Relationship between hospital volume and early outcomes in acute ischemic stroke patients treated with recombinant tissue plasminogen activator

Authors


  • Conflict of interest: None declared.
  • Funding: This study was funded by a Grant-in-Aid for Research on Policy Planning and Evaluation from the Ministry of Health, Labour and Welfare, Japan (No. H22-Policy-031); a Grant-in-Aid for Scientific Research B (No. 22390131) from the Ministry of Education, Culture, Sports, Science and Technology; and a grant from the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST program) from the Council for Science and Teckhnology Policy, Japan (No. 0301002001001).

Abstract

Background

There is controversy whether the annual number of acute ischemic stroke patients receiving stroke thrombolysis per hospital (hospital volume) is associated with outcomes in these patients.

Aims

The study aims to assess the relationship between hospital volume and early outcomes in acute ischemic stroke patients treated with recombinant tissue plasminogen activator.

Methods

Patients with acute ischemic stroke treated with recombinant tissue plasminogen activator from July 1, 2010 to March 31, 2012 were identified in the Japanese Diagnosis Procedure Combination database. Hospital volume was categorized into three levels (low, medium, and high volume) to obtain approximately equal numbers of patients in each group. Primary outcomes were seven-day mortality and functional independence (modified Rankin Scale score of 0 to 2) at discharge. Univariate analyses and multivariate logistic regression analyses fitted with generalized estimating equations were performed.

Results

We identified 7476 eligible patients, including 2339 (31·3%) treated in low-volume hospitals (1–7 patients annually), 2670 (35·7%) in medium-volume hospitals (8–16 patients annually), and 2467 (33·0%) in high-volume hospitals (17–48 patients annually). Seven-day mortality and functional independence at discharge were comparable among the three hospital volume groups (P = 0·17 for seven-day mortality; P = 0·22 for functional independence at discharge). The comparability between groups persisted after multivariate adjustment.

Conclusion

Hospital volume was not significantly associated with seven-day mortality or functional independence at discharge in acute ischemic stroke patients treated with recombinant tissue plasminogen activator in Japan.

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