Table 2.
Results of the retrospective cohort study for the analysis of risk.
| Risk factor | Cohort description | Univariate analysis | Multivariate analysis | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Subjects | Cases | Time at riskA | RateB (95%-CI) | RR (95%-CI) | p-valueC | RR (95%-CI) | p-valueC | ||
| Age > 60 | No | 16 | 7 | 428.86 | 1.63(0.78-3.42) | 0.47 | 0.121 | - | - |
| Yes | 29 | 6 | 781.71 | 0.77(0.34-1.71) | (0.18-1.22) | ||||
| female sex | No | 32 | 9 | 869.57 | 1.03(0.54-1.99) | 1.13 | 0.835 | - | - |
| Yes | 13 | 4 | 341.00 | 1.17(0.44-3.13) | (0.40-3.22) | ||||
| MWF-am | No | 36 | 12 | 947.00 | 1.27(0.72-2.23) | 0.30 | 0.218 | - | - |
| Yes | 9 | 1 | 263.57 | 0.38(0.05-2.69) | (0.04-2.04) | ||||
| MWF-pm | No | 34 | 4 | 939.14 | 0.43(0.16-1.13) | 7.79 | < 0.001 | 10.00 | 0.019 |
| Yes | 11 | 9 | 271.43 | 3.32(1.73-6.37) | (2.91-20.86) | (1.47-68.02) | |||
| TTS-am | No | 36 | 12 | 956.14 | 1.26(0.71-2.21) | 0.31 | 0.236 | - | - |
| Yes | 9 | 1 | 254.43 | 0.39(0.06-2.79) | (0.05-2.14) | ||||
| TTS-pm | No | 34 | 12 | 936.29 | 1.28(0.73-2.26) | 0.28 | 0.202 | - | - |
| Yes | 11 | 1 | 274.28 | 0.36(0.05-2.59) | (0.04-1.96) | ||||
| Other | No | 40 | 12 | 1063.71 | 1.13(0.64-1.99) | 0.60 | 0.626 | - | - |
| Yes | 5 | 1 | 146.86 | 0.68(0.1-4.83) | (0.08-4.60) | ||||
| Dialysis after gen2 HCV+ | No | 23 | 2 | 467.57 | 0.43(0.11-1.71) | 3.46 | 0.090 | 1.29 | 0.658 |
| Yes | 22 | 11 | 743.00 | 1.48(0.82-2.67) | (0.82-14.53) | (0.13-12.65) | |||
| Dialysis along gen2 HCV+ | No | 18 | 10 | 578.29 | 1.73(0.93-3.21) | 0.27 | 0.033 | 1.70 | 0.804 |
| Yes | 27 | 3 | 632.28 | 0.47(0.15-1.47) | (0.08-0.89) | (0.16-18.10) | |||
| N. of dialysis | - | - | - | - | - | 0.99 D | 0.291 | - | - |
| (0.97-1.01) | |||||||||
| Overa all | - | 45 | 13 | 1210.57 | 1.07 | - | - | - | - |
Forty-five susceptible subjects underwent HD throughout the 33 weeks considered, among them 13 became incident cases with and overall crude rate of 1.07 events per 100 dialysis-week/person. First column risk factor analysed, second column descriptive analysis, third column univariate modified Poisson regression analysis of risk, fourth column multivariate modified Poisson regression. Statistically significant value (p < 0.05) in bold.
A) Time at risk is calculated as week of dialysis person of susceptible subjects; B) the rate is calculated as the number of events per 100 dialysis-week/person; C) p-value is calculated according to Robust standard error; D) estimate increment of risk for each additional HD shift (measure of association are according conventional Poisson regression). RR = rate ratio; CI 95% = 95% confidence interval; gen2 HCV + = genotype 2 hepatitis C virus infected subject; MWF-am = Mondays, Wednesdays and Fridays morning dialysis shift MWF-pm = Mondays, Wednesdays and Fridays afternoon dialysis shift TTS-am = Tuesdays, Thursdays and Saturdays morning dialysis shift TTS-pm = Tuesdays, Thursdays and Saturdays afternoon dialysis shift.