Table 3.

Utilization and Mortality for 10 Subgroups of Beneficiaries Based on Frequency and Temporal Regularity of Primary Care Visits (Total n = 378,862)

Visit frequency-based group (number)a	Subgroup name (symbol)b	N	% of total sample	Mean number of primary care visits/year	Coefficient of variation (mean)c	Coefficient of variation (range)d	Average comorbidity score (HCC)e	Death before end of studyf
Least frequent visits (1)	Regular (1R)	75,776	20%	3.3	0.5	0–0.8	0.8	5.7%
	Irregular (1I)	75,775	20%	3.2	1.1	0.8–3.0	0.9	6.2%
Less frequent (2)	Regular (2R)	37,902	10%	5.3	0.6	0–0.8	1.1	8.4%
	Irregular (2I)	37,901	10%	5.3	1.1	0.8–3.1	1.1	8.9%
Moderately frequent (3)	Regular (3R)	37,887	10%	7.0	0.6	0–0.8	1.3	11.3%
	Irregular (3I)	37,886	10%	7.1	1.1	0.8–4.0	1.2	11.5%
More frequent (4)	Regular (4R)	28,401	7.5%	10.1	0.7	0.04–0.8	1.6	17.1%
	Irregular (4I)	28,401	7.5%	10.1	1.1	0.8–4.1	1.5	17.1%
Most frequent (5)	Regular (5R)	9467	2.5%	15.5	0.6	0.01–0.8	2.0	28.4%
	Irregular (5I)	9466	2.5%	15.8	1.2	0.8–4.8	2.0	31.0%

^aGroup 1 has the lowest frequency of primary care visits, and group 5 the highest

^bThe designation “regular” for a subgroup refers to the half of a group with the lower coefficient of variation, which equates to a more regular pattern of primary care visits, whereas “irregular” refers to higher coefficient of variation/less regularity

^cCoefficient of variation is defined as the standard deviation of a set of numbers divided by the mean. As such, it is a standardized and unitless number depicting the variation within a set of numbers. Here, it is used to capture the variability of the interval between primary care visits for each beneficiary

^dThe previous column showed the mean coefficient of variation within each group, this column shows the range within the group

^eHCC is a comorbidity score (Pope et al., 2004) designed to predict spending in future years based on comorbidities and demographic information

^fPercentage of group who died of any cause before the end of the study