# Should octogenarians and people aged 90 years and over be treated separately in studies of stroke? An evaluation of national audit data

## TL;DR

This study suggests that people aged 90 and over should be analyzed separately from those aged 80–89 in stroke research due to significant differences in outcomes and characteristics.

## Contribution

The study demonstrates that stroke patients aged 90+ have distinct clinical profiles and outcomes compared to those aged 80–89, suggesting the need for separate analysis.

## Key findings

- Patients aged 90+ had higher in-hospital mortality and lower likelihood of functional independence after stroke compared to those aged 80–89.
- Prestroke functional status, hemorrhagic stroke, AF, and thrombolysis were associated with worse outcomes in those aged 90+.
- The proportion of hemorrhagic stroke was lower in those aged 90+ compared to those aged 80–89.

## Abstract

Population studies frequently use ≥80 years for defining ‘very old’ but as mean life expectancy frequently exceeds 80 years internationally, this may no longer be appropriate. Those ≥90 years now represent a significant proportion of stroke patients. We examined national data to examine the differences between those 80–89 years and those 90+ years.

Methods Data from the Irish National Audit of Stroke (2017–22 inclusive), including demographic, admission and outcome data, including prestroke and discharge modified Rankin Scores (mRS), were analysed. Proportional data were analysed using Chi-square statistics.

Data on 26 829 individual stroke events were analysed of which 7329 (27.3%) were in people 80–89 years; 52.8% were women. 1708 events occurred in people ≥90 (6.4%); 70.0% were women. 73.7% of those 80–89 years had mRS < 3 prestroke vs 51.3% of those ≥90 (P < .001). In hospital mortality for people ≥90 was higher (26.8% vs 17.4% P < .001) and they were less likely to have mRS < 3 at discharge (17.0% vs 35.8% P < .001). Proportion of haemorrhagic stroke was significantly lower in those ≥90 (15.3% vs 12.9% P = .015). Only one haemorrhage was reported amongst 31 people ≥100 years. The proportion of atrial fibrillation (AF) detected following stroke was not significantly different (≥90 years: 33.9%, 80–89 years, 32.4% P = .38).

On logistic regression, nonrecovery to independence (mRS >2) in those ≥90 was associated with prestroke mRS, haemorrhagic stroke, AF and being thrombolysed.

There are differences in profiles and outcomes between the groups, and it is now more appropriate to consider them separately.