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Table 2 Incidence rates of clinically-diagnosed skin and soft tissue infection episodes and adjusted relative rate ratios: model with main effects only

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

Patient characteristic Episodes per 10,000 person-years (95% CI) Adjusted relative rate ratio (95% CI) a
All 496 (494-497)  
Gender   
  Female 506 (504-508) 1.05 (1.04,1.07)
  Male 485 (483-487) ref
Age (years)   
  Under 5 579 (573-585) 1.21 (1.17,1.26)
  5- < 18 440 (437-443) 0.88 (0.85,0.90)
  18- < 50 462 (460-464) 0.98 (0.96,1.00)
  50- < 65 488 (485-491) 0.87 (0.85,0.89)
  65+ 652 (648-657) ref
Race/Ethnicity   
  Asian 320 (317-322) 0.51 (0.50,0.52)
  African-American 589 (584-595) 0.94 (0.92,0.96)
  Hispanic 474 (471-477) 0.81 (0.80,0.83)
  Native American 630 (608-653) 1.03 (0.99,1.07)
  Multiracial 600 (591-609) 0.98 (0.96,1.00)
  White 548 (546-550) ref
  Diabetes   
  Yes 928 (921-936) 1.93 (1.90,1.96)
  No 462 (461-464) ref
  1. Kaiser Permanente of Northern California, 2009 to 2011.
  2. 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, age, race and diabetes status. The log of member years in each strata was used as an offset term. The model presented here includes only main effects, and thus represents averages across groups. Ref = reference group; CI = 95% confidence interval.