TABLE 3.

Spearman's rho correlation coefficient r_s between the Brief Illness Perception Questionnaire (Brief IPQ) and selected measures (n=52)

Brief IPQ item	Consequences			Outcomes
	Breathlessness severity		Distress	Health-related quality of life	Self-management
	NRS worst breathlessness over 24 h	Dyspnea-12	NRS distress due to breathlessness	Health-related quality of life	NRS self-efficacy for managing breathlessness	CRQ mastery
Consequences	rs=0.57, p<0.001*	rs=0.57, p<0.001*	rs=0.47, p<0.001*	rs= −0.54, p<0.001*	rs= −0.53, p<0.001*	rs= −0.58, p<0.001*
Timeline	rs= −0.08, p=0.602	rs=0.06, p=0.683	rs= −0.16, p=0.249	rs=0.06, p=0.682	rs= −0.15, p=0.295	rs=0.01, p=0.947
Personal control	rs= −0.22, p=0.116	rs= −0.16, p=0.285	rs= −0.26, p=0.158	rs=0.05, p=0.740	rs=0.28, p=0.045	rs=0.22, p=0.120
Treatment control	rs= −0.12, p=0.416	rs=0.00, p=0.994	rs=0.04, p=0.962	rs= −0.10, p=0.486	rs=0.12, p=0.416	rs=0.02, p=0.872
Identity	rs=0.61, p<0.001*	rs=0.76, p<0.001*	rs=0.60, p<0.001*	rs= −0.65, p<0.001*	rs= −0.50, p<0.001*	rs= −0.65, p<0.001*
Concern	rs=0.41, p=0.002*	rs=0.61, p<0.001*	rs=0.41, p=0.003*	rs= −0.54 p<0.001*	rs= −0.59, p<0.001*	rs= −0.62, p<0.001*
Coherence	rs=0.03, p=0.817	rs=0.04, p=0.772	rs= −0.07, p=0.643	rs=0.04, p=0.754	rs= −0.04, p=0.783	rs= −0.06, p=0.535
Emotional response	rs=0.50, p<0.001*	rs=0.79, p<0.001*	rs=0.76, p<0.001*	rs= −0.81, p<0.001*	rs= −0.38, p<0.001*	rs= −0.78, p<0.001*

r_s= ±1: perfect correlation; r_s= ±0.50–0.99: strong correlation; r_s= ±0.30–0.49: medium correlation; r_s< ±0.29: small correlation; r_s=0: no correlation. A Spearman's r_s of ≥0.50 was predefined as the threshold to denote important associations between variables, highlighted in bold. *: correlation significant at p<0.008 level (two-tailed). NRS: numerical rating scale (0–10); CRQ: Chronic Respiratory Disease Questionnaire.