Table 1.
Univariate and Multivariable Analysis of Factors Associated With Methicillin-Resistant Staphylococcus aureus-Positive Clinical Culturesa
| Factorb | Univariate Analysis |
Multivariable Analysis |
||||
|---|---|---|---|---|---|---|
| MRSA Clinical Cases (n = 390) | Controls (n = 1800) | OR (95% CI) | P Value | OR (95% CI) | P Value | |
| Gender | ||||||
| Male | 327 (84%) | 1545 (86%) | 0.86 (.6–1.2) | .31 | — | — |
| Female | 63 (16%) | 255 (14%) | ||||
| Age in years, mean (SD) | 36.1 (11.5) | 33.5 (11.1) | 1.02 (1.01–1.03) | <.001 | 1.02 (1.01–1.03) | <.001 |
| Race/Ethnicity | ||||||
| Non-Hispanic Black | 269 (69%) | 1207 (68%) | 1.4 (1.02–2) | .04 | 1.4 (.9–2) | .12 |
| Non-Hispanic White | 71 (18%) | 256 (14%) | 1.8 (1.2–2.6) | .01 | 2 (1.3–3.1) | .003 |
| Hispanic | 48 (12%) | 305 (17%) | Reference | — | Reference | — |
| HIV Infection | 32 (8%) | 36 (2%) | 4.4 (2.7–7.1) | <.001 | 4.4 (2.7–7.4) | <.001 |
| Repeat incarceration during study period | 28 (7%) | 39 (2%) | 3.5 (2.1–5.8) | <.001 | 3.7 (2.2–6.2) | <.001 |
| Median jail length of stay, in days | 30 (1181) | 16 (1637) | 1.002 (1.001–1.003) | <.001 | 1.4 (1.3–1.5) | <.001 |
Abbreviation: CI, confidence interval; HIV, human immunodeficiency virus; MRSA, methicillin-resistant Staphylococcus aureus; OR, odds ratio; SD, standard deviation.
a Data for univariate analysis are no. (%) of individuals, unless otherwise indicated.
b Ethnicity data were missing for 34 individuals, and therefore the denominator for the race/ethnicity variable for univariate analysis is 2156. Individuals labeled as both non-Hispanic and “other” race comprised 0.5% of the total study population; these individuals were included as non-Hispanic whites. For the jail-length-of-stay variable, 54 individuals had not been discharged from the jail at end of the study period, and therefore the denominator for this variable for univariate analysis is 2136. The jail-length-of-stay variable was highly skewed, and a natural log transformation was applied to improve the symmetry of the distribution and model fit. For univariate analysis, the median jail length of stay in days transformed to natural log was 3.4 (range 7) for cases and 2.8 (range 7) for controls (OR = 1.4; 95% CI, 1.3–1.5; P < .001). Initial variables included in the model were as follows: gender, age, jail length of stay, HIV, repeat incarceration, race/ethnicity. The Hosmer-Lemeshow goodness-of-fit test, P = .24.