Admission to hospital with acute gout is associated with a short term increased risk of major adverse cardiovascular events: a longitudinal, population-level linked health data study in Western Australia

Introduction: Cardiovascular disease is the largest contributor to the increased mortality seen in gout. Acute inflammation, which is characteristic of gout, may have a mechanistic role in Major Adverse Cardiovascular Events (MACE).

Hypothesis: TA temporal relationship exists between admissions to hospital with acute gout, and major adverse cardiovascular events, in a large population based administrative health data set using the self-controlled case series study design

Methods: Data were extracted from the Hospital Morbidity Data Collection (from 1970) and Death Registrations (from 1969) of the Western Australian Rheumatic Disease Epidemiology Registry. Participants were patients admitted to hospital with first-ever acute gout (ICD-9: 274; ICD-10: M10) between 1990 and 2010 and had an admission or death due to MACE (ICD-9: 410, 411.1, 428, 430-438; ICD-10: I20-I25, I45-I46, I50, I60-169) during the at risk periods (1-10, 11-20 and 21-30 days after acute gout admission) and control period (365 days prior to admissions and 31-365 days after acute gout admission). We used a self-controlled case-series design (within person design which controls for time-constant patient-specific confounding) and performed a conditional fixed-effects Poisson regression to compare the risk of MACE in the at-risk periods to the control periods.

Results: We identified 835 patients (average age=75.1 years, SD=12.1; 67.4% male) with first-ever acute gout admission and a documented MACE in the control or at-risk periods. An increased risk of MACE was observed in the 1-10 days (Incidence rate ratio [IRR]=3.07, 95%CI: 2.19-4.31), 11-20 days (IRR=2.81, 95%CI: 1.97-4.00), 21-30 days (IRR=1.93, 95%CI: 1.27-2.95) compared to the control period.

Conclusion: Our self-controlled case series study shows an increased risk of MACE in the first 30 days following a first-ever gout admission and suggests a temporal association between acute inflammation and MACE.