Prevalence of post-intensive care syndrome among Japanese intensive care unit patients: a prospective, multicenter, observational J-PICS study

Background: Many studies have compared quality of life of post-intensive care syndrome (PICS) patients with age-matched population-based controls. Many studies on PICS used the 36-item Short Form (SF-36) health survey questionnaire version 2, but lack the data for SF-36 values before and after intensive care unit (ICU) admission. Thus, clinically important changes in the parameters of SF-36 are unknown. Therefore, we determined the frequency of co-occurrence of PICS impairments at 6 months after ICU admission. We also evaluated the changes in SF-36 subscales and interpreted the patients' subjective significance of impairment.

Methods: A prospective, multicenter, observational cohort study was conducted in 16 ICUs across 14 hospitals in Japan. Adult ICU patients expected to receive mechanical ventilation for > 48 h were enrolled, and their 6-month outcome was assessed using the questionnaires. PICS definition was based on the physical status, indicated by the change in SF-36 physical component score (PCS) ≥ 10 points; mental status, indicated by the change in SF-36 mental component score (MCS) ≥ 10 points; and cognitive function, indicated by the worsening of Short-Memory Questionnaire (SMQ) score and SMQ score at 6 months < 40. Multivariate logistic regression model was used to identify the factors associated with PICS occurrence. The patients' subjective significance of physical and mental symptoms was assessed using the 7-scale Global Assessment Rating to evaluate minimal clinically important difference (MCID).

Results: Among 192 patients, 48 (25%) died at 6 months. Among the survivors at 6 months, 96 patients responded to the questionnaire; ≥ 1 PICS impairment occurred in 61 (63.5%) patients, and ≥ 2 occurred in 17 (17.8%) patients. Physical, mental, and cognitive impairments occurred in 32.3%, 14.6% and 37.5% patients, respectively. Population with only mandatory education was associated with PICS occurrence (odds ratio: 4.0, 95% CI 1.1-18.8, P = 0.029). The MCID of PCS and MCS scores was 6.5 and 8.0, respectively.

Conclusions: Among the survivors who received mechanical ventilation, 64% had PICS at 6 months; co-occurrence of PICS impairments occurred in 20%. PICS was associated with population with only mandatory education. Future studies elucidating the MCID of SF-36 scores among ICU patients and standardizing the PICS definition are required. Trial registration UMIN000034072.