Patient selection
Consecutive patients with acute spontaneous ICH (< 24 h) were retrospectively enrolled from the First Affiliated Hospital of Wenzhou Medical University, Zhejiang Province, China, between January 2018 and August 2019. A diagnosis of ICH was confirmed by computerized tomography (CT) scan of the head and was made according to the diagnostic criteria of the guidelines for the management of ICH[19].
Patients were eligible if: (1) they had a diagnosis of ICH that met the criteria of spontaneous ICH; (2) their hematoma was located in the basal ganglia (internal or external capsule, caudate nucleus, putamen, or more than one of the abovementioned structures); (3) the hematoma volume was between 25 mL and 40 mL; (4) 40 ≤ age ≤ 75 years; and (5) the patients reached the hospital within 24 h of ictus. Whereas they were ineligible if: (1) the hemorrhage was induced by an aneurysm, angiographically proven arteriovenous malformation, infarction, trauma, or tumor; (2) the hemorrhage originated from the cerebellum, brainstem or lobes; (3) they had severe pre-existing physical or mental disabilities or comorbidities that could interfere with the assessment of their outcomes; (4) they had coagulation disorders; (5) they had a prior history of stroke with neurological deficits; or (6) patients who needed urgent evacuation because of a hernia.
Baseline parameters and treatment procedure
Demographics, medical history, medication, the time between ictus and arrival at the emergency department, and baseline clinical and radiological information were obtained from the emergency and hospitalization datasets. The baseline volume of ICH was calculated by the formula A x B x C/2 according to the CT scan[20]. Intraventricular hemorrhage (IVH) was not included in the volume calculated. The patient’s conscious disturbance and neurological function were evaluated through the Glasgow coma score (GCS) and modified Rankin score (mRS) at the time of admission.
Patients were divided into a surgery group and a conservative treatment group. For patients in the surgery group, the hematoma was carefully drained under direct vision through a microscope via a small penetration in the superior temporal gyrus or other noneloquent area. Decompressive craniotomy was performed if necessary. In the conservative treatment group, no invasive procedures were applied. All patients were given the best medical treatment guided by the International Recommendations[19] and if necessary, they were individualized for particular patients.
Outcomes
The primary outcome was a prognosis-based favorable or unfavorable outcome dichotomized from the Extended Glasgow Outcome Scale (GOSE) at 12 months after ictus. GOSE was evaluated from the answers to 14 questions in a questionnaire completed by the patients or their relatives[21]. The questionnaires were completed by telephone interviews conducted by independent, blinded to treatment group interviewers.
The prognostic outcome was designed to be different types of outcomes with two different levels for the patient’s status[22]. Prognosis was estimated using the following algorithm, which had been developed from patients with a broad range of different ICH:
Prognostic score = 10xGCS-age-0.64xvolume
Patients were divided into good and poor prognosis groups using the predefined cutoff of 27.672 for supratentorial intracerebral hemorrhage[16]. For patients with a poor prognosis, the outcome was regarded as favorable if GOSE was better than upper severe disability, while for patients in the good prognosis group, favorable outcomes included a good recovery and moderate disability.
Secondary outcomes included the incidence of hospitalized complications, mortality and prognosis-based dichotomized mRS at 12 months follow-up. For the good prognosis group, a Rankin score of 0–2 was judged as a favorable outcome, while for those with a poor prognosis, the equivalent thresholds were three for the Rankin score. Death was stratified as an unfavorable outcome for all patients.
Statistical analysis
Matching analysis was performed on the basis of the estimated propensity scores of observed clinical factors that may influence decision making for treatment strategy, that is, the patient’s age, GCS, volume of hematoma and midline shift. Patients in the two groups were one-to-one matched for the similarity of their propensity score by nearest neighbor matching.
Data for categorical variables were reported as the number and percentage in each group. Percentage was reported to no decimal places. For continuous variables, the mean and SD, as well as the median, quartiles, maximum and minimum were calculated. Quantitative data were analyzed by Student’s t-test or the Mann-Whitney test depending on the distribution. Categorical data were compared by Pearson’s chi-squared test or continuous corrected χ2 tests where appreciate. Outcomes were reported as odds ratios (OR) with 95% CI.
The primary outcome was a simple categorical variable compared by Chi-square tests for prognosis-based favorable and unfavorable outcomes on GOSE. After adjusting for the covariates GCS, volume of the hematoma, and midline shift, multivariate-adjusted binary logistic regression was performed to calculate the OR and 95% CI for the primary outcome. Secondary analysis consisted of χ2 tests for mortality, and 12 months prognosis-based mRS.
Prespecified subgroup analyses were also undertaken for age (< 55, ≥ 55), volume of the hematoma (≤ 30, > 30), midline shift (≤ 6, > 6), GCS (5–8; 9–12; 13–15), IVH, and status of the worse limb (weak, paralyzed), and two prognosis groups (good and poor). P values were reported to three decimal places or at P < 0.0001. In this study, statistical significance was defined as a two-tailed p value less than 0.05 (P < 0.05). The analyses were performed with SPSS 23.0 (IBM Corp.) or the Stata Statistical Software Release 12.0 (College Station, TX, StataCorp LP).