Cardiac Abnormalities in Relation to the Disease Activity Index Among Systemic Lupus Erythematosus Patients in a Tertiary Hospital: A Cross-Sectional Study

Abstract

Background: Systemic lupus erythematosus (SLE) is a multisystem autoimmune connective tissue disorder involving multiple organs and systems. Cardiovascular involvement in SLE patients is a major cause of morbidity and mortality. Although subclinical cardiac abnormalities exist among SLE patients, they are rarely screened for. Echocardiography has been demonstrated to be a useful tool for the early diagnosis of cardiac abnormalities in SLE patients, many of which are clinically silent. Early recognition of cardiovascular abnormalities is vital for the prompt initiation of the appropriate management. This study aims to determine the prevalence of various structural and functional cardiac abnormalities among SLE patients and to determine its association with the modified SLE Disease Activity Index 2000 (modified SLEDAI-2K).

Methods: The study was a cross-sectional study of SLE patients at the Korle-Bu Teaching Hospital (KBTH), Accra, Ghana, from June to December 2021. The setting was the rheumatology outpatient clinic of the KBTH and included adult men and women, 18 years and above, diagnosed with SLE with no known cardiac abnormalities. The baseline demographic and clinical characteristics of the participants were determined. A detailed transthoracic echocardiogram was performed for all patients. The frequency of common cardiac pathologies was determined and compared between those with a high modified SLEDAI-2K and those with a low modified SLEDAI-2K.

Results: Ninety-nine SLE patients participated in the study with a mean age of 35.12 years. Females formed the majority (90.9%) of the participants. The mean age at diagnosis of SLE was 28.7 years and the mean disease duration was 4.6 years. All of the participants were on at least two disease-modifying medications. The mean modified SLEDAI-2K score was 9.1. Thirty-five percent (35%) of the patients had mild to moderately active disease and 39% had severely active disease. Sixty-six (66%) out of the severely active disease group had abnormal echocardiographic findings, while 28% of those with mild to moderate disease had abnormal echocardiographic findings. Echocardiographic abnormalities were found in 56 patients (47%), out of which 8.7% had valvular involvement, 15.7% had diastolic dysfunction, 5.2% had left ventricular hypertrophy (LVH), and 0.9% had left ventricular systolic dysfunction (LVSD). About 12% of the participants had pulmonary hypertension and 1% had pericardial involvement. The odds of echocardiographic abnormalities were 13.7 times higher in SLE patients with high disease activity compared to those with low disease activity (odds ratio (OR) = 13.714, 95% confidence interval (CI) = 3.804-49.442, p < 0.001). There was no significant association between cardiac abnormalities and SLE duration. No significant correlation between cardiac abnormalities and modified SLEDAI-2K score was found. Conclusion: Cardiac abnormalities, especially left ventricular diastolic dysfunction (LVDD), valvular involvement, and pulmonary hypertension, are common in SLE patients. For SLE patients, especially those with active diseases, echocardiographic assessment should be considered in the management of SLE patients to enable early detection of cardiac abnormalities, early treatment, and thus a decrease in morbidity and mortality associated with cardiovascular involvement in SLE patients.

Keywords: autoantibody production; autoimmune disease; cross-sectional study; disease activity index; echocardiographic; immune complex deposition; systemic lupus erythematosus (sle).

Figure 1. Systemic lupus erythematosus (SLE) disease activity classification