A Study on QT Interval in patients with SLE and its Correlation with disease activity and Auto Antibodies.

Sham, S (2014) A Study on QT Interval in patients with SLE and its Correlation with disease activity and Auto Antibodies. Masters thesis, Madras Medical College,Chennai.

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Abstract

INTRODUCTION : Systemic lupus erythematosus (SLE) is the prototype autoimmune disease with varied clinical manifestations due to involvement of a variety of organ systems simultaneously or serially over a period of time. Similar to other rheumatic diseases the disease activity has to be controlled and maintained in a state of remission or low activity. Hence we have to monitor the disease activity periodically and adjust the dosage of medications. The disease can be either in a state of remission or can be chronically active or can be of remitting and relapsing type with intermittent flares. For measuring the disease activity, we do a clinical assessment followed by laboratory investigations. Some of the immunological investigations like anti ds DNA and complements are still not affordable by everybody in a country like ours. The very purpose of this study is to look for other alternatives which can indirectly gauge the disease activity during a flare. AIMS AND OBJECTIVES : To study the correlation between QTc interval parameters and disease activity in patients with SLE. Primary Objectives : 1. To study the correlation between QT interval parameters (QTc interval & QT dispersion) and disease activity in patients with SLE. 2. To study QT interval parameters during episodes of flare (on follow up). Secondary Objectives : 1. To study the correlation between QT interval parameters & auto antibodies. 2. To study the correlation between ESR and disease activity (SLEDAI). 3. To study the correlation between serum uric acid and disease activity (SLEDAI). 4. To find out the correlation between CLASI and disease activity (SLEDAI) in patients with cutaneous manifestations of SLE. MATERIALS AND METHODS : The study was done on newly detected SLE patients admitted in the Department of Rheumatology, Madras Medical College & RGGGH, Chennai . from January 2012 – December 2013. Design of the study: Prospective analytical study. Consent: Informed consent in patients own language was obtained Study group: 100 consecutive SLE patients and 100 age matched controls attending the Department of Rheumatology, RGGGH, Chennai who satisfied the inclusion criteria were studied. Inclusion Criteria: - Patients who satisfied the 1997 revised ACR classification criteria for SLE with a normal good quality resting ECG were included in the study group. - Patients who attended master health check up and other outpatients who had non rheumatological disorders. Exclusion Criteria: - Patients with electrolyte disturbances. - Drugs prolonging QT interval (except chloroquine). - Patients with baseline ECG abnormalities (eg: bundle branch blocks , presence of U waves). - Pre-existing cardiac disease (eg: ischemic heart disease, congestive heart failure, rhythm abnormalities), - Renal failure. All patients who satisfied the inclusion criteria were chosen and detailed history was obtained and complete clinical examination was done. Patients were subjected to baseline blood investigations and immunological investigations. ESR was calculated with Westergren’s method & serum uric acid (determined by Trinder’s method) with automated analyser. ANA was done by either ELISA or IIF by Hep-2 method, anti dsDNA by ELISA & complements by nephelometry. ANA profile 3 was done by EUROIMMUNE Line Immunoassay (Immunoblot). RESULTS : The study group had 59% of the patients (48% - females & 11% - males) in the age group of 21-30 years. There were 24% (22% - females & 2% males) of patients in age group of 17-20 years. The maximum number of patients were from 2nd and 3rd decades. Among the cases 86% were females and 14% were males. Among the controls 75% were females and 25% were males. In our study group 61% had arthritis ,58% had cutaneous,45% had neuropsychiatry, 44% had renal involvement, 43% had serositis, 32% had haematological , 29% had CVS involvement and 41% had myositis. In our study group class IV lupus nephritis was common (38.63%), followed by class III (22.72%) and class V (15.9%). Anti Sm was found in 49%, followed by Anti Ro (47%), Anti ds DNA (45%) and Anti U1RNP(42%). 84% of the patients in our study had high disease activity. In our study group of 100 patients, 25 patients had flare, of which 28% had mild flare, 36% had moderate flare and 36% had severe flare. In our study group, 4% had ESR less than 25 mm/hr, 41% had between 26-50 mm/hr, 41% between 51-75 mm/hr and 14% had ESR between 76-100 mm/hr. In our study group 42 had acute cutaneous lesions, 26 had sub acute cutaneous lesions and 13 had chronic cutaneous lesions. CONCLUSION : There was a significant difference in mean QTc interval between SLE patients and controls. There was a positive correlation between QTc parameters at baseline and during flare but was statistically significant only for severe flare. Patients with anti Ro antibody positivity have significant prolongation of QTc interval. Patients with high disease activity have significant prolongation of QTc interval. There was a significant correlation between ESR and disease activity in SLE. There was a significant correlation between serum uric acid and disease activity in SLE. This study emphasizes the increased prevalence of probably a subclinical atherosclerosis or myocarditis and hence QTc prolongation in SLE patients with high disease activity. Patients with high disease activity and those with anti Ro antibody positivity have to be monitored regularly for increased risk of cardiac arrhythmias and have to be treated promptly. In a developing country like ours, where it may be not possible to repeat anti ds DNA and complements during each flare, parameters like QTc interval, ESR and serum Uric acid may be used as surrogate markers to assess disease activity.

Item Type: Thesis (Masters)
Uncontrolled Keywords: QT Interval ; Patients ; SLE ; Auto Antibodies.
Subjects: MEDICAL > Rheumatology
Depositing User: Subramani R
Date Deposited: 16 Aug 2017 00:44
Last Modified: 16 Aug 2017 05:02
URI: http://repository-tnmgrmu.ac.in/id/eprint/1808

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