Table 4. Known-groups validity.

Categories	EC-PC total	P valuea
HY-based severity levelsb
Mild	14.15±4.80	<0.001
Moderate	13.73±4.42
Severe	9.42±3.31
CISI-PD severity levelsc
Mild	64.15±18.58	<0.001
Moderate	61.99±18.50
Severe	46.73±10.35
PGIS-based severity levelsd
Mild	63.28±19.33	NS
Moderate	64.94±17.15
Severe	47.03±13.37

Abbreviations: CISI-PD, Clinical Impression of Severity Index for Parkinson’s Disease; EC-PC, Living with Chronic illness-PD Scale; HY, Hoehn and Yahr staging; NS, nonsignificant; PGIS, Patient-Based Global Impression of Severity Scale.

^aKruskal–Wallis test.

^bHY-based severity levels: mild, stages 1 and 2; moderate, stage 3; severe, stages 4 and 5.

^cCISI-PD severity levels: mild 1–7 points; moderate 8–14 points; severe 15 or more points.

^dPGIS-based severity levels: mild 0–2 points; moderate 3 points; severe 4 or more points.