Table 1.

Characteristics of Kaiser Permanente Members Aged 65 Years or More, Northern California, 1996–2005

	Study Population at Start of Each Flu Yeara (n = 3,044,531 Person-Years)		Decedents (n = 115,823)
	No.	%	No.	%
Age group, years
65–<70	975,664	32.1	14,864	12.8
70–<80	1,442,172	47.4	44,257	38.2
80–<90	554,927	18.2	43,337	37.4
≥90	71,768	2.4	13,365	11.5
Male sex	1,359,674	44.7	58,802	50.8
Chronic conditions
Chronic obstructive pulmonary disease	122,158	4.0	14,381	12.4
Diabetes	397,151	13.0	23,061	19.9
Coronary artery disease	296,548	9.7	22,574	19.5
Heart failure	124,066	4.1	19,981	17.3
Health statusb
Poor	37,090	4.5	7,323	21.2
Fair	210,292	25.2	14,161	40.9
Good	374,671	45.0	9,962	28.8
Very good	178,786	21.5	2,773	8.0
Excellent	32,547	3.9	391	1.1
Percentile of insurance risk score (predicted cost)c
0–<50th	653,407	49.9	6,805	12.8
50–<90th	524,881	40.1	23,300	43.9
90–<98th	104,877	8.0	15,416	29.1
≥98th	26,197	2.0	7,522	14.2
Pneumonia vaccination, ever	1,700,161	55.8	61,520	53.1
Influenza vaccination in the current flu year	1,913,728	62.9	51,491	44.5

^aMid-September to mid-September.

^bHealth status was self-reported and was available only for patients who were randomly sampled for a visit-based survey about satisfaction with health care that was routinely conducted by Kaiser Permanente. Percentages are percentages of the people with data available.

^cRisk scores were available only for flu years 2001–2002 to 2004–2005. Percentages are percentages of the people with data available.