Fig. 4

Interrupted time-series analysis (ITSA) of the effect of the transition of ICU staffing. Thirty-day survival rates (square dots) with 95% prediction intervals (vertical error bars) are shown. At the transition from the high-former period to the low-mid period, ITSA shows a level change of 4.05% [95% CI, -13.1, 21.2; p = 0.63] and a trend change of -0.94%/month [95% CI, -2.80, 0.92; p = 0.31]. At the transition from the low-mid period to the high-latter period, ITSA shows a level change of 1.35% [95% CI, -13.8, 16.5; p = 0.86] and a trend change of 0.05%/month [95% CI, -0.78, 0.89; p = 0.89] for the 30-day survival rate. ITSA, interrupted time-series analysis; ICU, intensive care unit; CI, confidence interval