The relationship between headache-attributed disability and lost productivity: 2. Empirical evidence from population-based studies in nine disparate countries

Table 8 Spearman correlations between impairment¹ and lost worktime attributed to migraine by country (values of N vary because of zero values in some responses to one or more questions)

Country	HALT question 1 + 2			HALT question 3 + 4			HALT questions 1 + 2 + 3 + 4
Country	N	r_s	p	N	r_s	p	N	r_s	p
China	200	0.22	0.002	203	0.30	< 0.001	203	0.32	< 0.001
Ethiopia	479	−0.05	0.27	479	0.31	< 0.001	479	0.32	< 0.001
India	372	0.28	< 0.001	372	0.05	0.30	372	0.28	< 0.001
Lithuania + Luxembourg	517	0.24	< 0.001	537	0.35	< 0.001	548	0.35	< 0.001
Nepal	674	0.01	0.73	674	0.18	< 0.001	674	0.17	< 0.001
Pakistan	416	0.14	0.005	481	0.24	< 0.001	613	0.32	< 0.001
Russia	108	0.07	0.49	108	0.25	0.008	108	0.25	0.008
Spain	351	0.34	< 0.001	352	0.44	< 0.001	364	0.41	< 0.001

HALT: Headache-Attributed Lost Time questionnaire. ¹ Calculated as proportion of time in ictal state*reported usual headache intensity; significant p-values are emboldened.

ISSN: 1129-2377