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

Table 9 Linear regressions between headache-attributed disability¹ and lost paid worktime attributed to migraine by country

Country	HALT question 1 (absenteeism)			HALT question 2 (presenteeism)			HALT questions 1 + 2 (total lost paid worktime)
Country	R²	Equation	p	R²	Equation	p	R²	Equation	p
China	0.04	Y = 0.24x + 1.5	0.003	0.08	Y = 0.45x + 2.4	< 0.001	0.08	Y = 0.69x + 3.9	< 0.001
Ethiopia	0.00	Y = 0.06x + 1.0	0.15	0.01	Y = 0.08x + 1.2	0.07	0.01	Y = 0.14x + 2.2	0.07
India	0.08	Y = 0.24x + 0.4	< 0.001	0.07	Y = 0.17x + 0.2	< 0.001	0.12	Y = 0.41x + 0.6	< 0.001
Lithuania + Luxembourg	0.00	Y = 0.07x + 0.6	0.30	0.05	Y = 0.30x + 0.8	< 0.001	0.03	Y = 0.32x + 1.4	< 0.001
Nepal	0.00	Y = 0.00x + 1.2	0.94	0.00	Y = 0.02x + 0.8	0.57	0.00	Y = 0.02x + 2.0	0.76
Pakistan	0.00	Y = 0.08x + 3.2	0.34	0.01	Y = 0.16x + 4.6	0.11	0.01	Y = 0.21x + 7.4	0.15
Russia	0.00	Y = -0.01x + 0.2	0.72	0.03	Y = 0.13x + 1.6	0.09	0.02	Y = 0.12x + 1.9	0.15
Spain	0.09	Y = 0.25x + 0.3	< 0.001	0.12	Y = 0.50x + 2.4	< 0.001	0.13	Y = 0.69x + 2.8	< 0.001

HALT: Headache-Attributed Lost Time questionnaire. ¹ Calculated as proportion of time in ictal state*disability weight from GBD2015 [49]; significant p-values are emboldened.

ISSN: 1129-2377