{
  "abstract": "Background Stroke remains a leading global cause of death, with treatment timeliness critically determining outcomes. Although the time–efficacy relationship in stroke care is well established, the interplay interaction between treatment delays, care quality and clinical outcomes remains poorly characterised, particularly across different healthcare settings.Methods This nationwide study analysed data from 2 875 119 acute ischaemic stroke (AIS) hospitalisations (2020–2024). After stratifying patients by treatment delay quartiles (Q1–Q4), we performed propensity score matching to balance 24 baseline covariates. To evaluate the detrimental effects of treatment delay on therapeutic benefits, we used logistic regression and doubly robust causal modelling across delay groups. Patients whose overall delay fell within the fourth quartile and received low-quality care were identified as the high-risk group. Multivariable logistic regression was used to identify independent risk factors.Results Low-quality care correlated with longer delays (overall: 1038 vs 981 min, p<0.0001). High-quality care achieved the greatest mortality reduction in Q1 (average treatment effect (ATE) 0.0036, 95% CI 0.0032 to 0.0041) compared with Q4 (ATE 0.0014, 95% CI 0.0012 to 0.0017). Thrombolysis delays had the strongest impact on mortality (Q1 ATE 0.0155, 95% CI 0.0087 to 0.0222; Q4 ATE 0.0068, 95% CI 0.0031 to 0.0106). High-risk subgroups for delayed, low-quality care included: Northwest residents (OR 1.5759, 95% CI 1.5613 to 1.5905), minor stroke (OR 1.8402, 95% CI 1.8302 to 1.8503), self-transport patients (OR 1.1392, 95% CI 1.1340 to 1.1443), and those with comorbidities (renal failure: OR 1.0948, 95% CI 1.0825 to 1.1073; asthma: OR 1.0861, 95% CI 1.0646 to 1.1080) (all p<0.0001).Conclusions The benefits of high-quality care in reducing mortality risk were significantly diminished by delays in hospital admission, examination and thrombolysis. The timeliness and quality of AIS care are influenced by geographic location, admission National Institutes of Health Stroke Scale scores and comorbidity profiles. The highest priority populations for delay reduction and quality improvement were patients who did not use emergency medical services and those with multiple comorbidities.",
  "authors": [
    {
      "affiliations": [
        "Harbin Medical University, School of Public Health, Harbin, China"
      ],
      "name": "Ruize Guo"
    },
    {
      "affiliations": [
        "Harbin Medical University, School of Public Health, Harbin, China"
      ],
      "name": "Mengyang Liu"
    },
    {
      "affiliations": [
        "Harbin Medical University, School of Public Health, Harbin, China"
      ],
      "name": "Qianni Li"
    },
    {
      "affiliations": [
        "Harbin Medical University, School of Public Health, Harbin, China"
      ],
      "name": "Jingkun Li"
    },
    {
      "affiliations": [
        "Harbin Medical University, School of Public Health, Harbin, China"
      ],
      "name": "Meina Liu"
    }
  ],
  "title": "Diminishing returns: how treatment delays undermine the mortality benefits of high-quality stroke care",
  "uid": "a93438c9-7647-5a4b-b9c3-9842a538f3bf"
}