Drivers of hospitalisation trends for non-valvular atrial fibrillation in Western Australia, 2000–2013

Objective
To determine if increasing hospitalisations for non-valvular atrial fibrillation (NVAF) in Western Australia (WA) was due to incident (first-ever) or repeat hospitalisations, an ageing population structure, changing procedural practice or a combination of these factors.

Methods
We conducted a longitudinal retrospective population study on all WA residents aged 25–94 years between 2000 and 2013, with a principal hospital discharge diagnosis of NVAF. Person-linked hospital morbidity and mortality records were used to measure annual rate ratios (RRs) and 95% confidence intervals (CIs) in the total and incident NVAF (25–94 years) hospitalisations, further stratified by sex and by age-specific standardised groups (25–44, 45–64, 65–75, 75–84, 85–94 years).

Results
There were 55,532 total hospitalisations for NVAF between 2000 and 2013, patient mean age 68.3 years, and 58% male. Annual age- and sex- standardised rates for total NVAF hospitalisation increased by 3.0%/year (RR 1.030; 95%CI; 1.028, 1.038), and in both men and women. The largest absolute increase in hospitalisation rate occurred in those aged 85–94 years (∆613/100,000 men and women combined). Incident NVAF hospitalisations showed a borderline decline of 0.5%/year (RR 0.99; 95%CI; 0.99, 1.0) with a statistically significant trend in women but not men. The rate of AF admissions associated with a catheter ablation increased by 13%/year (95%CI; 13.1%, 15.3%).

Conclusion
The increasing rates of total hospitalisation for NVAF is driven more by repeat than incident admissions, escalating hospitalisations in the very elderly, and more frequent interventional procedures. These drivers have major economic and healthcare planning implications.