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

Background Although the mean arterial pressure (MAP) target of 65 mmHg 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 are unclear. We sought to investigate the relationship between DBP and 28-day mortality 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 h, and the mean DBP during the first 24 h (mDBP(24h)) was recorded. The primary outcome was 28-day mortality. Multivariable logistic regression determined the relationship between mDBP(24h) and 28-day mortality. 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 10 mmHg 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) < 59 mmHg 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 association between mDBP(24h) and 28-day mortality. The poor outcomes in patients with mDBP(24h) < 59 mmHg provide indirect evidence supporting a further DBP goal of 59 mmHg for patients with septic shock after MAP of 65 mmHg was achieved.