Association between diastolic blood pressure during the first 24 hours and 28 day mortality in patients with septic shock: a retrospective observational study

Abstract Background: Although the mean arterial pressure (MAP) target of 65mmHg was achieved, diastolic blood pressure (DBP) was still low in some septic shock patients. The effects of DBP on the prognosis and optimal target for patients with septic shock remains unknown. We sought to investigate the relationship between DBP and mortality at 28 days in septic shock patients. Methods: In this retrospective observational study, we obtained data from the Chinese Database in Intensive Care (CDIC). We included patients with an admission diagnosis of septic shock and shock was controlled. DBP was measured every 1 hour, and the mean DBP during the first 24h (mDBP 24h ) was recorded. The primary outcome was mortality at 28 days. Multivariable logistic regression determined the relationship between mDBP 24h and mortality at 28 days. Results: In total, 1251 patients were finally included. The 28 day mortality of included septic shock patients was 28.3%. The mDBP 24h , not mSBP 24h ,was higher among 28 day survivors compared with non-survivors. 28 day mortality was inversely associated with mDBP 24h (unadjusted OR 0.814 per 10mmHg higher mDBP 24h , p=0.003), with a stepwise increase in 28 day mortality at lower mDBP 24h . The 28 day mortality of patients with mDBP 24h <59 mmHg had an absolute risk reduction of 9.4% (p=0.001). And mDBP 24h <59mmHg was the remaining high risk factor inversely associated with 28 day mortality after multivariable adjustment (adjusted OR 1.915, 95% CI 1.037-3.536, p=0.038), while mMAP 24h and mSBP 24h were not. Conclusion: In patients with septic shock after initial resuscitation, we observed an inverse relationship between mDBP 24h and 28 day mortality. The poor outcomes in patients with mDBP 24h <59mmHg provide indirect evidence supporting a further DBP goal of 59 mmHg for patients with septic shock after MAP of 65mmHg was achieved.