Differences in ICU admissions for the elderly between the United States and the United Kingdom

Background

Conventional wisdom holds that ICUs in the United States are more likely to admit very elderly patients than ICUs in many other developed countries. However, adequately representative datasets upon which this hypothesis could be tested have been lacking. We therefore compared patient age distributions in a very large dataset of US and UK ICU patients.

Methods

We analyzed a dataset of ICU admissions to 352 adult general medical, surgical and medical–surgical ICUs in the United Kingdom and the United States from 1997 to 2004. The dataset was constructed from the UK Case Mix Programme Database (Intensive Care National Audit & Research Centre, UK) and the US Project IMPACT database (Cerner, USA). Both databases include ICUs from a broad mix of hospitals from their respective countries. All variables used in the final dataset were validated as being defined and collected similarly in both countries and patients less than 20 years old were excluded.

Results

The cohort consisted of 635,630 admissions, of which 315,118 (49.6%) were admissions to 172 ICUs in the United Kingdom (excluding Scotland) and 320,512 (50.4%) were admissions to 180 ICUs in the United States. While the UK population is slightly older than the US (median age 39.0 vs 36.3), the median age of admissions to the ICU was 65 years in both countries (interquartile range: UK 51–75 years; US 50–76 years). Medical admissions represented 53.1% of all admissions in the United Kingdom, and 62.9% in the United States. The United States admitted more elderly medical ICU patients (16.8% vs 9.4% of cases 80+ years old) (see Fig. 1). For emergency surgery admissions, a smaller percentage were age 40–60 in the United Kingdom (20.0% vs 27.1% in the US), and a greater percentage were age 60–80 (48.1% vs 41.0% in the US); the age distributions of elective surgery admissions was very similar in the two countries.

Figure 1

Comparison of the age of adult admissions to intensive care in the UK and USA.

Conclusion

The overall age distribution of ICU admissions is similar between the United States and the United Kingdom, but the United States admits many more very elderly patients with acute medical conditions. Although this finding could be due to differences in sampling of ICUs, it most probably represents differences in admissions decisions in the two countries.