Incidence, microbiology, and patient characteristics of skin and soft-tissue infections in a U.S. population: a retrospective population-based study

Table 3 Incidence rates of clinically-diagnosed skin and soft tissue infection episodes and adjusted relative rate ratios: model including race*age interaction

Patient characteristic	Race * age interaction	Adjusted relative rate ratio (95% CI) ^a
All
Gender
Female		1.05 (1.04,1.07)
Male		REF
Diabetes
Yes		1.95 (1.93,1.98)
No		REF
Race/ethnicity
Asian		0.43 (0.41,0.44)
African-American		0.64 (0.61,0.67)
Hispanic		0.73 (0.71,0.75)
Native American		0.94 (0.85,1.04)
Multiracial		0.96 (0.92,1.00)
White		REF
Race/ethnicity * Age
Asian	Under 5	1.86 (1.74,2.00)
	5- < 18	1.18 (1.12,1.24)
	18- < 50	1.05 (1.01,1.10)
	50- < 65	0.86 (0.82,0.90)
	65+	REF
African-American	Under 5	1.51 (1.40,1.62)
	5- < 18	0.99 (0.94,1.05)
	18- < 50	1.59 (1.52,1.66)
	50- < 65	1.19 (1.14,1.25)
	65+	REF
Hispanic	Under 5	1.22 (1.14,1.30)
	5- < 18	0.92 (0.88,0.96)
	18- < 50	0.96 (0.93,0.99)
	50- < 65	0.91 (0.87,0.94)
	65+	REF
Native American	Under 5	0.99 (0.82,1.20)
	5- < 18	0.81 (0.70,0.93)
	18- < 50	0.98 (0.87,1.10)
	50- < 65	0.95 (0.84,1.08)
	65+	REF
Multiracial	Under 5	0.94 (0.85,1.03)
	5- < 18	0.74 (0.69,0.78)
	18- < 50	0.85 (0.81,0.89)
	50- < 65	0.87 (0.83,0.91)
	65+	REF
White	Under 5	0.95 (0.89,1.00)
	5- < 18	0.78 (0.75,0.81)
	18- < 50	0.80 (0.78,0.82)
	50- < 65	0.78 (0.76,0.81)
	65+	REF

Kaiser Permanente of Northern California, 2009 to 2011
^a Rate ratios were derived from a single multivariate negative binomial model. The entire KPNC membership for years 2009–2011 were summarized into strata by gender, age, race, and diabetes status. Each record in the analytic dataset was one of these strata. The dependent variable was the number of SSTI episodes for all members in the strata. Independent variables were gender, race, race*age, and diabetes status. The log of member years in each strata was used as an offset term. Ref = reference group; CI = 95% confidence interval.

ISSN: 1471-2334