Primary outcomes of the review
Duration of delirium
Only one study reported the duration of delirium (Milisen 2001). This was significantly shorter in the intervention cohort (median = 1 day, interquartile range [IQR] = 1) compared with the non-intervention cohort (median = 4 days, IQR = 5.5, p=0.03, Mann-Whitney U test).
Number of patients recovered from delirium (complete response)
Two RCTs (Cole 2002; Pitkala 2005) reported complete response. The Pitkala (2006) study defined the response rate as a permanent improvement of at least 4 points on the MDAS (severity of delirium scored 0 to 30, with 30 being the worst) at 8 days; although no data or references were supplied to justify the use of this score as the measure for improvement, and the GDG considered this to be a poor measure of complete response.
Cole (2002) reported the number of patients with an improvement in cognitive status, as defined by the MMSE, during the hospital stay (mean length of stay 19 days). “Improvement” was defined as an increase in MMSE of 2 or more points; with no decrease below baseline plus 2 points thereafter. If the MMSE score at baseline was 27 or more, improvement was no decrease below 27; MMSE ranges from 0=poor to 30=excellent; a score of 23 or less indicates cognitive impairment) or ’not improved‘. The GDG decided that ‘the number improved’ was an unsatisfactory definition of recovery from delirium, so the study was not included in the analysis for this outcome.
In the Pitkala (2006) study, the intervention significantly increased the number of patients who had recovered from delirium at 8 days after admission (RR 2.00, 95% CI 1.30 to 3.08) This corresponds to a number needed to treat of 5 (95% CI 3 to 10); . The GDG debated whether a change of 4 points on the MDAS scale would clearly show improvement and considered that any conclusions drawn from the Pitkala (2006) study should be treated with caution.
Secondary outcomes of the review
Cognitive impairment
Three studies (Cole 1994; Milisen 2001; Pitkala 2006) reported cognitive impairment.
The Cole (1994) study reported scores for the SPSMQ, a 10-item questionnaire that evaluates orientation, memory and concentration (0=no impairment to 10=severe impairment) at 8 weeks. There was no difference between the intervention and usual care groups (), although the result is imprecise (MD −1.10 (95% CI −4.95 to 2.75).
The Pitkala (2006) study measured cognitive impairment with the MMSE at 6 months (Pitkala 2006). The study reported a mean score of 18.4 in the intervention group versus 15.8 in the usual care group, but no standard deviations were given (p=0.047 for repeated measures analysis of variance (ANOVA); baseline scores used as covariates). This was just significant.
The Milisen (2001) study reported the mean MMSE scores for the delirious patients in the intervention group and the non intervention group (mean MMSE scores: intervention group (delirious): 15.5; non intervention group (delirious): 9.5); the study reported that although the intervention group showed a higher overall cognitive function this difference was not statistically significant; p values or standard deviations were not reported.
Length of stay
Length of hospital stay was reported by all three RCTs (Cole 1994; Cole 2002; Pitkala 2006). The result for the Pitkala (2006) study is presented as a subgroup as the intervention differed from the other two studies (Cole 1994; Cole 2002).
The Cole (1994) study did not report standard deviations, so the study’s contribution to the meta-analysis of the two studies was not estimable. There was no significant difference between intervention and usual care groups in Cole (2002), although the result is imprecise [MD 0.60 (95% CI −3.90 to 5.10)] ().
In the Pitkala (2006), length of stay appeared shorter in the usual care group. We note that the distribution of lengths of stay was skewed (median 21 days in the intervention group, range 2 to 110 days; median 16 in the usual care group, range 1 to 90 days; mean 29.3 days, SD 25.6 in intervention group and mean 22.4 days, SD 18.4 in control group; means are less than twice SD so data likely to be skewed). The result is imprecise [MD 6.90 (95% CI 0.28 to 13.52)].
Two non RCTs also reported length of hospital stay (Milisen 2001; Naughton 2005). The Milisen (2001) study reported a median of 13.5 days (IQR 3.75 days) for the intervention cohort and 14 days (IQR 5 days, p=0.6) for the non-intervention cohort. The Naughton (2005) study reported that following intervention, a mean of 3.3 days was saved in length of stay following each episode of delirium.
Discharge to long-term care
All three RCTs reported discharge of patients who had become more dependent since their admission. Two studies reported that patients were discharged at a greater level of dependency: Cole (1994) reported the percentage of patients discharged required more care (numbers were calculated as the proportion of patients remaining alive at the end of the study); Cole (2002) reported that living arrangements were arranged hierarchically from least dependent (e.g. home alone) to most dependent (e.g. nursing home); living arrangements at discharge were compared with those at admission and were rated as more dependent, same, or less dependent.
The Pitkala (2006) study reported the number of patients discharged to permanent institutional care, and these represented new admissions to such care as patients already in permanent institutional care at admission were excluded from the study.
The results are presented as subgroups in . There was no significant difference in effect of the intervention on discharge to higher care [OR 1.04 (95% CI 0.19 to 5.65)], a more dependent living arrangement at discharge [OR 0.77 (95% CI 0.31 to 1.92)] or to new long-term care [OR 0.69 (95% CI 0.38 to 1.26)], although the results for all three studies are imprecise.
Excluding the Cole (1994) study due to its possible bias did not materially alter the results (a forest plot showing sensitivity analysis is not presented).
The Rahkonen (2001) study reported the duration of long-term care in the three years of the study. This was a mean of 441 days (SD 366) in the intervention group compared with 535 days (SD 308) in the control group [MD −94 days (95% CI −225.28 to 37.28)] (). The mean age was comparable (82.1 years in both groups) and the study excluded patients with confirmed or suspected dementia, however, individuals with mild cognitive impairment were included.
Health related quality of life (HRQoL)
One report (Pitkala 2008) of the Pitkala (2006) study reported health related quality of life along the following dimensions: mobility, vision, hearing, breathing, sleeping, eating, speech, elimination, usual activities, mental function, discomfort and symptoms, depression, distress, and vitality. Patients were assessed with the 15D questionnaire at baseline and discharge [range 0 (poor HRQoL) to 1 (excellent HRQoL)].
There was a small significantly higher HRQoL for the intervention group (MD 0.06 (95% CI 0.02 to 0.10); . The study reported that there were significant differences for the intervention and usual care group on the following dimensions on the 15D questionnaire: mental function corresponding to cognition and alertness (p<0.001), usual activities corresponding to functioning in activities of daily living (p<0.001), vitality (p= 0.004), depression (p=0.044), and speech (p=0.024).
Mortality
Three RCTs (Cole 1994; Cole 2002; Pitkala 2006) and one non-RCT (Rahkonen 2001) evaluated the number of patients who died: two RCTs at 8 weeks (Cole 1994; Cole 2002) and the other RCT at 1 year (Pitkala 2006) and the non-RCT at 3 years (Rahkonen 2001).
The Cole (1994) study reported that overall 35% (31/88) patients died in 8 weeks (33% [14/42] and 37% [17/46] deaths occurring in the intervention and control groups, respectively) [OR 0.90 (95% CI 0.51 to 1.60)]; the causes of death were not given.
The Cole (2002) study reported that overall 21% (47/227) of patients died (22% [25/113] and 19% [22/114] deaths occurring in the intervention and control groups, respectively) [RR 1.15 (95% CI 0.69 to 1.91)]; and the Pitkala (2006) study reported that overall 32% (56/174) patients died over 1 year (34% [30/87] and 30% [26/87] deaths occurring in the intervention and control groups, respectively) [RR 1.15 (95% CI 0.75 to 1.78)]; the causes of death were not reported in either study.
There was no significant difference between the interventions and usual care in the mortality rates, but the results were very imprecise ().
The non-RCT study (Rahkonen2001) reported that during the three-year follow up, a total of 42% (43/102) patients died, the causes of death were not reported [RR 0.87 (95% CI 0.55 to 1.37)] ().