Table 2.
Annual Change in Skin and Soft-tissue Infection (SSTI) Incidence Stratified by Demographic Groups and Change in Number of SSTI Encounters Adjusted by Demographic Characteristics in Univariate and Multivariate Poisson Regression Models
| Characteristic | RR (95% CI) | ||
|---|---|---|---|
| Stratifieda | Univariate Model | Multivariate Model | |
| Year | 0.98 (.98–.99)b | 0.98 (.98–.99)b | 0.98 (.98–.98)b |
| Age group | |||
| Adult (≥18 y) | 0.98 (.98–.98)b | Reference | Reference |
| Pediatric (<18 y) | 1.005 (1.001–1.008)b | 0.67 (.67–.68)b | 0.65 (.64–.65)b |
| Race | |||
| African American | 0.97 (.97–.97)b | Reference | Reference |
| Hispanic | 0.99 (.98–.99)b | 0.79 (.79–.80)b | 0.79 (.79–.80)b |
| Other | 1.00 (1.00–1.00) | 0.74 (.73–.74)b | 0.78 (.77–.79)b |
| White | 0.99 (.99–.99)c | 0.90 (.90–.91)b | 0.97 (.96–.97)b |
| Payer | |||
| Commercial | 0.99 (.99–1.00)b | 0.78 (.78–.78)b | 0.76 (.76–.77)b |
| Low SES | 0.98 (.98–.98)b | Reference | Reference |
| Medicare | 0.99 (.98–.99)b | 0.78 (.78–.79)b | 0.70 (.69–.70)b |
| Other | 1.01 (1.01–1.02)b | 0.73 (.73–.74)b | 0.69 (.69–.70)b |
| US region | |||
| Midwest | 0.98 (.98–.98)b | 1.09 (1.08–1.09)b | 1.04 (1.02–1.03)b |
| Northeast | 0.99 (.99–.99)b | 1.05 (1.04–1.05)b | 1.06 (1.05–1.06)b |
| South | 0.998 (.98–.99)b | 1.12 (1.11–1.13)b | 1.08 (1.07–1.09)b |
| West | 0.98 (.98–.98)b | Reference | Reference |
Abbreviations: CI, confidence interval; RR, rate ratio; SES, socioeconomic status.
aEach RR represents an individual model.
b P < .005.
c P < .05.