Table 2.

Change in health-related quality of life over time and impact on concordance of results between rare and non-rare and symptom-specific tools versus the SF-36 and EQ-5D

	Rare Disease		Non-rare Disease		Symptom-specific
	SF-36 (n = 2)	EQ-D (n = 0)	SF-36 (n = 38)	EQ-5D (n = 27)	SF-36 (n = 42)	EQ-5D (n = 7)
QoL change	2 (100%)	–	34 (89%)	23 (85%)	36 (86%)	7 (100%)
Concordance change	0/2 (0%)	–	0/34 (0%)	2/23 (9%)	7/36 (19%)	0/7 (0%)

n = studies with > 1 time point. Rare disease: affecting < 1 in 2000 population; Non-rare diseases: ≥1 in 2000 population