Large regional variation in cardiac closure procedures to prevent ischemic stroke in Switzerland a population-based small area analysis

Abstract

Background: Percutaneous closure of a patent foramen ovale (PFO) or the left atrial appendage (LAA) are controversial procedures to prevent stroke but often used in clinical practice. We assessed the regional variation of these interventions and explored potential determinants of such a variation.

Methods: We conducted a population-based analysis using patient discharge data from all Swiss hospitals from 2013-2018. We derived hospital service areas (HSAs) using patient flows for PFO and LAA closure. We calculated age-standardized mean procedure rates and variation indices (extremal quotient [EQ] and systematic component of variation [SCV]). SCV values >5.4 indicate a high and >10 a very high variation. Because the evidence on the efficacy of PFO closure may differ in patients aged <60 years and ≥60 years, age-stratified analyses were performed. We assessed the influence of potential determinants of variation using multilevel regression models with incremental adjustment for demographics, cultural/socioeconomic, health, and supply factors.

Results: Overall, 2574 PFO and 2081 LAA closures from 10 HSAs were analyzed. The fully adjusted PFO and LAA closure rates varied from 3 to 8 and from 1 to 9 procedures per 100,000 persons per year across HSAs, respectively. The regional variation was high with respect to overall PFO closures (EQ 3.0, SCV 8.3) and very high in patients aged ≥60 years (EQ 4.0, SCV 12.3). The variation in LAA closures was very high (EQ 16.2, SCV 32.1). In multivariate analysis, women had a 28% lower PFO and a 59% lower LAA closure rate than men. French/Italian language areas had a 63% lower LAA closure rate than Swiss German speaking regions and areas with a higher proportion of privately insured patients had a 86% higher LAA closure rate. After full adjustment, 44.2% of the variance in PFO closure and 30.3% in LAA closure remained unexplained.

Conclusions: We found a high to very high regional variation in PFO closure and LAA closure rates within Switzerland. Several factors, including sex, language area, and insurance status, were associated with procedure rates. Overall, 30-45% of the regional procedure variation remained unexplained and most probably represents differing physician practices.

Fig 1. Variation in age- and sex-standardized PFO or LAA closure procedure rates per 100,000 persons across 10 Swiss hospital service areas (average rate for calendar years 2013–2018).

PFOC = PFO closure. LAAC = LAA closure. Average age-/sex-standardized procedure for each HSA per 100,000 persons.

Fig 2

Average predicted (A) PFO or (B) LAA procedures across 10 Swiss HSAs derived from models with progressive adjustment. HSA = hospital service area. Average predicted procedures rates for each HSA are shown as red-scale categories per 100,000 persons. Adjusted for year, age/sex, language region, insurance status, burden of disease, and density of cardiologists. Shaded relief map reprinted from the Federal Office of Topography swisstopo, Switzerland https://shop.swisstopo.admin.ch/en/products/maps/overview/relief and shape files derived from postcode-level shape file used to create map of Switzerland, e.g., https://www.geocat.admin.ch/) under a CC BY license, with permission from Alexandra Frank, original copyright 2006.