Statistical Analyses

Normally distributed data were analyzed with two-tailed t tests or chisquare analysis. Nonparametric analyses were used for data that were not normally distributed. A backward elimination modeling strategy for all multivariable logistic regression analyses was used to examine predictors separately for symptoms of PTSD (JMP; SAS Institute, Inc., Cary, NC). Individual interaction terms between the type of nurse (general medical/surgical and ICU) and a variety of other independent variables were entered into the initial model to assess for effect modification. Removal of any of the individual confounding variables was allowed if it resulted in no alteration in the odds ratio (OR) for the outcome variable yet improved the precision of the OR. We determined 95% confidence intervals (CIs) for each independent variable in all multivariable logistic regression analyses. An α value of 0.05 was used for all statistical tests.

RESULTS

Between February and March of 2005, a total of 351 nursing employees (230 ICU nurses and 121 general medical or surgical nurses) at one of three Emory University-affiliated hospitals completed the questionnaire. The nurses were evenly distributed among the three hospitals (98 [28%] worked at Emory University Hospital, 128 [36%] worked at Crawford Long Hospital, and 125 [36%] worked at Grady Memorial Hospital) and were representative of the age and distribution of the nurses in our system. The demographics of the participants stratified by general medical/surgical or ICU nurse are included in Table 1. On average, general medical/surgical nurses worked shorter shifts and more days per week than ICU nurses. The average patient-to-nurse ratio for general medical/surgical nurses was significantly higher when compared with the ICU nurses (6:1 [range, 5:1-6:1] vs. 2:1 [range, 2:1-2:1]; p

ICU and general medical/surgical nurses report an equivalent amount of stress in their life outside of the hospital (3.8 ± 1.6 vs. 3.9 ± 1.6 on a scale of 1-7; p = 0.7). Twenty-four percent (95% CI, 18-29) of the ICU nurses were positive for symptoms of PTSD, compared with 14% (95% CI, 8-20) of the general medical/ surgical nurses (p = 0.03). While adjusting for differences in primary hospital of employment, gender, marital status, primary shift (day vs. night), or being responsible for the primary household income, being an ICU nurse was the only variable that remained significantly associated with positive symptoms of PTSD (OR, 1.45; 95% CI, 1.24-1.72; p = 0.02). There was no difference in the percentage of ICU or general medical/surgical nurses who had symptoms consistent with possible anxiety (18 vs. 22%; p = 0.36), depression (31 vs. 27%; p = 0.48), or anxiety or depression (35 vs. 35%, p = 0.98) on the HADS questionnaire. The percentage of ICU or general medical/surgical nurses who had symptoms of possible anxiety and depression (14 vs. 15%; p = 0.89) was not different.