title: Cumulative dose of hydroxychloroquine is associated with a decrease of resting heart rate in patients with systemic lupus erythematosus: a pilot study.
abstract: BACKGROUND
  The use of hydroxychloroquine (HCQ) in patients with systemic lupus erythematosus (SLE) offers a wide range of benefits. However, there are evidence in favour of cardiotoxicity, including heart conduction disturbances and congestive heart failure.
  
  
  OBJECTIVE
  To determine the effects of HCQ in the resting heart rate (RHR) of SLE patients.
  
  
  METHODS
  Included were patients with non active SLE, with a sedentary lifestyle and treated with HCQ. Excluded were patients on beta blocker treatment, trained patients, pacemaker's users and patients with clinical or analytical evidence of anemia, renal disease, obstructive pulmonary disease, obesity, uncontrolled thyroid disease, fever or current infection. Standard 12-lead electrocardiogram was performed in the resting condition (supine decubitus and orthostatic position). Comparison between groups was performed using Mann-Whitney U test. A multiple linear regression was performed. A p value <0.05 was considered statistically significant.
  
  
  RESULTS
  42 patients were included. Patients were divided in two groups based on the cumulative dose of HCQ (CD-HCQ), considering 365 g as cut-off. There were 24 patients with low-HCQ (<365 g) and 18 patients with high-HCQ (>365 g). Non significant differences were found in age, sex, prednisone dose or SLEDAI. The mean RHR was 73 ± 6 beats/min in the low-HCQ and 65 ± 7 beats/min in the high-HCQ, with a significant decrease of 11% (p = 0.003). In multiple linear regressions, there were non significant association between the decrease of RHR and prednisone dose, age, SLEDAI or TSH, but there was significant association between RHR and CD-HCQ (p = 0.024) and RHR and time of exposure to HCQ (p = 0.029).
  
  
  CONCLUSIONS
  CD-HCQ higher than 365 g was associated with a significant decrease (11%) in RHR in non-active SLE patients, although a larger prospective study is required to allow more definitive conclusions.
authors: Unidad de Enfermedades Autoinmunes Sistémicas, Clínica Médica 'C', Prof. Dr. Juan Alonso Bao, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay ecairoli@hc.edu.uy.
authors: E
authors: E
authors: Cairoli
authors: Unidad de Enfermedades Autoinmunes Sistémicas, Clínica Médica 'C', Prof. Dr. Juan Alonso Bao, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors: N
authors: N
authors: Danese
authors: Unidad de Enfermedades Autoinmunes Sistémicas, Clínica Médica 'C', Prof. Dr. Juan Alonso Bao, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors: M
authors: M
authors: Teliz
authors: Unidad de Enfermedades Autoinmunes Sistémicas, Clínica Médica 'C', Prof. Dr. Juan Alonso Bao, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors: M J
authors: MJ
authors: Bruzzone
authors: Unidad de Enfermedades Autoinmunes Sistémicas, Clínica Médica 'C', Prof. Dr. Juan Alonso Bao, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors: J
authors: J
authors: Ferreira
authors: Unidad de Enfermedades Autoinmunes Sistémicas, Clínica Médica 'C', Prof. Dr. Juan Alonso Bao, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors: M
authors: M
authors: Rebella
authors: Departamento Básico de Medicina, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
authors: A
authors: A
authors: Cayota
mesh_terms: D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D018501:Antirheumatic Agents / Q000008:administration & dosage* / Q000009:adverse effects*; D066126:Cardiotoxicity / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring / Q000379:methods; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006886:Hydroxychloroquine / Q000008:administration & dosage* / Q000009:adverse effects*; D008180:Lupus Erythematosus, Systemic / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010865:Pilot Projects; D011241:Prednisone / Q000627:therapeutic use; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D000893:Anti-Inflammatory Agents; D018501:Antirheumatic Agents; D006886:Hydroxychloroquine; D011241:Prednisone
keywords: Systemic lupus erythematosus; heart rate; hydroxychloroquine