Validation of a Clinical Complications Scale (CCS) in Patients with Disorders of Consciousness

Validation of a scale for the assessment of clinical complications (Clinical Complications Scale, CCS) on a sample of DoC patients with:

• assessment of inter-rater agreement;
• assessment of concurrent validity with a similar instrument (CoCoS).

This study will be implemented throutgh three phases:

(i) Identification of a group of evaluators at participating centers (n=3 per center; total n=18) and training them to administer the CCS and CoCos scales by group videoconference; (ii) Recruitment of a sample of DoC patients (n=7 per center; total n=42) who will each undergo assessment with CCS (administered twice by two independent assessors, A and B) and with CoCoS (administered by a third independent assessor, C); (iii) Evaluation of the degree of agreement between observers in administering the CCS scale (agreement between evaluators A and B) and evaluation of concurrent validity between CCS and CoCoS scale (agreement between evaluators A/B and C).

The study involves the collection of the following clinical data for each patient on admission and during the following 15 days:

• Demographic data respecting patient anonymity (patient's numeric identification code, age, sex, ethnicity, education);
• Anamnestic data (date and etiology of acute event);
• Clinical data including blood chemistry tests, clinical complications and related therapies administered as per normal clinical reports in use at enrolling units, and referring to the 15-day period following the date of enrollment. Each patient also will be evaluated with CRS-R scale 3-5 times within one week after enrollment for confirmation of the diagnosis of DoC. Assessments with CCS and CoCoS clinical scales completed on clinical reports referring to medical complications that occurred within 15 days of enrollment.

The CCS provides a record of clinical complications in 11 categories corresponding to systems of the body (metabolic abnormalities, disorders-cardiovascular, skin and musculoskeletal problems, gastrointestinal disorders, genito-urinary disorders, respiratory disorders) or categories of clinical problems frequently encountered in the population of patients with DoC (neurosurgical complications, epilepsy and myoclonus, paraosteortropathy, neurovegetative crisis, sepsis; Estraneo et al., 2018). For each category, the severity of complications is graded from 0 (absent complication) to 3 (severe complication) based on the intensity of the therapeutic intervention required, interference with the clinic, and/or frequency and duration of morbid events (an exception is the "sepsis" category for which only presence/absence is recorded). In the case of multiple clinical complications occurring within the same category, the most severe will be considered for the severity score. In this way, a cumulative scale score with range 0-31 can be derived.

Descriptive data from the sample at study entry will be expressed in terms of mean and standard deviation for quantitative variables and as frequencies for nominal variables. For the assessment of inter-rater agreement in the administration of the CCS, Fleiss' weighted K-index will be calculated on the individual subscale scores and the total score of the scale administered to each patient by two different operators. For concurrent validity testing between the CCS and CoCoS scales, Fleiss' weighted K-index will be calculated between the scores at the subscales in common between the two instruments, while Spearman's correlation coefficient for ranks will be calculated on the total scores obtained by patients on the two scales.