Secondary Outcomes
Three secondary outcomes, in hospital mortality, requirement for renal
replacement therapy and length of stay (LOS) in ICU were also assessed.
Regarding in hospital mortality, a total of 1055 patients in 8 of
studies were observed. Meta-analytic estimates for in hospital mortality
showed that there was no statistically significant difference between
patients treated with NAC and without, as showed in Fig 7 (OR: 0.85,
95% CI: 0.43-1.68)
Regarding the requirement for renal replacement therapy, a total of 686
patients in 4 of the studies were assessed. Meta-analytic estimates did
not show any significant benefit of NAC in reducing the requirement for
renal replacement therapy as showed in Fig 8 (OR: 1.05, 95% CI:
0.38-2.92)
Seven studies (1042 patients) reported length of stay in ICU. All
studies reported the exact length of stay in ICU except one study which
reported the number of patients that had an ICU stay longer than 4 days.
Three studies reported the mean length of stay and standard deviation.
Two studies reported the median length of stay and interquartile range.
One study reported the median length of stay and total range. For meta
analytic estimates to be conducted, a normal distribution had to be
assumed for the three studies that reported the median length of stay.
Thus, the median was approximated to be the mean, and standard deviation
was approximated by dividing the interquartile range by 1.35 and the
total range by 4. Meta analytic estimates of studies that reported the
mean and standard deviation and studies with approximated mean and
standard deviation were conducted separately. Both meta analytic
estimates did not show any benefit of NAC in reducing the length of stay
in ICU as showed in Fig 9A (Mean Difference: 0.27, 95% CI: -2.25-2.79)
and Fig 9B (Mean Difference: 0.00, -0.27-0.27).