Risk Factors and Complications Associated With Diabetes Mellitus in Patients With Heart Failure: a Case-control Study.

Abstract

Introduction Globally, heart failure (HF) is among the leading causes of morbidity and mortality within the spectrum of adults with cardiovascular diseases. Its prevalence has been said to sharply increase in the western population, 10% of 75-year-old and above have HF, which is an increase from 1% in 40-year-old. It is responsible for about 30% of all hospital admission in Sub-Saharan Africa and 7% in general areas. Heart failure (HF) patients have a higher probability of having preexisting co-morbidities or developing concomitant diseases such as diabetes mellitus (DM), predominantly type 2 diabetes. These patients face a substantial risk of in-hospital mortality and re-hospitalization. DM, majorly type 2 diabetes, affects nearly 390 million people worldwide, which is expected to increase. Majority of the patients suffering from HF have DM. This close relationship to some extent is because of commonality of some of the risk factors for HF, such as hypertension, obesity, sleep apnea, advanced age, and dyslipidemia, are also found in patients with DM. Research done on this topic was done nearly 20 years ago and therefore there is paucity of data. Objective: To determine the risk factors and complications associated with DM in HF patients Methodology: This was a case control study based in Nairobi County, at the Heart Clinic and Diabetes clinic in Aga Khan University Hospital Nairobi (AKUHN). All patients with HF with an EF of ≤ 40% and DM (a fasting blood glucose of >7.5mmol/l and HbA1c of >6.5 mmol/l) were included in the study. Data collection was undertaken after approval from the Kenyatta National Hospital/UoN-Ethics and Research Committee (KNH/UoN-ERC) and NACOSTI. Recruitment of participants into the study was done using a systemic random sampling with the first participant chosen randomly. Once a case was chosen, a control within five years the age of the case was chosen. The controls are age-matched individuals with HFrEF without DM. Collection of data was done using a structured questionnaire and secondary data was collected from both electronic and medical records. Questions were checked for completeness and were entered into MS excel ready for analysis. Data was then analyzed using R and R-studio. Associations were assessed using the odds ratio (OR) and statistically significant findings were considered significant at a p-value of <0.05. Results: A total of 377 participants were recruited into the study, 143 cases and 234 controls. In social demographic findings, the mean age for the entire population with HF was 59.1 years with an SD of 11.17. The median age was 61 years. In the whole population, there were 29.4% and 30.3% of women in the case and control groups respectively. Among the cases and control group, men and women comprised 70.6% and 69.7%, respectively. In univariable analysis, there was no statistically significant association between sex and ethnicity with DM (P-0.842 and P- 0.567) respectively. Obesity was determined by BMI and was categorized into underweight, normal weight, overweight and obese. Being underweight had a positive non-statistically significant association with DM (p-value = 0.152). Level of Education, hypertension, Heart attack, CAD, Holter, myocardial perfusion tests, ischemic cardiomyopathy, non-ischaemic cardiomyopathy, anaemia and peripartum cardiomyopathy were associated with the onset of DM among HF patients with a p value of less than 0.20 (P-0.20). In multivariable analysis, those who were hypertensive had approximately three times the odds of developing DM among HF patients at an adjusted odds ratio of (aOR – 2.78 95% CI: 1.73-4.46). Heart attack and CAD were not statistically significantly associated with DM (aOR-1.22, 95% CI: 0.65-2.28) and (aOR-1.17 95% CI: 0.66-2.08) respectively. Those who had ischemic cardiomyopathy were not likely to develop DM (aOR-1.13, 95% CI: 0.71-1.81) while peripartum cardiomyopathy and atrial fibrillation showed a statistically significant association with DM (aOR-0.12, 95% CI: 0.01-0.99) (aOR- 0.08 95% CI: 0.01-0.68) respectively. Conclusion: DM patients are twice as likely to develop microvascular and macrovascular complications compared to non-DM patients. Hypertension, Atrial Fibrillation, Peripartum cardiomyopathy were identified as some of the complications of DM in HF Patients. Therefore, DM patients should undergo regular screening for these complications and early interventions be carried out. Recommendation: Further investigation to be carried out with a larger population in order to determine the strength of association of the risk factors and complications of DM in HF patients.