Oversight of human subject research has evolved considerably since its inception. However, previous studies identified a lack of consistency of institutional review board (IRB) determination for the type of review required and whether informed consent is necessary, especially for prospective observational studies, which pose minimal risk of harm. We hypothesized that there is significant inter-institution variation in IRB requirements for the type of review and necessity of informed consent, especially for prospective observational trials without blood/tissue utilization. We also sought to describe investigators' and IRB members' attitudes toward the type of review and need for consent. Eastern Association for the Surgery of Trauma (EAST) and IRB members were sent an electronic survey on IRB review and informed consent requirement. We performed descriptive analyses as well as Fisher's exact test to determine differences between EAST and IRB members' responses. The response rate for EAST members from 113 institutions was 13.5%, whereas a convenience sample of IRB members from 14 institutions had a response rate of 64.4%. Requirement for full IRB review for retrospective studies using patient identifiers was reported by zero IRB member compared with 13.1% of EAST members (p=0.05). Regarding prospective observational trials without blood/tissue collection, 48.1% of EAST members reported their institutions required a full IRB review compared with 9.5% of IRB members (p=0.01). For prospective observational trials with blood/tissue collection, 80% of EAST members indicated requirement to submit a full IRB review compared with only 13.6% of IRB members (p<0.001). Most EAST members (78.6%) stated that informed consent is not ethically necessary in prospective observational trials without blood/tissue collection, whereas most IRB members thought that informed consent was ethically necessary (63.6%, p<0.001). There is significant variation in perception and practice regarding the level of review for prospective observational studies and whether informed consent is necessary. We recommend future interdisciplinary efforts between researchers and IRBs should occur to better standardize local IRB efforts.

Level of evidence

IV.

Background

Subphenotypes have been identified in patients with sepsis and ARDS and are associated with different outcomes and responses to therapies.

Research question

Can unique subphenotypes be identified among critically ill patients with COVID-19?

Study design and methods

Using data from a multicenter cohort study that enrolled critically ill patients with COVID-19 from 67 hospitals across the United States, we randomly divided centers into discovery and replication cohorts. We used latent class analysis independently in each cohort to identify subphenotypes based on clinical and laboratory variables. We then analyzed the associations of subphenotypes with 28-day mortality.

Results

Latent class analysis identified four subphenotypes (SP) with consistent characteristics across the discovery (45 centers; n = 2,188) and replication (22 centers; n = 1,112) cohorts. SP1 was characterized by shock, acidemia, and multiorgan dysfunction, including acute kidney injury treated with renal replacement therapy. SP2 was characterized by high C-reactive protein, early need for mechanical ventilation, and the highest rate of ARDS. SP3 showed the highest burden of chronic diseases, whereas SP4 demonstrated limited chronic disease burden and mild physiologic abnormalities. Twenty-eight-day mortality in the discovery cohort ranged from 20.6% (SP4) to 52.9% (SP1). Mortality across subphenotypes remained different after adjustment for demographics, comorbidities, organ dysfunction and illness severity, regional and hospital factors. Compared with SP4, the relative risks were as follows: SP1, 1.67 (95% CI, 1.36-2.03); SP2, 1.39 (95% CI, 1.17-1.65); and SP3, 1.39 (95% CI, 1.15-1.67). Findings were similar in the replication cohort.

Interpretation

We identified four subphenotypes of COVID-19 critical illness with distinct patterns of clinical and laboratory characteristics, comorbidity burden, and mortality.