Adjusted association between weekly work hours, shifts of extended duration, and adverse health and safety outcomes among PGY2+ resident physicians
| Outcome | Weekly work hours | Shifts of extended duration | Combined categorical weekly work hours and shifts of extended duration | |||||||||
| ≤80 | >80 | P value | None | 1-4 | ≥5 | P value | ≤80 work h/week, no shifts | ≤80 work h/week, ≥1 shifts | >80 work h/week, no shifts | >80 work h/week, ≥1 shifts | P value | |
| Patient safety | ||||||||||||
| Medical errors | Ref | 1.59 (1.41 to 1.79) | P<0.001 | Ref | 1.56 (1.41 to 1.73) | 2.25 (1.99 to 2.53) | P<0.001 | Ref | 1.84 (1.66 to 2.03) | 2.12 (1.70 to 2.64) | 2.30 (1.99 to 2.66) | P<0.001 |
| Preventable adverse events | Ref | 1.52 (1.17 to 1.98) | P=0.001 | Ref | 1.28 (1.01 to 1.63) | 1.70 (1.29 to 2.25) | P<0.05 and P>0.001 | Ref | 1.51 (1.20 to 1.90) | 2.35 (1.50 to 3.69) | 1.82 (1.30 to 2.53) | P<0.001 |
| Fatal preventable adverse events | Ref | 2.32 (1.36 to 3.96) | P<0.05 and P>0.001 | Ref | 1.57 (0.89 to 2.76) | 1.99 (1.04 to 3.81) | — | Ref | 1.85 (1.05 to 3.26) | 3.36 (1.15 to 9.78) | 2.62 (1.23 to 5.56) | P<0.001 |
| Motor vehicle crashes | Ref | 1.29 (1.00 to 1.66) | — | Ref | 1.15 (0.93 to 1.42) | 1.17 (0.92 to 1.49) | — | Ref | 1.09 (0.89 to 1.32) | 0.91 (0.48 to 1.73) | 1.44 (1.08 to 1.93) | — |
| Crashes leaving work | Ref | 1.86 (1.28 to 2.69) | P=0.001 | Ref | 1.51 (1.09 to 2.07) | 1.92 (1.35 to 2.74) | P<0.05 and P>0.001 | Ref | 1.42 (1.05 to 1.93) | 1.07 (0.39 to 2.96) | 2.67 (1.78 to 4.01) | P<0.05 and P>0.001 |
| Near miss crashes | Ref | 1.99 (1.74 to 2.27) | P<0.001 | Ref | 1.37 (1.22 to 1.53) | 2.06 (1.83 to 2.33) | P<0.001 | Ref | 1.47 (1.32 to 1.63) | 1.64 (1.27 to 2.12) | 2.54 (2.19 to 2.94) | P<0.001 |
| Occupational exposures | Ref | 1.42 (1.19 to 1.69) | P<0.001 | Ref | 1.27 (1.11 to 1.45) | 1.54 (1.32 to 1.79) | P<0.001 | Ref | 1.17 (1.02 to 1.33) | 1.23 (0.85 to 1.77) | 1.42 (1.17 to 1.73) | P<0.05 and P>0.001 |
| Percutaneous Injuries | Ref | 1.66 (1.33 to 2.07) | P<0.001 | Ref | 1.24 (1.02 to 1.50) | 1.35 (1.08 to 1.68) | P<0.05 and P>0.001 | Ref | 1.16 (0.96 to 1.40) | 1.34 (0.83 to 2.15) | 1.91 (1.47 to 2.48) | P<0.001 |
| Attentional failures | Ref | 1.85 (1.74 to 1.96) | P<0.001 | Ref | 1.29 (1.23 to 1.35) | 1.95 (1.82 to 2.09) | P<0.001 | Ref | 1.40 (1.34 to 1.48) | 1.75 (1.57 to 1.96) | 2.30 (2.14 to 2.47) | P<0.001 |
All models are adjusted for age, gender, specialty, and cohort. Occupational exposures, percutaneous injuries, and patient safety outcomes are further adjusted for hours in patient care. P values are obtained from likelihood ratio tests. Linearity was assumed for weekly work hours and shifts of extended duration. Significance of increasing work weekly hours and shifts of extended duration was tested across the categorical variables using likelihood ratio tests that tested for a linear trend across categories. Estimates for near miss crashes and attentional failures are incidence rate ratios (95% confidence intervals); all other estimates are odds ratios (95% confidence intervals). Ref=reference group; PGY2+ residents=resident physicians at postgraduate year 2 and above.