Temporal Increase in Strict Spontaneous Intracerebral Hemorrhage Admissions During the First March Following Direct...

Objective: On 28 February 2026, Israel entered direct large-scale hostilities with Iran under Operation Roaring Lion. The opening phase was characterized by repeated missile alerts, civilian protected-space instructions, and rapid reorganization of hospital activity into protected areas. We observed an apparent increase in strict spontaneous intracerebral hemorrhage admissions during March 2026 within our linked neurology/neurosurgery services dataset. The aim of this preliminary single-center study was to determine whether March 2026 was temporally associated with a higher proportional burden of strict spontaneous intracerebral hemorrhage admissions compared with March cohorts from the preceding decade and whether this pattern was also observed for acute ischemic stroke or non-traumatic subarachnoid hemorrhage. Methods: We performed a retrospective observational cohort study of all unique March admissions captured within a linked neurology/neurosurgery services dataset from 2016 through 2026. Hospitalizations were deduplicated by admission number. March 2026 was treated as the first full March occurring after the onset of direct Israel-Iran hostilities on 28 February 2026. Strict spontaneous ICH was defined using diagnosis-text phenotyping that included intraparenchymal or intracerebral hemorrhage terminology while excluding trauma, subarachnoid hemorrhage, subdural hematoma, aneurysm, arteriovenous malformation, tumor-related hemorrhage, cavernoma, venous sinus thrombosis, dissection, and other clearly secondary etiologies. Comparator phenotypes included acute ischemic stroke and non-traumatic subarachnoid hemorrhage (SAH). Results: Across 3855 unique March admissions, 68 met criteria for strict spontaneous ICH. In March 2026, 9 of 223 admissions (4.0%) were classified as strict spontaneous ICH, compared with 59 of 3632 admissions (1.6%) across March 2016-2025, yielding a rate ratio of 2.48 (95% CI 1.25-4.94; p = 0.015). Patients with strict spontaneous ICH in March 2026 were older (mean age 72.3 vs. 65.8 years), and 7 of 9 cases (77.8%) occurred in patients aged ≥70 years compared with 25 of 59 (42.4%) historically (p = 0.073). Acute ischemic stroke did not increase in March 2026 (7.6% vs. 9.4%; p = 0.475), and non-traumatic SAH showed only a non-significant numerical increase (2.7% vs. 1.4%; p = 0.147). Sensitivity analyses showed a directionally consistent but statistically non-significant increase when March 2026 was compared with March 2025 alone (4.0% vs. 1.2%; rate ratio 3.36, 95% CI 0.92-12.27; p = 0.076) and with a rolling 3-year March baseline from 2023 through 2025 (4.0% vs. 2.1%; rate ratio 1.93, 95% CI 0.88-4.23; p = 0.143). In-hospital mortality among strict spontaneous ICH patients was 1 of 9 (11.1%) in March 2026 versus 4 of 59 (6.8%) in March 2016-2025. Conclusions: In this preliminary single-center neurology/neurosurgery services cohort, March 2026 showed a higher proportional burden of strict spontaneous intracerebral hemorrhage admissions than March cohorts from the preceding decade, while acute ischemic stroke did not increase. Sensitivity analyses using March 2025 alone and a rolling 3-year March baseline were directionally consistent but did not reach statistical significance. These findings should therefore be interpreted as a hypothesis-generating temporal association rather than evidence of causality or population-level incidence. Wartime-related psychological stress, sleep disruption, altered healthcare access, blood pressure dysregulation, and medication nonadherence are biologically plausible contributors, but individual-level blood pressure, medication exposure, body mass index, time-to-admission, direct stress exposure, and detailed outcome data were not available in the present dataset. Multicenter, hospital-wide, and registry-based validation with seasonal and systems-level sensitivity analyses is required.