Table 2.

Maximal predictive performance (c-statistic) value and length of the lookback period when it is reached (year) (> 65 years old as of April 1st, 2019, Québec [Canada], n > 1.4 million)

			c-statisticb (length of LP when the maximal predictive performance is reached) by health outcomes
List of diseasesa		MM definition	1-year mortality	Hospitalisation (≥ 1/y)	Frequent visits to ED (≥ 3/y)	Frequent visits to GP (≥ 7/y)	Frequent visits to specialist physicians (≥ 10/y)	Polypharmacy (≥ 10/y)
All-inclusive list (L60)		MM2+	0.793 (1)	0.668 (1)	0.696 (1)	0.682 (3)	0.695 (2)	0.710 (3)
		MM3+	0.799 (1)	0.676 (2)	0.708 (3)	0.689 (5)	0.692 (3)	0.723 (5)
		MM4+	0.802 (2)	0.679 (3)	0.714 (4)	0.693 (7)	0.691 (5)	0.733 (7)
Core list (L20)		MM2+	0.800 (2)	0.676 (3)	0.710 (3)	0.696 (6)	0.675 (5)	0.734 (7)
		MM3+	0.801 (4)	0.676 (7)	0.714 (8)	0.699 (14)	0.671 (12)	0.737 (7)
		MM4+	0.798 (7)	0.672 (15)	0.713 (13)	0.695 (20)	0.663 (20)	0.728 (20)
Charlson & Elixhauser list (L31)		MM2+	0.809 (2)	0.677 (3)	0.711 (3)	0.678 (5)	0.682 (4)	0.732 (8)
		MM3+	0.814 (4)	0.680 (5)	0.716 (5)	0.681 (19)	0.677 (9)	0.748 (8)
		MM4+	0.815 (5)	0.681 (11)	0.718 (10)	0.680 (20)	0.672 (19)	0.745 (20)

Abbreviation: ED: emergency department; GP: general practitioners; LP: lookback period; MM2+: multimorbidity defines as ≥ 2 chronic conditions; MM3+: multimorbidity defined as ≥ 3 chronic conditions; MM4+: multimorbidity defined as ≥ 4 chronic conditions; y: year

a: The All-inclusive list groups all ICD codes of chronic diseases into 60 chronic conditions; the Core list includes 20 chronic diseases associated with a high Disable-adjusted life years (DALY) impact; the Charlson & Elixhauser list combines 31 medical conditions included in both indices.

b: The c-statistic value in bold indicate the maximal value observed and the length of the lookback period (year) when the maximal c-statistic value is met for a specific health outcome, for each list of diseases