure, and smoking are needed in patients with T2DM and CHD. How this fits in CHD and stroke are prevalent among people with T2DM, and are generally thought to be a complication of diabetes. However, this survey found that diagnosis of CHD preceded the diagnosis of T2DM in half of the patients. An increased prevalence and earlier onset of CHD was also found among people of South Asian ethnicity. Only 30.0% of CHD patients reached treatment target for LDL-cholesterol, and more intensive care is needed for people with multiple elevated risk factors. Introduction CHD and stroke are the major causes of death among people with diabetes.1 T2DM has been associated with a doubling of the risk for CHD and stroke,2 although a somewhat lower risk has recently been reported in Scandinavia.3,4 Cardiovascular disease (CVD) among patients with T2DM places pressure on the healthcare system,5,6 but multifactorial secondary prevention reduces morbidity and years of life lost.7–9 The influence of chronic hyperglycaemia on atherosclerosis is not fully understood,10 and studies describing the relation between the onset of CVD and of T2DM are few. There has, however, been an increasing awareness of diagnosing T2DM among patients with CHD. Recently, statins have been shown to exert a diabetogenic effect,11,12 which also may contribute to an increasing prevalence of T2DM among patients with CHD. GPs follow up most patients with T2DM in Norway; therefore, the quality of care in general practice is essential for the clinical outcomes of these patients. The aims in the present article were: firstly, to describe the prevalence of CHD and stroke among patients with T2DM, time of onset, and distribution according to age, sex, ethnic group, and region in a primary care setting in Norway; and secondly, to characterise the secondary preventive efforts among T2DM patients with CHD and stroke to identify potential treatment gaps, and identify patient and GP factors associated with successful achievement of treatment goals. Gjelsvik B et al. BJGP Open 2019; DOI: 10.3399/bjgpopen18X101636 2 of 11 Research Method The study is part of the (...truncated)