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

Table 12 Linear regressions between headache-attributed disability¹ and total lost productivity (HALT questions 1 + 2 + 3 + 4) by headache type and country

Country	Migraine			Probable medication-overuse headache
Country	R²	Equation	p	R²	Equation	p
China	0.14	Y = 1.66x + 7.6	< 0.001	–	–	–
Ethiopia	0.07	Y = 0.79x + 4.1	< 0.001	0.06	Y = 1.04x + 18.5	0.28
India	0.13	Y = 0.69x + 2.7	< 0.001	0.01	Y = 0.30x + 11.6	0.58
Lithuania + Luxembourg	0.10	Y = 0.96x + 3.0	< 0.001	0.00	Y = 0.004x + 22.5	0.99
Nepal	0.02	Y = 0.46x + 4.4	< 0.001	0.02	Y = 0.51x + 13.5	0.27
Pakistan	0.06	Y = 1.11x + 11.5	< 0.001	0.00	Y = -0.10x + 23.3	0.56
Russia	0.07	Y = 0.44x + 4.8	0.007	0.11	Y = 0.64x + 10.9	0.008
Spain	0.18	Y = 1.69x + 5.3	< 0.001	0.04	Y = 0.89x + 30.0	0.14

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