Table 1.

Distribution of multimorbidity measures in Health and Retirement Study-Medicare participants at baseline, 2006.

	Multimorbidity Weighted Index (MWI)-ICD	Disease Count	Charlson index	Elixhauser score
Mean (SD)	9.1 (7.7)	5.1 (3.3)	1.9 (2.2)	3.2 (2.7)
Median (IQR)	7.1 (3.3–13.0)	5.0 (3.0–7.0)	1.0 (0.0–3.0)	3.0 (1.0–4.0)
Range	0–52.4	0–25	0–19	0–18
Number of unique values	5891	24	19	19
% with value of 0	5.04	5.04	34.31	13.07
Robust scale estimator Sn (SE)	6.5 (6.5)	3.6 (3.6)	1.2 (1.2)	2.4 (2.4)
Gini index (0.5 = balance)	0.43	0.35	0.60	0.45

Abbreviations: IQR, interquartile range; MWI-ICD, International Classification of Diseases, Ninth Revision coded multimorbidity-weighted index; SD, standard deviation; SE, standard error