Using the Fatigue Severity Scale to inform healthcare decision-making in multiple sclerosis: mapping to three quality-adjusted life-year measures (EQ-5D-3L, SF-6D, MSIS-8D)

Table 1 Summary of respondent characteristics, comparison of estimation and validation datasets

	All baseline data			Estimation dataset			Validation dataset			Difference^a
	Mean	SD	Observations	Mean	SD	Observations	Mean	SD	Observations	t statistic	p value
Measure
FSS	43.73	15.10	1054	43.44	15.16	787	44.60	14.91	267	−1.085	0.278
EQ-5D	0.596	0.295	1346	0.600	0.291	1005	0.584	0.309	341	0.831	0.406
SF-6D	0.646	0.130	632	0.650	0.135	473	0.636	0.113	159	1.141	0.254
MSIS-8D	0.646	0.185	690	0.647	0.190	523	0.641	0.172	167	0.412	0.681
Characteristic
Age	50.67	11.68	1400	50.74	11.73	1048	50.45	11.54	352	0.402	0.688
Duration (years)	9.62	10.01	1347	9.61	10.00	1009	9.68	10.09	338	−0.113	0.910
EDSS score	4.30	2.31	289	4.32	2.34	218	4.22	2.24	71	0.324	0.746
	Percentage		Observations	Percentage		Observations	Percentage		Observations	chi² statistic	p value
Gender
Female	73.86%		1040	74.62%		788	71.59%		252	1.256	0.262
Male	26.14%		368	25.38%		268	28.41%		100
MS type
Relapsing remitting	41.97%		572	42.66%		439	39.82%		133	7.572	0.109
Primary progressive	19.37%		264	18.56%		191	21.86%		73
Secondary progressive	16.95%		231	17.69%		182	14.67%		49
Benign	3.3%		45	3.69%		38	2.10%		7
DK or combination	18.42%		251	17.40%		179	21.56%		72
Missing			45			27			18
Recent relapse^b
Yes	53.55%		732	53.42%		546	53.91%		186	0.025	0.988
No	33.28%		455	33.37%		341	33.04%		114
Don’t know	13.17%		180	13.21%		135	13.04%		45
Missing			41			34			7

SD standard deviation, FSS Fatigue Severity Scale, EQ-5D EuroQoL EQ-5D-3L, SF-6D Short-Form 6D, MSIS-8D Multiple Sclerosis Impact Scale – Eight Dimensions, EDSS Expanded Disability Status Scale, DK don’t know
^aDifference between estimation and validation datasets
^bRelapse in the 12 months prior to completing the baseline questionnaire
nb response numbers are lower for the SF-6D and the MSIS-8D as only version 2 of these questionnaires were included

ISSN: 1477-7525