Brain Surgery Survivors Face 18% Higher Death Rate and Lasting Cognitive Deficits a Decade Later

Chronic subdural hematoma (cSDH) — a collection of blood between the brain and its outer membrane — is one of the most common neurosurgical conditions in older adults, and its incidence is rising with an aging population. While surgical drainage is generally effective at relieving acute symptoms, very little was known about what happens to patients over the following decade. This study from Bern University Hospital in Switzerland provides the most comprehensive long-term outcome data yet, tracking survival, cognitive function, and quality of life for up to 10 years after surgery.

The study enrolled 359 adults surgically treated for cSDH between June 2012 and August 2016 at a single tertiary center. The mean patient age was 73.4 years, and 32.6% were female. Mortality follow-up extended through December 31, 2023 (mean follow-up 9.55 years), while health-related quality of life (HRQoL) was assessed cross-sectionally through December 31, 2024 (mean 10.05 years). For mortality analysis, each patient was matched to Swiss general population controls by age, sex, and birth month. Among survivors, 147 completed the HRQoL questionnaire and were compared against age- and sex-weighted European reference norms.

The survival findings were striking. At one year, cSDH patients had a survival rate of 92.8% versus 98.8% in matched controls — a 6.0 percentage point gap with a standardized mortality ratio (SMR) of 3.22 (95% CI, 2.10–4.72), indicating that early post-surgical mortality was more than three times the expected rate. By five years, survival was 76.6% versus 88.2% (excess mortality 11.6 percentage points; SMR 1.19). At 10 years, survival was 55.5% versus 73.5% — an 18 percentage point deficit — with a hazard ratio of 2.02 (95% CI, 1.73–2.37; log-rank P<0.001). The SMR at 10 years was 1.12, suggesting a persistent but attenuating excess mortality risk over time.

Among survivors completing HRQoL assessments, cognitive functioning (CF) emerged as the most consistently impaired domain. Men scored a mean of 77.6 (SD 22.6) on CF versus a control mean of 87.38 (P<0.001), and women scored 70.2 (SD 24.8) versus 86.50 (P<0.001). Men also showed significantly lower physical functioning (75.9 vs 83.22; P<0.001), role functioning (74.9 vs 84.87; P<0.001), and social functioning (84.3 vs 90.00; P=0.02). Women showed lower role functioning (69.0 vs 80.91; P=0.02) in addition to cognitive deficits. Importantly, emotional functioning and global quality of life did not differ significantly from population norms in either sex — suggesting patients adapt psychologically even while experiencing objective functional limitations.

The authors argue these findings have direct clinical implications. The early SMR of 3.22 at one year suggests that the perioperative period and immediate post-discharge phase carry the greatest excess risk, possibly driven by comorbidities, recurrence, or complications. The sustained cognitive and functional deficits at 10 years underscore that cSDH is not simply a mechanical problem solved by drainage — it leaves lasting neurological sequelae. The authors call for structured postoperative rehabilitation programs, long-term cognitive monitoring, and care pathways that extend well beyond the acute neurosurgical episode. Caveats include the single-center design, the relatively high non-response rate among survivors for HRQoL assessment (introducing potential survivor and response bias), and the lack of pre-surgical baseline HRQoL data, making it impossible to determine how much impairment predated the hematoma.